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Pressure distribution under Wound VAC® therapy vs tie-over bolster dressing

by Justin D. Guiliana DPM1*, Yvonne Cha DPM1, Brent H. Bernstein DPM2

The Foot and Ankle Online Journal 12 (3): 8

Split thickness skin grafts (STSG) are a widely accepted technique for wounds, however the incorporation of the graft to the wound can be easily affected by multiple factors such as the patient’s comorbidities but also the dressing type and its pressure distribution. Securing a newly applied skin graft effectively can often be a difficult task however, a tie-over bolster dressings and the use of negative pressure wound therapy using reticulated open-cell foam (NPWT/ROCF) as delivered by V.A.C.® Therapy (KCI Licensing, Inc., San Antonio, TX) are widely accepted dressings for securing grafts.  The purpose of this study was to compare sub-graft pressure distribution between NPWT/ROCF and tie-over bolster dressing where an experimental graft model was created to compare sub-graft pressure underneath the two dressings. It was found that peak pressure under the NPWT/ROCF graft was 14 pounds per square inch (psi) with a uniform, circular imprint. Peak pressure under the tie-over bolster dressing was 27 psi with three distinct bands of pressure and very low to no pressure distribution between the higher bands of pressure. In this study, NPWT/ROCF appears to have a better uniform pressure distribution compared to the tie-over dressing, which may be related to improved STSG incorporation into the wound.

Keywords: negative pressure wound therapy, pressure distribution, split–thickness skin graft, STSG,  tie-over bolster dressing, VAC® therapy

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0008

1 – Resident, St. Luke’s Podiatry, Bethlehem, PA
2 – St. Luke’s Podiatry, Bethlehem, PA
* – Corresponding author: jguiliana28@gmail.com


Securing newly applied skin grafts to wounds of the lower extremity continues to be a challenge. In order for a split thickness skin graft (STSG) to achieve optimal healing, it requires immobilization of the graft to prevent infection, hematoma, and desiccation. Achieving all three components for successful split-thickness skin graft take has been difficult due to possible complexity in the contour of the soft tissue, and uneven pressure distribution [1].

Traditionally, tie over bolster dressings were applied over STSG to achieve immobilization on the wound in order to achieve optimal healing. However, negative pressure wound therapy using reticulated open-cell foam (NPWT/ROCF) as delivered by V.A.C.® is becoming a more common choice in wounds that have irregularity in the contour of the soft tissue. NPWT/ROCF allows a more uniform pressure distribution on the STSG that are implemented on soft tissue irregularities. This study shows different pressure distributions between tie over bolster dressings, and NPWT/ROCF and to observe the correlation between graft take, and pressure distribution [1].

Methods

Comparative Evaluation of Pressure Distribution under NPWT/ROCF vs. Tie-over Dressings

An experimental graft model was created to compare the sub–graft pressure distribution under a compressed NPWT/ROCF dressing and a tie–over bolster dressing.  A circular, full-thickness wound was made in a porcine extremity (Figure 1A). A tactile sensing system sensor (Tekscan Pressure Measurement System 4.11F, Tekscan, Inc, South Boston, MA) was trimmed to the wound shape and placed in the base of the wound (Figures 1A-C) to measures static pressure distribution. The pressure sensing system uses specialized software and thin, flexible sensors that accommodate most contours and provide accurate local pressure readings.

A human cadaveric mesh STSG was trimmed to the wound size and placed over the sensor (Figure 1D). Figures 2A and 2B show examples of the NPWT/ROCF and tie-over dressings, respectively. The graft/surface interface pressures were measured 1) without a dressing, 2) with a tie-over dressing utilizing 3-0 monofilament nylon suture over a moist cotton ball bolster, and 3) under the NPWT/ROCF dressing at a continuous pressure of -125 mmHg. A non-adherent interface dressing was placed directly over the STSG on all models.

Results

Analysis of Pressure Distribution beneath NPWT/ROCF vs. Tie-Over Dressing Techniques in Porcine Wound Model

The peak pressure under the STSG without a dressing was 6 psi with a uniform, circular implant (Figure 3C). The peak pressure measured under the graft with a tie–over dressing was 27 psi with three distinct bands of pressure and zero to very low pressure distributions between the higher bands of pressure (Figure 3B). The white area indicated no pressure reading. The peak pressure measured underneath the graft with NPWT/ROCF was 14 psi with a uniform circular imprint (Figure 3A). 

Figure 1 (A) Circular, full-thickness wound created in a porcine extremity. (B) Tactile sensing system sensor used to measure subgraft pressure. (C) Tactile sensing system sensor trimmed to wound shape and placed in the base of the wound. (D) Human cadaveric meshed STSG trimmed to the wound size and placed over the sensor.

Figure 2 (A) Tie-over bolster dressing applied over the STSG and pressure sensor. (B) NPWT/ROCF dressing applied over the STSG and pressure sensor.

Figure 3 (A) Pressure under STSG with NPWT/ROCF dressing (14 psi with a uniform circular imprint). (B) Pressure under STSG with tie-over dressing (27 psi with three distinct bands of pressure and no to very low pressure distributions between the higher bands of pressure). (C) Pressure under STSG with no dressing (6 psi with uniform, circular imprint).

Discussion

In many practices, NPWT/ROCF after adequate debridement has become a powerful workhorse in STSG management, particularly in cases of patients with comorbidities or wounds in difficult anatomic locations. The even distribution of pressure aids in immobilization, restriction of shearing to the graft, and prevention of seroma or hematoma formation. Distinct bands of low to no pressure displayed beneath the tie-over dressing in the porcine model indicate a lack of continuous contact between the dressing and graft, thus depriving areas of the graft from the beneficial effects of the dressing.

Our scientific findings dovetail similarly with the histological findings observed in a scientific study by Simman et al. [2]. In a comparative porcine model, NPWT/ROCF showed decreased wound edema, faster narrowing of the separation plane between the graft and recipient wound bed, and earlier termination of the acute inflammatory reaction as compared to a bolster dressing on postoperative days 3, 5, 7, 9, and 11. Authors proposed that a decrease in edema and plane of separation could increase oxygen and nutrient delivery to tissue, leading to accelerated healing [2]. The higher peak pressure observed with the tie-over dressing (27 psi) versus NPWT/ROCF (14 psi) in our study is notable. Further scientific studies would be appropriate to determine optimum pressure at the interface of the wound graft in various patients and wound types. 

The current authors postulate that mechanical factors played a critical role in outcome.  The micromechanical force exerted by the negative pressure and compressed open-cell foam has been shown to cause individual cell deformation and increased proliferation and granulation tissue formation [3]. Following NPWT/ROCF application to cells in an in vitro model, Wilkes et al., [4] reported a change in cell morphology, with cells appearing thicker and with an organized actin cytoskeleton. 

Disclosure: Dr. Brent H Bernstein serves as a consultant to KCI-Acelity Company, however no research financial support or funding was received for the study in this paper.

References

  1. Stone P, Prigozen J, Hofeldt M, Hass S, DeLuca J, Flaherty S. Bolster versus negative pressure wound therapy for securing split-thickness skin grafts in trauma patients. Wounds 16(7):219-223, 2004.
  2. Simman R, Forte R, Silverberg B, Moriera-Gonzalez A, Williams F. A comparative histological study of skin graft take with tie-over bolster dressing versus negative pressure wound therapy in a pig model: a preliminary study. Wounds 16(2):76-80, 2004.
  3. Saxena V, Hwang CW, Huang S, Eichbaum Q, Ingber D, Orgill DP. Vacuum 275 assisted closure: microdeformations of wounds and cell proliferation. Plast Reconstr Surg 114(5):1086-1096, 2004. 
  4. Wilkes RP, McNulty AK, Feeley TD, Schmidt MA, Kieswetter K. Bioreactor for Application of Subatmospheric Pressure to Three-Dimensional Cell Culture. Tissue Eng 13(12):3003-3010, 2007.

Total ankle arthroplasty with custom prosthetic fibular implantation

by Zachary Ritter, DPM, MS, FACFAS1*,  Melody Stouder DPM, AACFAS2, Christine Nolan, DPM, AACFAS1

The Foot and Ankle Online Journal 12 (3): 7

When a malpositioned and painful ankle arthrodesis fails conservative treatment, conversion to a total ankle arthroplasty could be considered as a suitable surgical option. Literature provides several studies demonstrating the high risk of converting an ankle arthrodesis to a total ankle arthroplasty when the patient is lacking a distal fibula. The lack of a structurally supportive osseous and ligamentous complex laterally can lead to increased motion and aseptic loosening, thus contributing to a higher rate of failure. We present a case report in which a painful ankle arthrodesis with prior fibular resection was converted to an ankle arthroplasty utilizing a prosthetic distal fibula along with syndesmotic and lateral ankle ligament reconstruction, including a two year follow-up. To our knowledge, this is the first incidence of prosthetic fibular implantation mentioned in the literature.  

Keywords: ankle arthrodesis conversion, custom fibula, fibular implant, fibular resection, prosthetic fibula

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0007

1 – Susquehanna Health Foot and Ankle Specialty Care, 1201 Grampian Blvd Williamsport, PA 17701
2 – Foot and Ankle Specialists of the Mid-Atlantic, Hagerstown Division, 1110 Medical Campus Road, Hagerstown, MD, 21742
* – Corresponding author: ztritter@msn.com


Although the ankle arthrodesis is a standard of care treatment for end-stage ankle osteoarthritis, it can still result in negative outcomes for the patient. Some of the adverse outcomes include adjacent joint arthritis, pain, and dysfunction [1]. Considerable activity limitation, foot pain, and disability have all been reported following an ankle arthrodesis [1,2]. Treatment of the painful ankle arthrodesis can create a difficult challenge. Until recently, the most common surgical options included ankle fusion revision, tibiotalocalcaneal fusion, and transtibial amputation [3].

If the painful ankle fails conservative treatment, one should consider the need for conversion of an ankle arthrodesis to a total ankle arthroplasty (TAA). Survival rates of ankle prostheses have improved over the years due to less bone resection, larger bone support, uncemented fixation, and proper ligament balance [4].  Despite these advancements, TAA complications still occur; with failure rates ranging from 0-50% [5,6]. Conversion to a total ankle arthroplasty is a more recent solution, potentially restoring pain free ankle range of motion and dissipating the increased load dispersed among adjacent joints [3]. 

Studies have demonstrated that there is a higher risk of complications and implant failure when converting an ankle arthrodesis to a total ankle arthroplasty if the patient has undergone previous fibular resection. The absence of a rigid bony and soft tissue structure along the lateral ankle can lead to increased motion and aseptic loosening. Therefore, when examining a surgical candidate for a total ankle arthroplasty conversion, stability of the ankle should be taken into consideration. In this case study we discuss the importance of adjunctive procedures that should be taken into account when converting a patient who lacks a distal fibula to a TAA. Pre-operatively, a prosthetic fibula was designed. A patient with a painful ankle arthrodesis and a previously resected fibula was converted to a TAA with additional implantation of a prosthetic fibula and reconstruction of the lateral ankle ligament complex.

Case Report

A 56-year-old female with a past medical history of hypothyroidism, vitamin D deficiency, and hypertension presented to our office in January of 2014 with a painful and malpositioned left ankle arthrodesis. She had a left ankle open reduction internal fixation in December of 2003. Secondary to degenerative disease and pain, she underwent an ankle arthrodesis with fibular resection in February of 2008 (Figure 1). She described her current pain as severe in the foot and ankle, which worsened with walking and increased activity. The pain required her to wear shoes with a higher heel or heel lift at all times. Heel elevation managed to palliate her symptoms. She had seen prior specialists and was told that she could not have a total ankle arthroplasty secondary to the absent fibula. At that time she had refused a fusion revision or bracing, so she continued her daily routine wearing an orthosis with shoe gear modification.

After 2 years of conservative treatment with minimal pain improvement, she returned to the office in the Fall of 2016. The option for a total ankle arthroplasty with a prosthetic distal fibula was discussed with her, and she was in agreement. 

Clinical examination included evaluation of the foot and hindfoot while standing, sitting, and walking. Hindfoot alignment was assessed with the patient standing and noted to be neutral. Stability and mobility of the ankle and subtalar joint were assessed manually. Radiological examination included conventional weight bearing radiographs of the ankle. A CT scan of her contralateral ankle was performed in order to replicate the structure of her fibula.  These CT images were mirrored to create a fibular implant designed by Additive Orthopedics (Figure 2). 

Figure 1 Pre-operative  ankle arthrodesis with prior fibular resection. A) Antero-posterior view  B) Lateral view C) Pre-operative planning.

Several prosthetic fibulas with varying lengths, design, and hole positions were designed.   

She was taken to the operating room in February of 2017 for surgical intervention. The patient was placed on the operating room table in the supine position, utilizing general anesthesia and a thigh tourniquet.  

Figure 2 Prosthetic fibula;  A) Antero-posterior view B) Lateral view.

She underwent conversion of a left ankle arthrodesis to a total ankle arthroplasty using a 3rd generation Inbone (Wright Medical) implant according to standard manufacturing protocol.  A curved osteotome was employed to open the existing fusion along the anatomic contour of the previously resected tibio-talar joint.  The ankle was then positioned neutrally based upon intraoperative examination and preoperative calculations. 

The residual distal fibular stump was cut to appropriate length using a sagittal saw. The stem of the prosthetic fibula was then inserted into the medullary canal of the proximal fibula. It was fixated to the proximal fibula using three 3.5mm bicortical screws. A fourth screw was inserted through the prosthetic into the tibia for syndesmotic fixation (Figure 3). Lastly, a gracilis tendon allograft was inserted through a pre-designed hole within the distal prosthetic fibula and fixated to the talus and calcaneus using biotenodesis anchors (Figure 4). The positioning of the hole for the tendon graft in the distal prosthetic was designed and based off of the origin points for the ATFL and CFL. 

Post-operatively, the patient maintained strict non-weight bearing to the surgical limb. After four weeks she was allowed to begin 50% weight bearing. She was then transitioned from her boot as guided by physical therapy. She began passive range of motion at week two and formal physical therapy at week six. 

At approximately three months postoperatively, radiographs revealed disruption of the syndesmotic fixation screw.  

Figure 3 Post-operative radiographs. A) Antero-posterior view   B) Lateral view.

Figure 4 Insertion of the tendon allograft through the distal fibular prosthesis.

At that time the patient revealed that she had returned to unrestrained high demand activity prematurely (including hiking and bowling). 

Five months postoperatively the clinical position was well maintained; she continued normal activity without restriction, and was pleased with her newly reestablished anatomic gait.  At one year follow-up the patient exhibited some intermittent discomfort with prolonged demand and weather pattern changes. She was able to participate in both daily and moderate demand exercise activity without limitation. She had near gained anatomically normal ankle range of motion, while maintaining overall stability and functionality (Figure 5).  She did have fractured syndesmotic fixation, but demonstrated no clinical findings of concern.

Figure 5 One year post-operatively. A) Antero-posterior view B) Lateral view.

At 14 months post-operatively the patient began to not increased gutter pain, both medially and laterally.  She admitted that she had withheld some information at previous visits, hoping that symptoms would improve. 

It was thought that these symptoms were secondary to progressive syndesmotic widening.  A CT scan did confirm widening, but the implants within both the fibula and ankle remained stable. An attempt was made at ASO type bracing and physical therapy.  Her pain persisted. At that time, the determination was made to revise the syndesmosis.

In July of 2018, the patient underwent syndesmotic revision.  A linear incision was made along the existing surgical scar. Dissection was carried down to the underlying implant. The previously inserted syndesmotic screw was removed. The syndesmosis was debrided and the distal fibula was mobilized. The syndesmosis was at this time reduced with a large tenaculum. Positioning was assessed fluoroscopically.  A tightrope was passed through the inferior syndesmotic hole. The tightrope was secured and the reduction clamp was withdrawn.

To further augment the stabilization, 4.5mm corkscrew anchors were placed within the distal tibia at both the proximal and distal fibular syndesmotic holes. These were stabilized to the implant with endo-buttons.  The proximal corkscrew anchor was a 4.5 mm implant while the distal was a 3.5 mm implant. For added security and stabilization, screw was removed from the proximal stem of the implant and replaced with a new transsyndesmotic screw.

Figure 6 Intra-operative revision A) Antero-posterior view B) Lateral View.

Figure 7 Ten months post Revision A) Antero-posterior view B) Lateral view.

Under live fluoroscopy, the ankle was challenged with internal and external rotation views as well as inversion-eversion. The stability of the syndesmosis and the ankle was maintained. There was no apparent shift in the implants (Figure 6).

Postoperatively, the patient was kept non-weight bearing for 2 weeks.  She was then allowed to weight bear as tolerated on the surgical limb in a boot.  At 6 weeks she resumed home physical therapy and was transitioned to normal activity.

At present, she has resumed normal function.  She does have some intermittent mid-foot and subtalar joint symptoms, for which an orthotic was prescribed.  However, given the rarity of her symptoms, she elected to forgo orthosis support. She has had some persistent valgus rotation to the implant; however, this has remained stable (Figure 7).   

Discussion     

The presence of ankle instability and pathologic motion will often contribute to implant failure.  Aseptic loosening is known to be the most common cause of failure of a total ankle arthroplasty [5]. According to Sadoghi et al, 38% of failures were caused by aseptic loosening [7]. Aseptic loosening refers to the failure of fixation at the bone implant interface, caused by micro or macromotion [8].  Some authors refer to aseptic loosening and subsidence as separate outcomes. However, subsidence has been referred to as macroscopic motion of the implant, while aseptic loosening implies non macroscopic loosening [8]. A systematic review by Glazebrook demonstrated that when a TAA went on to failure it was caused by aseptic loosening 70% of the time [5]. Aseptic loosening was therefore considered a high-grade complication.  Another study by Brunner et al., showed that aseptic loosening and subsidence required a revision in 32% of the patients who received a 3 component mobile bearing TAA [9].       

Due to the high incidence of implant loosening, one could perceive how lacking a distal fibula could negatively impact the outcome of the ankle arthroplasty conversion. A study by Greisberg et al looked at 19 ankles which were converted from an ankle fusion to a total ankle replacement. Five of the ankles had extensive thinning or resection of the distal fibula at the original time of fusion. All five of these patients had a complicated course after being converted to arthroplasty. Complications included severe valgus tilting of the talus in the mortise with subsidence, and continued postoperative pain.  Greisberg et al. describes the biomechanics of failure by stating that the mortise is narrowed with resection of the lateral malleolus. Considering this, the implant is positioned relatively medially to maintain proper apposition of the tibial component. This shifts the weight bearing axis lateral to the center of the implant, thus creating a valgus force that eventually overcomes the deltoids, causing talar tilting and bony impingement along the lateral ankle. For this reason, they considered fibular resection to be a relative contraindication [10].      

Pelligrini et al converted 23 ankle fusions to ankle arthroplasties. Two of those patients had a distal fibulectomy during their original arthrodesis, and both of these conversions failed. Therefore these authors state that “their experience with conversion of a total ankle arthroplasty in patients whom the ankle arthrodesis had been performed with complete distal fibular resection reflects prior studies”, referring to studies by Greisberg et al and Hintermann et al [10-12]. They concluded that lack of a distal fibula is a contraindication to arthroplasty conversion. Both of their patients went on to demonstrate progressive valgus talar tilt and lateral talar translation [12].    

The etiology of aseptic loosening can be linked to macromotion as discussed previously in this paper. Soft tissue instability of the ankle is a characteristic which can contribute to increased macromotion. Significant ligament instability has been one of many contraindications discussed when considering an ankle arthroplasty [13]. It was important that we provide the patient with a reconstructed lateral ankle ligament complex in order to reduce macromotion and increase the odds of implant survival. By passing tendon allograft through the prosthesis and anchoring it into the talus and calcaneus we were able to recreate this lateral soft tissue support.       

Another factor, which can contribute to aseptic loosening or subsidence, includes implant design [8]. There must be strong bony ingrowth at the bone-implant interface in order to bypass or avoid loosening. Therefore the addition of implant stems can provide a larger fixation surface, increasing implant stability, reducing micromotion and mechanical stresses [14]. The INBONE total ankle system is a third-generation, fixed bearing implant, which utilizes stem fixation for the tibial and talar components to better distribute stresses [3,5]. The talar component, which has a central sulcus, provides additional coronal stability [14]. Two major indications for INBONE include patients with moderate to severe ligamentous instability of the ankle and incongruent ankle coronal plane deformities.  Stresses transferred from the prosthesis to the bone implant are mitigated by the increased surface area achieved with the stemmed component of the tibia and talus [15,16]. The INBONE system is known for being used in revisions of previously failed ankle replacements, given its inherent tibial stability. For the aforementioned reasons, the 3rd generation INBONE total ankle system was utilized for our case. Inherent tibial component stability is crucial when considering a surgical candidate who has a surgically absent fibula and soft tissue insufficiency.      

Overall, several tactics were employed in order to construct a pre-operative plan before proceeding with this TAA conversion. The first crucial factor considered was the inherent design and stability of the implant, hence the use of the 3rd generation INBONE. The second factor taken into consideration was the lateral bony and soft tissue support structures. The fibula was recreated using a 3D scanned prosthesis, while the soft tissue ATFL and CFL ligamentous support was reconstructed out of tendon allograft. By doing so, the stability of the ankle complex was improved, thus resulting in less micro/macro motion and enhancing the odds of implant survival. With the advancements in prosthetic design, along with a better understanding of ligamentous balancing and component alignment, we believe that the surgical outcomes of converting an ankle arthrodesis with distal fibular resection to a total ankle arthroplasty have the potential to improve.      

To the best of our knowledge, we present the first report of a postoperative prosthetic fibula in order to provide stability for a total ankle arthroplasty.  In conclusion, conversion of an ankle arthrodesis to a total ankle arthroplasty with a prosthetic fibula is a worthwhile limb and function preserving technique. Although complex in nature, this case study shows that the outcome can be advantageous.

In reflection of this first case, small adjustments could be made to the design of the implant—though, the long term success remains to be understood.  Elongation of the fibular component could be considered. This would include an extended intramedullary stem, and proximally translated syndesmotic holes.  The use of tight rope like syndesmotic fixation could also be considered. Otherwise, we believe that the anatomy of the implant was sound.   

References

  1. Coester LM, Saltzman CL, Leupold J, Pontarelli W. Long-term results following ankle arthrodesis for post-traumatic arthritis. J Bone Joint Surg Am. 2001; 83: 219-28. 
  2. Fuchs S, Sandmann C, Skwara A, Chylarecki C. Quality of life 20 years after arthrodesis of the ankle. A study of adjacent joint. J Bone Joint Surg Br. 2003 Sep; 85(7): 994-8.
  3. Huntington W, Hodges Davis W, Anderson R. Total Ankle Arthroplasty for the Treatment of Symptomatic Nonunion Following Tibiotalar Fusion. Foot and Ankle Spec. 2016; 9: 330-335. 
  4. Hintermann B, Valderrabano V, Dereymaeker G, Dick W. The HINTEGRA ankle: rationale and short-term results of 122 consecutive ankles. Clin Orthop Relat Res 2004; 424: 57-68. 
  5. Glazebrook M, Arsenault K, Dunbar M. Evidence-Based Classification of Complications in Total Ankle Arthoplasty. Foot and Ankle Int. 2009; 30: 945-949. 
  6. Spirt AA, Assal M, Hansen ST Jr. Complications and failure after total ankle arthroplasty. J Bone Joint Surg Am. 2004; 86-A: 1172-1178. 
  7. Sadoghi P, Lievensteiner M, Leithner A, Bohler N, Labek G. Revision Surgery after total joint arthroplasty: a complication-based analysis using worldwide arthroplasty registers. J Arthoplasty 2013; 28: 1329-32.
  8. Penner M, Almousa S, Kolla L. “Aseptic Loosening.” Total Ankle Replacement-an operative manual. Baltimore: Deorio and Parekh, 2014. 116-122. Print. 
  9. Brunner S, Barg A, Knupp M, Zwicky L, Kapron AL, Valderrabano V, Hintermann B. The Scandinavian total ankle replacement: long term, eleven to fifteen-year, survivorship analysis of the prosthesis in seventy-two consecutive patients. J Bone joint Surg. 2013; 95(8): 711-718. 
  10. Greisberg J, Assal M, Flueckiger G, Hansen ST Jr. Takedown of Ankle Fusion and Conversion to Total Ankle Replacement. Clin Orthop Relat Res. 2004; 424: 80-88.
  11. Hintermann B, Barg A, Knupp M, Valderrabano V. Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty. J Bone Joint Surg Am. 2009; 91: 850-8
  12. Pellegrini M, Schiff A, Adams S, Queen R, DeOrio J, Nunley J, Easley M. Conversion of Tibiotalar Arthrodesis to Total Ankle Arthroplasty. J Bone Joint Surg Am. 2015; 97:2004-13.
  13. Barg A, Wimmer M, Wiewiorski M, Wirtz D, Pagenstert G, Valderrabano V. Total Ankle Replacement: Indications, Implant Designs, and Results. Dtsch Arztebl Int . 2015; 112: 177-84. 
  14. Lewis JL, Akew MJ, Jaycox DP. A comparative evaluation of tibial component designs of total knee prostheses. J Bone Joint Surg AM> 1982; 64(1); 129-135. 
  15. Cracchiolo 3rd A, Deorio JK. Design features of current total ankle replacements: implants and instrumentation. J Am Acad Orthop Surg. 2008; 16: 530-40. 
  16. Reiley MA. INBONE total ankle replacement. Foot Ankle Spec. 2008; 1: 305-8. 
  17. Gougoulias N, Khanna A, Maffulli N. How successful are current ankle replacements? A systematic review of the literature. Clin Orthop Relat Res 2010; 468: 199-208.  
  18. Demetracopoulos C, Halloran J, Maloof P, Adams S, Parkeh S. Total Ankle Arthroplasty in End-Stage Ankle Arthritis. Curr Rev Musculoskelet Med. 2013; 6: 279-284. 
  19. Hobson S, Karantana A., Dhar S. Total Ankle Replacement in Patients with Significant Preoperative Deformity of the Hindfoot. J of Bone and Joint Surg Br. 2009; 91-B: 481-486.    
  20. Hintermann B, Barg A, Knupp M, Valderrabano V. Conversion of Painful Ankle Arthrodesis to Total Ankle Arthroplasty: Surgical Technique. J Bone Joint Surg Am. 2010; 92 Suppl 1(part 1): 55-66.
  21. Krause F, Windolf M, Bora B, Penner MJ, Wing KJ, Younger AS. Impact of Complications in Total Ankle Replacement and Ankle Arthrodesis Analyzed with a Validated Outcome Measurement. J Bone Joint Surg Am. 2011; 93: 830-9. 
  22. Rosello Anon A, Martinez Garrido I, Cervera Deval J, Mediavilla Herrero D, Gonzalez Sanches M, Carsi Vicent, V. Total Ankle Replacement in Patients with End-Stage Ankle Osteoarthritis: Clinical Results and Kinetic Gait Analysis. Foot and Ankle Surgery. 2014; 20: 195-200. 
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Case study: Schwannoma of the tibial nerve in a patient with a history of neurofibromas

by Zachary T. Ritter, DPM, MS, FACFAS1*, Amy Kruger, DPM2

The Foot and Ankle Online Journal 12 (3): 6

A schwannoma is a common benign tumor of the peripheral nerve sheath.  Schwannomas are rarely found in the foot and typically do not elicit any painful symptoms. We report the case of a large schwannoma eliciting tarsal tunnel like symptoms in a patient with a previous history of neurofibromatosis within the spine. The patient had previously undergone lumbar laminectomy for neurofibromas of the lumbar spine that went on to develop pain in the right foot.  She then underwent extensive workup of this persistent right foot pain. She was treated for plantar fasciitis for several years, until presenting to our clinic. At that time, EMG findings showed tibial neuropathy and medial plantar nerve degeneration; accompanied by MRI findings consistent with a schwannoma of the tibial nerve. The patient underwent surgical excision of the mass. The pathology report revealed an encapsulated biphasic tumor composed of compact hypercellular areas and mixed hypocellular areas with foci of hyalinization with no malignant features measuring 3.7 x 2.5 x 2.0 cm, consistent with a diagnosis of schwannoma.  The patient had an uneventful postoperative course. At one year follow up, she was pain free but had persistent neuropathic changes to the distal forefoot. Currently, there are few reports in the literature of schwannomas arising the tibial nerve eliciting the symptoms of tarsal tunnel syndrome. The incidence of such a schwannoma in association of a patient with a history of neurofibromas is even more rare.

Keywords: neuroma, schwannoma, neurofibromatosis, plantar fasciitis

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0006

1 – Chief of Podiatric Surgery. UPMC Susquehanna. Williamsport, PA.
2 – PGY-3. St. Luke’s University Hospital. Bethlehem, PA.
* – Corresponding author: ztritter@msn.com


A schwannoma is a benign soft tissue tumor of the peripheral nerve sheath. These slow-growing tumors can be difficult to distinguish from other benign tumors based on clinical findings [1]. The principal diagnosis is made histologically by by identifying the principle cellular elements—Schwann cells. This tumor was first described in the thorax [2], and is typically found in the head, neck, and flexor surfaces of the extremities [3]. The most common nerve affected is the eighth cranial nerve; however, the spinal roots as well as the sympathetic, vagus , ulnar, and peroneal nerves are commonly affected as well [3,4]. This tumor is rarely found in the tibial nerve in the region of the tarsal tunnel [5-9]. Finally it is highly uncommon to find this tumor in association with a neurofibroma, with only one report of a schwannoma of the posterior nerve accompanied by a neurofibroma in the tarsal tunnel itself [10]. There are currently no other reports of a patient with a schwannoma eliciting secondary tarsal tunnel syndrome in a patient with a history of symptomatic neurofibromas elsewhere in the literature.

We report a case of a large schwannoma of the tibial nerve located in the tarsal tunnel in a patient with a previous history of neurofibromas in the spine.

Case Report

A 69-year-old female presented to UPMC Susquehanna Foot and Ankle Clinic in July 2015 with right-sided plantar fascial pain accompanied by plantar foot numbness and tingling.  On clinical exam, her foot was neutrally positioned and demonstrated no clinically palpable abnormality. She did have a positive Tinel and Valleix sign. There was mild tenderness along the plantar fascial ligament origin. The patient had been treated by an outside physician for over 5 years with plantar fasciitis.  She had tried various conservative treatment methods including custom orthotics, physical therapy, and a series of corticosteroid injections, all of which provided only temporary relief. She additionally had a history of a prior lumbar laminectomy secondary to pain, after which she began to notice increasing right foot pain and paresthesias.  Her previous spine MRI (June 2014) revealed extramedullary enhancing masses and nerve sheath tumors leading to a diagnosis of neurofibromas.

During her first visit to our clinic in July 2015, an EMG from the previous month was reviewed.  On EMG, there was evidence of tibial neuropathy and degenerative changes of the medial plantar nerve leading to a diagnosis of tarsal tunnel syndrome.  After her first visit, the patient was recommended an additional course of physical therapy, given a script for new custom orthotics, and prescribed a nonsteroidal anti-inflammatory drug, meloxicam (Mobic). Following this course of treatment, the patient’s symptoms did not improve (Figure 1). An MRI was then ordered of the area which revealed a well-encapsulated oval lesion measuring 4.2 x 2.2 x 2.1 cm, appearing hypointense on T1 and hyperintense on T2 consistent with a diagnosis of schwannoma (Figure 2). 

At this point, surgical excision of the mass was recommended to the patient. An oncology referral was discussed, but deferred until after the procedure in the event that surgical pathology findings did not indicate malignancy. She underwent surgical excision of the mass and decompression of the tarsal tunnel in October 2015. 

Figure 1 Preoperative lateral weight bearing radiograph.

Figure 2 Preoperative MRI T1 and T2 images.

The patient was brought into the operating room and placed on the table in a supine position and general anesthesia was administered. Local anesthesia was then administered to the area utilizing a 1:1 mixture of 1% lidocaine plain and 0.5% bupivacaine plain.  A pneumatic calf tourniquet was applied and inflated.  

Attention was then directed to the medial hindfoot, where a curvilinear incision was made just posterior to the medial malleolus and extended to the medial aspect of the glabrous junction at the level of the porta pedis. The incision was then deepened over the tarsal canal. The flexor retinaculum was then identified and released. Extensive tortuous veins were noted within the tarsal tunnel and were gently mobilized. 

Figure 3 Intraoperative image of the soft tissue mass.

 

Figure 4 Intraoperative specimen of the soft tissue mass after removal from tarsal tunnel.

The tibial nerve was then identified and the proximal portion was mobilized. The dissection was then carried distally exposing a large, swollen tibial nerve just proximal to its bifurcation into the medial and lateral plantar nerves.  

A longitudinal incision was then made in the epineurium and the marginal nerve fibers were mobilized  and retracted in an extra capsular fashion. The tumor was then fully exposed. The plane of the tumor capsule was gently dissected from the epineural layers and the tumor was then separated without significant damage to the surrounding nerve fascicles, though there were several small fascicles noted to be entering the tumor at the distal and proximal poles (Figure 3). These fascicles were isolates in an effort to minimize nerve damage, but due to local ingrowth they were impossible to separate from the tumor and were transected.  

Once the tumor was completely removed, the area was thoroughly flushed with sterile saline solution.  The remaining tibial nerve at the level of the lesion was examined and found to demonstrate significant degenerative changes. As there was no obvious tissue to repair, an amniotic graft was then wrapped around the degenerative portion of the nerve in order to promote healing and prevent adhesions.

The incision was then closed in a layered fashion utilizing monocryl suture for the subcutaneous tissues and nylon suture for skin closure. The operative site was then infiltrated with an additional 10 cc of 1:1 mixture of 1% lidocaine plain 0.5% bupivacaine plain.   The incision was then dressed with xeroform and covered with a dry sterile dressing. A modified Jones compression dressing was then applied. The tourniquet was then deflated and a prompt hyperemic response was noted to all digits. 

The pathology report revealed an encapsulated biphasic tumor composed of compact hypercellular areas and mixed hypocellular areas with foci of hyalinization with no malignant features measuring 3.7 x 2.5 x 2.0 cm, consistent with a diagnosis of schwannoma (Figure 4).

The patient was permitted to immediately weight bear postoperatively in a surgical boot. At two weeks postoperative, she underwent suture removal and was transitioned to a street shoe as tolerated. She was followed until one year postoperatively, and found to have no functional limitations, but did continue to notice sensory changes in the plantar foot. 

Discussion

Schwannomas are benign, encapsulated peripheral nerve sheath tumors. They are commonly described throughout the literature by a variety of names: neurilemoma, neuroschwannoma, peripheral glioma, perifibroma, and schwannoma [11,12]. Typically these tumors are found elsewhere in the body (trunk, head, neck, upper extremities) and even more rarely in the lower extremities [2-3, 13].  The foot is noted only to be affected in approximately 10% of cases [3]. There are even fewer noted in the literature to be associated with the tibial nerve and eliciting tarsal tunnel syndromes [5-9].  

Neurofibromas are not typically found in with the foot and ankle.  In a study by Bakotic and Borkowski of primary soft tissue neoplasms of the foot, schwannomas and neurofibromas were noted to account for only 5.4% and 2.7% of all benign soft tissue tumors, and 2.0% and 1.0% of all total neoplasms respectively in the foot and ankle [14].  It is rarely reported to find these two types of tumors in association with one another, with only one report of a schwannoma associated with a neurofibroma in the tarsal tunnel [10]. 

There are currently no other reports of a patient with a schwannoma eliciting secondary tarsal tunnel syndrome and a history of spinal neurofibromas. Currently the recommended treatment for schwannomas of the foot and ankle is open surgical resection [15]. Fortunately, surgical resection has positive results with minimal morbidity and recurrence if resected entirely [16,17]. It is recommended to remove the lesion in total with great care not to damage the nerve through excessive violation of the nerve sheath or compromising the marginal neural fibers. 

We report a case of successful excision of a schwannoma of the tibial nerve located within the tarsal tunnel, eliciting symptoms leading to a diagnosis of tarsal tunnel secondary to tumor. The patient did have a significant medical history of painful neurofibromas of the lumbar spine confirmed on MRI with a subsequent lumbar laminectomy. While the patient did have EMG findings positive for tibial neuropathy and degeneration of the medial plantar nerve, we cannot effectively determine whether the patient’s symptoms were solely related to compression from the longstanding mass within the tarsal tunnel or if they were possibly exacerbated by the patient’s history of lumbar neurofibromas with subsequent surgical intervention. 

The patient’s postoperative course was uneventful.  She did regain some hindfoot and midfoot sensation, while completely eliminating her preoperative pain.  However, parasthesias persisted within the forefoot. 

References

  1. Graviet S, Sinclair G, Kajani N. Ancient schwannoma of the foot. J Foot Ankle Surg. 1995;34(1):46-50.
  2. Ackerman LV, Taylor FH. Neurogenous tumors within the thorax; a clinicopathological evaluation of forty-eight cases. Cancer. 1951;4(4):669-91.
  3. Odom RD, Overbeek TD, Murdoch DP, Hosch JC. Neurilemoma of the medial plantar nerve: a case report and literature review. J Foot Ankle Surg. 2001;40(2):105-9.
  4. Weiss S, Goldblum J, Folpe AL. Schwannoma. In: Enzinger and Weiss’s Soft Tissue Tumors, ed 5, Elsevier Mosby, Maryland Heights MO, 2008, pp. 853-862
  5. Hallahan K, Vinokur J, Demski S, Faulkner-jones B, Giurini J. Tarsal tunnel syndrome secondary to schwannoma of the posterior tibial nerve. J Foot Ankle Surg. 2014;53(1):79-82.
  6. Grossman MR, Mandracchia VJ, Urbas WM, Mandracchia DM. Neurilemmoma of the posterior tibial nerve with an uncommon case presentation. J Foot Surg. 1992;31(3):219-24.
  7. Mangrulkar VH, Brunetti VA, Gould ES, Howell N. Unusually large pedal schwannoma. J Foot Ankle Surg. 2007;46(5):398-402.
  8. Judd T, Jones T, Thornberry L. Schwannoma of the posterior tibial nerve: case study. J Am Podiatr Med Assoc. 2014;104(5):539-43.
  9. Nawabi DH, Sinisi M. Schwannoma of the posterior tibial nerve: the problem of delay in diagnosis. J Bone Joint Surg Br. 2007;89(6):814-6.
  10. Tladi MJ, Saragas NP, Ferrao PN, Strydom A. Schwannoma and neurofibroma of the posterior tibial nerve presenting as tarsal tunnel syndrome: review of the literature with two case reports. Foot (Edinb). 2017;32:22-26.
  11. White NB. Neurilemomas of the extremities. J Bone Joint Surg Am 49:1605-1610, 1967.
  12. Spiegel PV, Cullivan T, Reiman HM. Neurilemoma of the lower extremity. Foot Ankle 6:194-8, 1986.
  13. Jacobson JM, Felder JM, Pedroso F, Steinberg JS. Plexiform schwannoma of the foot: a review of the literature and case report. J Foot Ankle Surg. 2011;50(1):68-73.
  14. Bakotic BW, Borkowski P. Primary soft-tissue neoplasms of the foot: the clinicopathologic features of 401 cases. J Foot Ankle Surg. 2001;40(1):28-35.
  15. Kellner CP, Sussman E, Bar-david T, Winfree CJ. Schwannomas of the foot and ankle: a technical report. J Foot Ankle Surg. 2014;53(4):505-10.
  16. Carvajal JA, Cuartas E, Qadir R, Levi AD, Temple HT. Peripheral nerve sheath tumors of the foot and ankle. Foot Ankle Int. 2011;32(2):163-7.
  17. Kim DH, Ryu S, Tiel RL, Kline DG. Surgical management and results of 135 tibial nerve lesions at the Louisiana State University Health Sciences Center. Neurosurgery. 2003;53(5):1114-24.

A new approach to quantifying the sustainability effects of healthcare: Applied to the diabetic foot

by Stefan Hellstrand1 and Ulla Hellstrand Tang2,3*

The Foot and Ankle Online Journal 12 (3): 5

A vital role for any society is to deliver health care considering: 1) the planetary boundaries, 2) the complexity of systems and 3) the 17 sustainable development goals (SDGs). The aim is to explore the feasibility of a method to quantify the sustainability effects in health-care services. A toolbox was explored in the prevention and care of foot complications in diabetes. People with diabetes run the risk of developing foot ulcers and undergoing amputations. Three relationships between ecosystems and human health and health-care systems were identified as: (i) The economic resources for health care have previously appropriated ecological resources in the economic process. (ii) Health-care systems consume natural resources. (iii) Ecosystems and the landscape affect human well-being. Some types of landscape support human well-being, while others do not. This category also includes the impact of emissions on human health. Diabetes is one of the non-communicable diseases with high mortality and foot complications. With health-promoting interventions, the risk of developing foot ulcers and undergoing amputations can be halved. The toolbox that was used could manage the complexity of systems. Several of the 17 SDGs can be calculated in the prevention of complications in diabetes: quality of life improves, while the costs of healthcare and the burden on the economy caused by people not being able to work decrease. The appropriation of natural resources and the wasted assimilated capacity for the same welfare level decreases, thereby offering an option to deliver health care within the planetary boundaries. 

Keywords: healthcare, sustainability, diabetes, diabetic foot, noncommunicable diseases, NCD, SDG, sustainable development goals

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0005

1 – Nolby Ekostrategi, Tolita 8, SE-665 92 Kil, Sweden stefan@ekostrateg.se
2 – The Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden
3 – The Department of Prosthetics and Orthotics, Sahlgrenska University Hospital, Gothenburg, Sweden.
* – Corresponding author: ulla.tang@vgregion.se


Achieving sustainable development from local to global level is challenging. One vital part is offering health care to patients in need. One unresolved question remains and that is how to ensure that healthcare is delivered within the planetary boundaries [1,2]. Health care should serve an increasing number of patients diagnosed with non-communicable diseases (NCD) and in need of prevention and care [3]. The intention is to minimise the negative consequences of the disease for the individual, society and the planet.

There is very little scientific research that presents approaches designed to measure the consequences of health care in the three dimensions of sustainability; ecological, economic and social. Tools such as analytical hierarchical processes have been used to manage and evaluate the complexity of the health-care system in relation to the social aspects using semi-quantitative measurements [4]. The authors Aljaberi et al encourage health-care professionals to collect data, in particular data on patient satisfaction, as a basis for further analysis of the sustainability dimension of health-care systems. However, two important dimensions, the ecological and the economic, were left out of their analysis. The definition of sustainability that the authors used was put forward in 1992 by the International Institute for Sustainable Development in conjunction with Deloitte & Touche and the World Business Council for Sustainable Development: “For the business enterprise, sustainable development means adopting business strategies and activities that meet the needs of the enterprise and its stakeholders today, while protecting, sustaining and enhancing the human and natural resources that will be needed in the future” [5]. Twenty-three years later, in 2015, the UN approved the 17 Sustainability Development Goals (SDG) to secure a life for future generations on our planet, not only limited to the business enterprise but also including all aspects of life [6]. 

A substantial percentage of Gross Domestic Product (GDP) funds health-care systems. With well-functioning health care, the benefits to the individual and to society are substantial. Dealing with sustainability means dealing with complex systems and complexity. The complexity is expressed in the 17 sustainable goals the UN approved in 2015 [6]. At national level, Sweden manages the 16 Swedish national environmental quality objectives [7]. The systems in which sustainability is an issue are typically complex. To a significant degree, their complexity stems from the fact that life, bios, is a vital system-defining element. No system of importance for ecological, economic or social sustainability is possible, if we assume life outside the borders of the system. This information is fairly general. Is it necessary? The OECD made an important contribution to the definition of sustainable development and how to achieve it [8]. Two of the main problems that were identified were the implementation gap and knowledge gap respectively. Despite knowing fairly well how policies supporting sustainable development should be designed, implementation is at a low and varying level [1]. In the 2000s, some authors [9-13] concluded that the implementation gap and the closely related knowledge gap were caused to a substantial degree by inappropriate analytical and management tools. 

With life as a crucial system element, it is clear that all processes are driven by a flux of energy by which quality is degraded. The sum of energy is constant, while the quality of energy is degraded. From an energy perspective, the system is a linear one. 

Cells, organs, individuals and ecosystems represent different system levels in biological and ecological systems. Feedback loops at each of these levels and between them are important for the efficient use of available resources [14, 15]. The linear flux of energy with quality drives loops of matter. These reinforcing loops may include a number of system levels, as well as all three sustainability dimensions. This results in systems with mutual dependence between system levels and the three sustainability dimensions. With the existence of thresholds, and the nature of interconnections, the system typically has features such as thresholds, irreversibility and resilience. The knowledge gap and demand for analytical tools that takes account of thresholds, irreversibility and resilience has been addressed by the Rockefeller Foundation-Lancet Commission on planetary health [1]. 

Within life sciences, irreversibility is easily understood. The process from living to dead cannot be reversed. Resilience is a phenomenon that requires some effort to understand. A resilient system is able to withstand stress from internal and external sources without changing its character. If the source of stress is removed, it returns to its original status. Systems that are not resilient are pushed away by internal and/or external sources from the domain of an operating balance space or point, into a phase of rapid, unpredictable change. Its system conditions then experience rapid, catastrophic changes. Some important considerations:

  1. A change in a well-defined part of a system may affect a hierarchy of sustainability goals from low to high system levels in the ecological, economic and social dimensions
  2. Instruments from mathematics, such as differential functions and linear and non-linear algebra, are of importance in analytical and management tools supporting sustainable health care. 

With a multitude of goals in different dimensions and system levels, there is a need for instruments that support the optimisation of utilised resources. With systems with reinforcing loops operating close to the borders of chaos, differential functions are tools that are able to extract order from chaos. 

As mentioned before, the OECD found that the understanding of what sustainable development is and how to achieve it was well understood [8]. In spite of this, policies for sustainable development that were in place were on a low, uneven level. The OECD expressed great concern about this and related it to two closely related obstacles they called the implementation gap and the knowledge gap. 

These gaps reflected a broken connection between 

  1. A general understanding of what sustainable development is and the policies needed to promote it, expressed in fields and policy contexts such as classic economic theory back to the 18th century, agricultural sciences as living knowledge until the Second World War, system ecology and ecological economics from around 1990, the UN Millennium Development Goals [6], the OECD [8], the Millennium Ecosystem Assessment [16] and the Economics of Ecosystems and Biodiversity [17], on the one hand, and
  2. Instruments and concepts in common practice with the aim of putting sustainable development in place, on the other hand [10]. 

Typical instruments and concepts in (2) are life cycle assessments, in accordance with the ISO 14 001 system, the Best Available Techniques (BAT) principle in the Integrated Pollution Prevention and Control Directive in the EU, the Integrated Production Policy from the EU Commission and a number of other policies from the same scientific ground, suffering from the same drawbacks [10]. As these concepts and tools are derived from engineering sciences, they do not express the competence relating to systems where life, bios, defines system characteristics. Their “default solution” when managing the complexity of life, e.g. in the understanding of the impact of the use of natural resources and the emissions in biological and ecological systems actually affected by production, is to assume that this complexity does not exist [9, 10, 12, 13].

Within agricultural and forestry science and practice, tools that are able to manage this complexity have emerged over hundreds of years of theoretical development and of trial and error in practice. A similar development has been seen in system ecology and economic theory during the last few decades. A combination of contributions from agricultural sciences, forestry sciences, system ecology, integrative assessments, applied environmental sciences and economic theory at micro and macro level offers a solution to the implementation gap by resolving the challenge, in everyday actions, of managing complex real-world systems, while being aware of and respecting their genuine complexity due to life as a defining system characteristic. A new approach to calculating the sustainability effects in health care is needed with criteria as mentioned above. An approach of this kind considers the planetary boundaries, the three dimensions of sustainability and the complexity of ecosystems. The aim of the article is to present a new approach to measuring sustainability in health care, applied to the prevention of foot complications in diabetes.

Method

Conceptual model

Tools and methods that considered the planetary boundaries, the three dimensions of sustainability and the complexity of ecosystems were chosen. The toolbox originates from a variety of fields. For example, they supported sustainable animal production systems; sustainable industrial production systems; effective policies to minimise health hazards associated with cadmium fluxes in food systems; milk consumption and the human health impact; physical planning for sustainable attractiveness at local and regional level; sustainable local, regional and national development; the development of certification schemes such as ISO 14 001 to contribute more effectively to improving the status of ecosystems actually affected by production and consumption; the development of public procurement in favour of growth, employment and a better environment in accordance with national environmental objectives [9, 10, 12, 13, 18-26]. 

In what follows, our approach that supports the management of health-care systems in a sustainable society is presented. The accuracy of these instruments is investigated and applied to the prevention of foot complications in diabetes. The effects on the individuals living with diabetes is dramatic, with a lifetime risk of 25% that a foot ulcer will develop, a threatening reality for the 425 million people living with diabetes [27]. Every thirty minutes, an amputation takes places on the planet due to diabetes [28]. People with a lower socioeconomic status are more likely to develop complications such as cardiovascular disease and/or foot ulcers and amputations [29-31]. This means that people already struggling for their lives and surveillance will be marginalised, more vulnerable in the presence of foot ulcers and amputations. Their health-related quality of life will decrease [32-34].

The article presents a new approach that includes a conceptual model, a map, of the economic system in its ecological and social context [13]. From this map of the sustainability landscape, we are able to define different pathways by which we can improve human health and meet the demands of society. One way of estimating the impact of health care on the appropriation of natural capital, man-made capital, human capital and social capital is suggested. We use the diabetic foot as a case in this exercise. The hypothesis is that a set of these instruments developed with the aim of supporting the effective management of natural resources, with the emphasis on acreage-dependent sectors, is able to significantly improve the efficiency of health-care systems in meeting the 17 SDGs. The toolkit has five internally consistent instruments:

  1. A conceptual model of the GDP part of the economy embedded in its ecological and social contexts where stocks of natural, man-made, human and social capital are located [11].
  2. From the conceptual model, Biophysically Anchored Production Functions (BAPFs) are constructed showing how the GDP economy is dependent on nature and delivers resources for the fulfilment of human needs [13].
  3. An application based on the general features of Impredicative Loop Analysis by which the impacts in a hierarchy of sustainability sub-goals of a specific change in a specific production process can be evaluated [20].
  4. From BAPFs, ecological economic accounts (EEA) can be derived by which the sustainability performance of any system can be evaluated [10-12]. 

In what follows, the conceptual model of the economic system in its ecological and social context is presented in some detail. This supports the understanding of health care in a broader sustainability context. The conceptual model of the economy in its ecological and social context is presented, Figure 1 [12].

The model consists of three compartments, where the first refers to nature, to ecosystems providing natural resources and taking care of emissions. The second is the traditional economy where goods and services are produced from natural resources and inputs of labour and (traditional) capital. GDP measures the size of the output. The third is the social dimensions where the economic resources that are created to meet human needs, including health care. In all parts of the economy, emissions and waste return to nature. 

With some simplification, Compartment I represents nature, the ecological dimension of the economy, Compartment II represents the economic system, in the narrower sense in which we often discuss it, and Compartment III represents the social dimension of our economy. In reality, they are three closely integrated parts of our economic system.

Compartment I defines ecological restrictions in society, Compartment II provides the means, while Compartment III contains the objective: human well-being. 

From the perspective presented in Figure 1, the challenge of health care is to use appropriated economic resources as efficiently as possible in order to improve the health of the population. It focuses on preventing and/or compensating for the functional loss of the individual. With the efficient use of economic resources, the needs of the people suffering from illnesses are met, while the economic burden on the rest of the economy is kept down. This increases the demand for goods and services from households, which stimulates the economy. At the same time, the competitiveness between enterprises is increased, while everything else is equal. The efficiency measurement referred to implicitly is the ratio between the level of health in the population as the numerator and the economic cost of providing it as the denominator. With efficient health care, the level of health in the numerator is increased, while everything else is equal, which improves the life quality of individuals, thereby improving the social capital. With improved health, the productivity of the same individuals increases and the stock of human capital is thereby also improved.

Relationships between nature and health care

There are three types of relationship between health and health care and NC (Natural Capital) and NR (Natural Resources), as shown in Figure 1. 

  1. The appropriate economic resources are produced in the GDP economy where NR are upgraded to goods and services through the input of labour and capital, while, on the output side, potentially harmful emissions are generated. Health care thus appropriates NR embedded in the economic resources that are used and indirectly cause emissions that can harm human health and ecosystem health. This is the indirect support to service sectors such as health care from nature [35, 36]. 
  2. The health-care system also directly consumes NR, by using the energy needed to build and heat/cool the buildings, fuel the equipment and transport personnel and patients to and from hospitals [35, 36].
  3. The third type of relationship relates to the way ecosystems and the landscape affect human well-being. Some landscapes support human well-being, others do not. This category also includes the impact of emissions on human health. The first two relationships are connected to the appropriation of ecological resources in the production of health. The third relationship relates to the demands on health care to the needs to be met.

Through emissions and changes in land use, the capacity and quality of the life-support system of ecosystems are affected. In maps of Europe [10, 11] the effect on (i) expected human life expectancy due to the emission of particles into the air is presented, as well as (ii) the deposits of nitrogen exceed the assimilative capacity of ecosystems. The congruence in the geography of these human health and ecosystem health impacts is profound. 

The United Nations Environment Programme (UNEP) [37], in collaboration with the World Health Organisation (WHO), estimated that, in 2012, 12.6 million deaths, or 23 per cent of the total, were due to deteriorating environmental conditions [38]. Air pollution which, according to the UNEP, kills seven million people across the world each year, dominates. Of these, 4.3 million are due to household air pollution, particularly among women and young children in developing countries. There is an uneven distribution of deaths due to environmental deterioration, with the highest proportion of deaths attributable to the environment in South-East Asia and in the Western Pacific (28 per cent and 27 per cent respectively). The percentage of deaths attributable to the environment is 23 per cent in sub-Saharan Africa, 22 per cent in the Eastern Mediterranean region, 11 percent and 15 per cent in OECD and non-OECD countries in the Americas region and 15 per cent in Europe.

In the case of the diabetic foot, the transport of personnel and patients to and from providers of health care consumes energy and causes a multitude of emissions, harming the health of ecosystems and of humans. The emissions from hospitals should be considered. Health-care services located in areas stressed by high emission rates have a greater negative impact on human health compared with health-care services localised in areas with forests and land. Forests and land assimilate emissions [10, 39]. 

Non-communicable diseases (NCDs) are a group of diseases with a substantial impact on health [3].They kill 41 million people each year. Cardiovascular diseases account for most NCD deaths, or 17.9 million people annually, followed by cancers (9.0 million) and respiratory diseases (3.9 million). Tobacco use, physical inactivity, the harmful use of alcohol and unhealthy diets all increase the risk of dying from an NCD. The facts in the UNEP [37] and the WHO [38] imply that environmental issues are a substantial category of factors causing NCDs. This is supported by Lim et al. [40].

Health care and Agenda 2030 with 17 SDGs

Society can work through three major pathways to improve human health; traditional health care when illness is present, preventing illnesses by lifestyle changes within the population and by upgrading the quality of the environment and life-support systems. Odum [15] describes in detail the life-support systems of ecosystems, providing the physiological necessities for all life. In 2015, the UN [6] approved 17 SDGs. They form the basis of Agenda 2030. The overall objective of County Administrative Boards in Sweden, the regional representation of the national government, is to support the implementation of the 17 SDGs at regional level, in each county. The first paragraph in the task assigned to them is, at regional level, to contribute to sustainable, enduring solutions. The second is to contribute to the implementation of Agenda 2030 [41]. In Sweden, there is also a system of 16 environmental quality objectives [7]. Their role is to lay the environmental foundation for economic and social development within affected ecosystems carrying capacity limits. They agree well with the 17 SDGs from the UN with their foundation in the need for ecological sustainability as a prerequisite for economic and social sustainability. The recommendation from the UNEP [37] to reduce the number of deaths due to environmental deterioration reflects the purpose of the UN’s 17 SDGs. 

The presented toolbox supports policies that improve (i) health, by lowering the environmental burden on the ecosystem and human health, and (ii) diet patterns and physical activity, for example, to benefit both ecosystem health and human health, thus lowering NCDs. 

In what follows, an approach is presented in which the capacity of the toolbox to help health-care systems to comply with the 17 SDGs and the Swedish environmental quality objectives is tested. We do this using the case of diabetes and the prevention of diabetic foot ulcers (DFU).

Costs associated with diabetes and the diabetic foot

From 1980 to 2014, the prevalence of diabetes rose by a factor of 3.9, to 422 million people in 2014 [42]. In 1980, 4.7% of adults had diabetes and, in 2014, it was 8.5%. The rate of the increase in diabetes is highest in low-income and middle-income countries. If we add up the effect of diabetes and high blood glucose, 3.8 million deaths were related to these causes in 2012 [43]. The social and economic costs of diabetes to the individual and to society are therefore significant. Lowering the prevalence of diabetes will improve social and human capital (see Figure 1) and support a number of the 17 SDGs. 

A healthy diet, regular physical activity, maintaining a normal body weight and avoiding tobacco use are ways to prevent or delay the onset of diabetes type 2. For patients with diabetes it is important to maintain good function in the feet and in the lower extremities. 

The cost of the treatment of DFUs is substantial. In one study with data from Sweden, the span was 993-17,519 US$ [44, 45]. Table 1 presents estimates of treatment costs for diabetic foot ulcers at regional, national and global level [46]. 

Treatment costs US$ 2015
Patients, no Per patient Total, millions
Region Västra Götaland 3,000 5500 16.5
Sweden 20,000 5500 110
Global 20,000,000 5500 110000

Table 1 Estimated regional, national and global costs for treating DFUs in 2015. The equivalent of 5,525 US$ of 2015 converted from figures from 1990 per treatment of DFUs (5000 US$) was originally provided by Apelqvist et al. (1995) and refers to Sweden. Available 2018-07-12. http://www.historicalstatistics.org/Currencyconverter.html. 

Region Västra Götaland is one of the counties in Sweden. The estimated cost relates to the treatment of DFUs not infected or in need of intervention due to artery disease. The estimate is therefore conservative. We assume the same cost at regional level in Sweden (Västra Götaland) and global level as well. The estimate agrees well with the figures from Prompers et al [47], presenting estimates at European level, suggesting that the estimate is relevant at international level as well. 

The prevalence of DFUs is set at 5% among patients with diabetes [48]. The estimate is based on a population-based annual incidence of DFUs of 1.0-7.2% [49-53]. The number of patients with diabetes in Västra Götaland, in 2015, was approximately 60,000, in Sweden 400,000 [54] and globally 400 million people [55].

Results

By using the example of DFUs and the need for early prevention and treatment as an example, we shall now outline how the principles presented in previous parts can be considered in everyday practice in health care. We, therefore, present a proposal for ways of operationalising the UN’s 17 SDGs in health-care systems from the level of individual treatment to aggregated effects regionally, nationally and globally.

Of the population of people suffering from diabetes, it is estimated that 50% are in need of preventive foot care. This is based on the presence of the risk factor of loss of protective sensation, which can be as high as 50% in patients with diabetes [46]. Using early monitoring, patients at risk are identified, enabling intervention at an early stage [56]. Promising results show a reduction in the amputation rate of 40% to 60% [57] and DFUs of 50% [58]. Halving the presence of small DFUs leads to a reduction in ulcers that might develop into severely infected ulcers and amputations. 

One part of early treatment is the provision of insoles from a Department of Prosthetics & Orthotics (DPO) [59]. Insoles reduce the risk of pressure-induced DFUs [58, 60]. Insoles can be prefabricated or custom made or traditionally made [46]. Assume that we have custom-made insoles. Two visits to a health-care provider are needed. The costs associated with this solution are:

  • Time appropriated by
    1. The patient
    2. The staff at the health-care provider
  • Energy (with quality) consumed for
    1. Transportation to and from the health-care provider
    2. Heating of buildings and for the production of insoles 
  • Emissions from energy consumption potentially harming human and ecosystem health. 

The time appropriated by patients can be leisure time, or times when the patient would otherwise have worked, contributing to GDP.

The energy cost can be measured in both monetary and physical terms. Both are of interest. When measuring in physical terms, information is gathered that makes it possible to evaluate future risks and opportunities in relation to possible changes in the price of energy. The available amount of fossil fuels is limited. In 2015, fossil fuels provided 86% of the global energy budget [61]. 

The climate challenge calls for action which, in a fair number of decades, will eliminate the increase in greenhouse gases in the atmosphere [6, 7]. Energy consumption causes the emission of a spectrum of substances that affect the majority of the 16 environmental quality objectives in Sweden and those of the UN’s 17 SDGs that are related to emissions and their impact on ecosystems and human health. Regarding energy systems, we also have a range of aspects related to hydropower and nuclear power to consider, as well as contributions to climate change. Renewable fuels are of increasing importance for the supply of energy.

Taken together, the limitedness of non-renewable natural resources, fossil fuels, their dominance among energy sources in the economy from local to global level and the environmental and human health impacts of these energy sources and of hydropower and nuclear power all indicate a future, substantial transformation of the energy systems from local to global level. This transformation to future energy systems effectively supporting a sustainable society will cause a change in energy prices. 

Since 1998, there has been a substantial increase in the fixed level of global oil prices [10]. This may affect the outcome with regard to the rational localisation of future health care in the landscape. As a result, there are good economic reasons for health-care providers to be in control of their energy consumption in both economic and physical terms.

The time that each patient appropriates from the staff is time during which the staff are unable to support other groups of patients within budget restrictions. 

Figure 1 A conceptual model of the economy in its ecological and social contexts.

Assume that we have a solution where we can offer the same benefits to the patient with only one visit (the system with prefabricated insoles). If so, the above-mentioned costs can be cut by 50% per patient treated. On a regional, national and international scale, this would substantially improve the contribution to a number of ecological, economic and social sustainability goals.

So far, we have not dealt with the challenge of health-care systems that operate within affected ecosystems with capacity limits. The toolbox for sustainable development mentioned above [10] supports a solution to this challenge. It thus supports the emergence of health-care systems promoting Agenda 2030.

The production of ecosystem services from the life-support systems of ecosystems can be quantified. These systems are located in rural areas, in the so-called cultural and natural landscapes as defined within system ecology [15]. The contribution from Odum laid the scientific foundation for most of the work that has subsequently been devoted to the issue of ecosystem services and their importance for human well-being: the OECD [8], the Millennium Ecosystem Assessment [16] and the Economics of Ecosystems and Biodiversity [17].

Ecosystems are Compartment 1 in the model of the economic system in its ecological and social contexts in Figure 1. This is the ecological dimension of our economy and of our society. Using the same tools, the consumption of ecosystem services can also be quantified.

So, using the same tools deeply rooted in natural sciences, including agricultural sciences and system ecology, we are able to quantify the sustainable production of ecosystem services, as well as consumption. With this information related to the demand for and supply of ecosystem services, the human appropriation of ecosystem services can be adapted to affected ecosystems with capacity limits.

This suggests a way in which the appropriation of natural resources and the emissions related to the treatment of the diabetic foot are related to the area of ecosystems with the capacity to deliver natural resources and assimilate emissions. This suggests a methodological route to evaluate the pressure on nature from health-care systems and to adapt health-care systems and other socioeconomic systems to the carrying capacity of affected ecosystems.

Through this route, ecological and economic dependence between rural and urban areas can be visualised and policies that contribute to their mutual development in a sustainability context can be effectively implemented. 

Discussion

This paper presents a framework for measuring sustainability in health-care using a toolbox supporting the effective management of natural resources. Analytical tools evaluating the sustainability performance in health care in ecological, economic and social terms are a prerequisite for the management of health-care systems, in agreement with the UN’s 17 SDGs. Using a sustainability map, three types of relationship between ecosystems and human health and health-care systems were identified. 

  1. The economic resources needed to cover the cost of health care have previously appropriated ecological resources in the economic process, at the same time as good health care may reduce future economic costs and thereby the ecological resources that are appropriated. 
  2. Health-care systems consume natural resources.
  3. Ecosystems and the landscape affect human well-being. Some types of landscape support human well-being, while others do not. This category also includes the impact of emissions on human health. 

Diabetes, one of the NCDs, has a substantial impact on the health level of societies. In Sweden, around 20,000 patients with diabetes suffer from DFUs, while the global figure is 20 million people. With preventive interventions, the prevalence can be halved, saving 50 million USD in health-care costs in Sweden and 50 billion USD globally. 

Further research should preferably present details in ecological units, economic monetary terms and social terms from a real case for the two alternatives: the supply of insoles with one visit as compared with two visits to a DPO.

Effective, preventive interventions reduce the cost of health care, as well as the burden on the economy imposed by people who are not able to work. Life quality, i.e. social sustainability, is improved. The appropriation of natural resources and the waste of assimilative capacity for the same welfare level decrease. As a result, ecological, economic and social sustainability is improved – a prerequisite for development within the planetary boundaries.

Abbreviations

BAPF; Biophysically Anchored Production Functions, GDP; Gross Domestic Product, NC; natural capital, NCD; non-communicable diseases, NR; natural resources, SDG; Sustainable Development Goals, WHO; World Health Organisation, UNEP; United Nations Environment Programme

Acknowledgements

We are most grateful for the useful comments on the manuscript made by Professor Jon Karlsson, Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Gothenburg. The Department of Prosthetics & Orthotics at Sahlgrenska University Hospital, Gothenburg, Sweden, encouraged the project. Thanks to all co-workers at the department and to graphic designer Pontus Andersson.

Availability of data and materials

Not applicable.

Authors’ contributions

S.H and U.H.T wrote the main manuscript text. S.H. prepared Figure 1. U.H.T prepared Table 1. All the authors reviewed the manuscript.

Funding

This research was supported by by Stiftelsen Promobilia, Stiftelsen Skobranschens Utvecklingsfond, the Research and Development Council of the County of Göteborg and Södra Bohuslän, the Health & Medical Care Committee of the Västra Götaland Region, Stiftelsen Felix Neubergh, Stiftelsen Gunnar Holmgrens Minne, IngaBritt & Arne Lundbergs Forskningsstiftelse, Adlerbertska forskningsstiftelsen, Diabetesfonden, the Gothenburg Diabetes Association (Inger Hultman med fleras fond and Utvecklingsfonden) and Sveriges Ortopedingenjörers Förening, Greta och Einar Askers Stiftelse and Hans Dahlbergs stiftelse för miljö och hälsa.

Competing interests

S.H. manages Nolby Ekostrategi but does not consider this to be a conflict of interest in this work. UT declares no competing interests.

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Chronic ulceration following surgical excision of a Morton’s neuroma due to an underlying arteriovenous malformation of the foot

by H Emmerson MBBS1, T Howard BMBS2*, M Wilkinson FRCS (Ortho)3, RS Ahluwalia FRCS (Tr & Orth)4

The Foot and Ankle Online Journal 12 (3): 4

An arteriovenous malformation (AVM) of the foot is a rarely encountered clinical pathology.  Arteriovenous malformations are most commonly found in the brain and lungs, and when found in the lower limbs, are usually in the pelvis or thigh and not the foot or ankle.  We describe a rare malformation that complicated surgical removal of a Morton’s neuroma, with chronic ulceration and failed wound healing. Successful treatment with conservative measures ensured full recovery. We believe all health care professionals should be aware of this pathology and consider it as a cause of delayed healing.

Keywords: arteriovenous malformation, foot, chronic ulceration, delayed wound healing

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0004

1 – Trauma & Orthopaedics, King’s College Hospital, London
2 – Foundation Doctor, Trauma & Orthopaedics, King’s College Hospital, London
3 – Trauma & Orthopaedics, King’s College Hospital, London
4 – Consultant Surgeon, Trauma & Orthopaedic, King’s College Hospital, London
* – Corresponding author: Theodore.howard@nhs.net


We present the case of a 38-year-old bus driver who presented with a non-healing ulcer of the left foot following the removal of a Morton’s neuroma 10 months prior at a community allied medical institution unrelated to ours. Initially, he presented in the community with ongoing focal pain in the 2nd and 3rd metatarsophalangeal joint web-space and was treated conservatively. With no resolution in pain and a slow growing mass on the dorsum of his left foot, an ultrasound scan was undertaken which confirmed a 10mm neuroma in the second web space. Two injections of steroid/local anaesthesia provided temporary relief but were subsequently followed by surgical removal of the neuroma. The wound never healed with constant ooze and further surgical debridement was undertaken in the community, accompanied by multiple courses of oral antibiotics. He had been unable to work since the neuroma removal and at 10 months post-removal he was referred for review at our institution.

He now revealed that he had had a right hip replacement at age 34 for traumatic osteoarthritis, and left testicular vein embolisation for varicocele. Physical examination of the left foot revealed a bleeding 0.5×0.5cm ulcer on the dorsum between the 2nd and 3rd web spaces (Figure 1). A dusky, pulsatile mass of 3cmx3cm was noted underlying the ulcer with surrounding hemosiderin deposition and a palpable thrill was present.  Neurovascular and musculoskeletal examination were unremarkable and there were no abnormalities to the right foot.

Figure 1 Photographs of skin appearances of the left foot 1 week after presentation. Dorsum – visible features are a healing ulcer between the 2nd and 3rd digits, hemosiderin deposition and engorged veins. Sole – ulceration and a dusky swelling are evident.

Figure 2 CT angiogram of lower limbs demonstrating distended veins throughout the left lower limb with a leash of abnormal vessels from the knee to the foot.

Figure 3 T1-weighted MR sagittal image of the left foot demonstrating the nidus of the AVM with an engorged draining vein.

A Doppler scan was performed which detected fully patent arteries throughout the left limb with triphasic flow with a prolonged diastolic component, suggestive of hyperaemia. A computed tomography (CT) with contrast and magnetic resonance angiogram (MRA) confirmed a low flow vascular malformation (Figures 2-4).  These images revealed an enhancing soft tissue mass lesion with feeding vessels overlying the left second and third metatarsals, extending into the plantar soft tissues and a leash of abnormal vessels from the knee (Figure 2).

Angiography was undertaken demonstrating a large arteriovenous malformation (AVM) around the second toe with multiple feeding vessels (Figure 5).  This was deemed unsuitable for selective endovascular embolisation due to congestion. The patient was successfully treated with limb elevation and Class 1 compression stockings: three months later the patient reported great clinical improvement and had returned to work. 

Figure 4 [A] T1-weighted MR axial image demonstrating signal void in the engorged draining vessel (arrowed). [B] MR angiogram post-contrast demonstrating multitude of vessels (artefact present at digits).

Discussion

We demonstrate the presentation of an incidental rare underlying pathology complicating a simple procedure. A high degree of clinical suspicion is needed to avoid missing this diagnosis.   Although AVMs do occur in the lower limbs, there are very few case reports in the literature of malformations arising so distally, in the foot. Therefore this is an unusual pathology that all foot and ankle practitioners should be aware of and should understand its management, as conservative treatment can provide a low cost and highly efficacious treatment.

An AVM is an abnormal collection of blood vessels allowing direct communication between arteries and veins.  The incidence is between 1-10/100000 and they are commonly found in the brain & trunk [1] and arise from congenital malformations, trauma and degenerative vascular diseases. Their growth is exacerbated by local trauma and hormonal changes, such as puberty and pregnancy [2].  Most are isolated pathologies, but multiple malformations are associated with syndromes such as Osler-Weber-Rendu, Sturge-Weber and Klippel-Trenaunay [3].  

The symptoms are dependent on locality and size and most remain small and clinically silent [3].  Symptoms occur due to effects on surrounding structures, such as bone, muscle and soft tissue and include pain, swelling, ulceration and deformity, and can be debilitating.  If left untreated, chronic ulceration may cause haemorrhage or necrosis. 

Clinical presentation can include a pigmented lesion, or birthmark, visible pulsation, or palpable thrill and engorged veins (varicosities).  Due to the local skin appearances, and rarity, the diagnosis can be mistaken for dermatological pathologies such as angiodermatitis or Kaposi’s sarcoma, or vascular tumours and chronic infection [3,4]. In this case the prolonged time to heal, ongoing ooze and bleeding from the surgical site were the findings on presentation. It is unclear whether the AVM preceded surgery but certainly was recognisable in the form of a pulsatile mass at presentation to our clinic. Surgical intervention for neuroma excision may have exacerbated the AVM, given its extensive nature.  

Initial investigation includes radiography to evaluate surrounding bony structures for erosion [3]. Color Doppler ultrasonography is a useful initial non-invasive investigation for evaluating location, size and flow of the AVM.  CT with angiography will visualise bone and tissue involvement, calcification, the presence of thrombi and size. However, magnetic resonance imaging is particularly important in providing imaging of adjacent soft tissue structures that can be involved.  Using dynamic gradient pulse sequences in MR is useful in evaluating whether the lesion is high flow or low flow [5].

Interventional therapies include ligation of feeding vessels, surgical excision, sclerotherapy or embolisation with coils/particles [6-8].  However, as demonstrated here, low-flow AVMs respond well to conservative measures, such as limb elevation and graded compression stockings.

This case is unusual as to why an extensive AVM should arise.  It is quite possible the surgical intervention for neuroma excision gave rise to the AVM or exacerbated the AVM, but given its extensive nature, it would most likely have been present prior to surgery.  It demonstrates the importance of appropriate clinical examination and high suspicion when delayed healing has complicated a simple wound. It highlights the importance of understanding wound pathology and the role of simple clinical management to healing.

References

  1. Kunze B, Kluba T, Ernemann U, Miller S. Arteriovenous Malformation: An unusual Reason for Foot Pain in Children. The Foot and Ankle Online Journal 2009; 2 (12): 1
  2. Huang JT, Liang MG. Vascular Malformations. Paediatric Clinics North America 2010; 57:1091-110
  3. Yu G, Brarens R, Vincent, A. Arteriovenous Malformation of the Foot: A Case Presentation. Journal of Foot & Ankle Surgery. 2004; 43(4):252-259.
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Peroneal tendinopathy in resolved Charcot foot – management with foot orthoses: A case report

by Joshua Young BSc.(Hons), MBAPO Orthotist1*

The Foot and Ankle Online Journal 12 (3): 3

This case report presents an occurrence of painful peroneal tendinopathy in a high risk diabetic foot following Charcot neuroarthropathy, managed using foot orthoses. Self-reported pain intensity was assessed using the 11-point numeric pain rating scale (NRS-11). Peak plantar pressures were assessed using the Pressure Guardian system for three conditions: 3.2mm poron inlay (control), custom foot orthosis, and custom foot orthosis with lateral wedge. Following addition of lateral wedging to the existing foot orthoses, pain reduced to a satisfactory level for the subject. Plantar pressure measurement showed that the addition of lateral wedging did not increase peak plantar pressures above 200kPa, a proposed dangerous level of pressure. Additionally, the foot orthoses still successfully reduced peak plantar pressures to below 200kPa, compared to walking without them. Peroneal tendinopathy should be considered as a possible cause of lateral ankle pain in neuropathic diabetic feet. Lateral wedging can be considered as one option to reduce pain in peroneal tendinopathy, and may not compromise the protective effect of foot orthoses in high risk feet.

Keywords: Charcot, foot, peroneal, tendinopathy, orthoses, insoles

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0003

1 – Roehampton Rehabilitation Centre, Queen Mary’s Hospital. St George’s University Hospitals NHS Foundation Trust, London, UK.
* – Corresponding author: Joshua.Young1@nhs.net


Pain can be present even in a diabetic foot with neuropathy. Causes of pain in this group could include painful diabetic neuropathy [1–3]⁠ and Charcot neuroarthropathy (CN) or ‘Charcot foot’ [4]⁠. The cause of the pain should be determined to inform appropriate management.

Tendinopathy may also occur and cause pain in the neuropathic diabetic foot. There is a higher risk of tendinopathy in diabetes [5–7]⁠. Chronic ankle instability or ‘hind foot varus’ have been suggested as predisposing factors to developing peroneal tendinopathy [8]⁠. In theory the ground reaction force on an inverted heel deviates medially, causing an increased ankle inversion moment which must be opposed by the peroneal muscles. A more supinated foot may develop as a result of CN [9,10]⁠.

It has been proposed that the conservative management of peroneal tendinopathy may include protection, relative rest, ice, compression, elevation, medications, and rehabilitative exercise modalities (PRICEMM) in addition to foot orthoses and strengthening of ankle evertors [11]⁠. There is limited evidence on the role of foot orthoses in peroneal tendinopathy. Some work has shown that foot orthoses alter peroneal muscle activity in runners with overuse injury symptoms [12] and in adults with chronic ankle instability [13]. A foot orthosis with a 10 degree lateral wedge has been shown to increase pronation at the rearfoot and reduce the ground reaction force magnitude, suggesting increased shock attenuation by the foot and ankle[14]⁠. This case study presents a case of painful peroneal tendinopathy, which developed in a foot following CN and was subsequently managed using foot orthoses (FOs). The CARE guidelines for reporting of case studies was followed [15]. Written informed consent was obtained for the publication of the materials in this article.

Methods

The subject was a 60 year-old male with type 2 diabetes with a history of CN affecting both feet. The CN resolved 8 months previously. There was a history of superficial ulceration (Texas grade A1) [16]⁠ to the left plantar 1st metatarsal-phalangeal joint and 1st tarso-metatarsal joint, both resolved for 8 months with the use of custom foot orthoses at the time of presentation with a primary concern of right foot pain.

Clinical Findings

There was sensory neuropathy, with only 1 out of 10 sites tested with a 10g monofilament being detected (Plantar 1st and 3rd toes, plantar 1st, 3rd and 5th metatarsal-phalangeal joints bilaterally). Circulation was good with triphasic posterior tibial pulses. Passive joint ranges of motion at the foot and ankle was generally good bilaterally except reduction in midtarsal movement on the left, and reduced extension at the left 1st metatarsal-phalangeal joint (45 degrees) compared to the right (60 degrees). Foot posture was rated using the foot posture index (FPI-6)[17]⁠ as +9 on the left and +3 on the right, indicating a highly pronated foot on the left and a relatively less pronated foot on the right (Figures 1 and 2). The FPI-6 differential of 6 points exceeds both normal values for foot asymmetry and mean asymmetry reported in a CN group [10,18]. The patient presented reporting a 6 week history of right foot pain, indicating the lateral ankle. This developed despite an existing 6mm lateral flare/float addition to the right heel, intended to resist ankle inversion. Pain intensity was reported as 7/10 on the numeric rating scale (NRS-11). 

Diagnostic Assessment

Palpation of the peroneal tendons posteriorly to the lateral malleolus reproduced the pain experienced during walking. A portable ultrasound system was used by the author at this stage, indicating some fluid in the peroneal tendon sheath. 

Figure 1 Left and right feet (anterior and posterior view).

Figure 2 Lateral radiographs of left and right feet.

Figure 3 Cross sectional ultrasound image of peroneus longus showing fluid within the tendon sheath.

Figure 4 Cross sectional ultrasound image of peroneus longus and brevis using power Doppler to show hyper vascularity in the tendons.

Figure 5 Left and right foot orthoses, plantar view.

Figure 6 Right foot orthosis, posterior view.

Referral to radiology for a definitive evaluation was made, which confirmed the diagnosis of peroneal tendinopathy (Figures 3 and 4). The report identified fluid in the common peroneal tendon sheath, in keeping with tenosynovitis, and marked thickening of the peroneus brevis tendon at the insertion, in keeping with tendinosis.

Therapeutic Intervention – Orthotic Prescription

The existing FOs consisted of a 3mm thick base with 50 shore A Ethylene-vinyl acetate (EVA) at the proximal half and 30 shore A EVA at the distal half. There are ‘plugs’ under the right cuboid region, left 1st metatarsal-phalangeal joint and 1st tarso-metatarsal joint where the base material has been replaced with grey poron (Poron 4000, Algeos, Liverpool). 6mm grey poron is used as a top cover, giving a total 9mm base thickness (Figure 5).

Lateral heel wedging (3 degrees) was added to the existing foot orthoses, however the patient reported no immediate change. A further 5 degrees (8 degrees total) was added on the same day – the patient reported that the pain reduced to 1/10 immediately.

Outcome 

At review 8 weeks later, the patient reported that the pain had reduced to 0/10 24 hours following the addition of the lateral wedge. However, 72 hours after the addition of the lateral wedge the pain returned to 4/10. At this stage, the lateral heel wedge was increased to 12 degrees (Figure 6) and extended to the midfoot. The patient again reported an immediate reduction from 4/10 to 0/10.

To ensure that the aggressive wedging added was not causing high pressures in other areas of the foot, in-shoe pressure measurement was used. Comparisons were made with a 3mm poron inlay only, the custom foot orthosis only, and the custom foot orthosis with 12 degree wedge (Table 1). 

Sensor location Peak pressure (kPa) – 3mm poron inlay  Peak pressure (kPa) – custom foot orthosis Peak pressure (kPa) – custom foot orthosis with 12 degree lateral wedge
Lateral plantar heel 71 28 32
Medial plantar heel 69 18 8
Lateral plantar midfoot (Charcot deformity) 244* 94 133
Plantar 1st metatarsal-phalangeal joint 28 33 31

Table 1 Peak plantar pressures (*Indicates a peak pressure value exceeding the proposed dangerous level of 200kPa).

Considering 200kPa as a dangerous level of pressure [19], the custom FO reduced the lateral plantar midfoot (Charcot deformity) pressure to below this level. Following the addition of the lateral wedge, all plantar pressures tested remained below the 200kPa level. Some increase in pressure at the lateral midfoot was measured, reflecting the extension of the wedge to the midfoot. Slight increase in pressure was seen at the lateral heel, which seems to indicate that the centre of pressure was moved laterally by the lateral heel wedge.

At a second review appointment 6 weeks later, the pain had returned back to 4/10. The patient declined any other management and was happy to continue using the laterally wedged foot orthoses. At a third review 8 weeks later, the pain was slowly reducing and now rated as varying between 2/10 and 4/10.

Discussion

This case study illustrates a relatively successful outcome in reducing pain associated with peroneal tendinopathy, using FOs only. The initial pain level of 7/10 was reduced by at least 3 points, which exceeds reported minimal clinically important difference (MCID) values [20]. Of interest is the fact that the patient reported marked immediate effects following the addition of lateral wedging to the existing FOs. This initial effectiveness tended to reduce over time, with pain levels increasing again. One possible explanation for this reduction in initial success may be some compression of the orthoses, which were not made with rigid plastic. The outcome may have been more successful if accompanied by other approaches such as physical therapy, however in this case due to patient preference only one approach was used.

Following initial use of a lateral wedge at the heel only, longer term reductions in pain were achieved by extending the wedge to the midfoot. The extension of the wedge to the midfoot has a logical anatomical basis, as the insertion of the peroneus brevis is distal to the heel, at the base of the 5th metatarsal. It is therefore logical to apply the opposing force in this area. The angle of the lateral wedge also needed to be increased to maintain pain reduction. A systematic effect of altering heel wedge geometry on external forces acting on the foot has been shown by Sweeney [21]⁠ although this relates to medially positioned wedging. The need for these small adjustments highlights the importance in this case not just of selecting an appropriate modification, but also the size and location of the modification. 

Applying relatively aggressive wedging to orthoses for feet at risk of ulceration may be controversial, as traditional approaches to designing FOs for high risk feet often focus on accommodation, rather than altering function of the foot. In this case, use of pressure measurement enabled verification that pressure levels were brought below 200kPa by the FOs, and that this reduction persisted despite the addition of a large lateral wedge. This indicates that aggressive FO designs may be safely used in high risk diabetic feet. However pressure measurement should ideally be used to assess the effectiveness and safety of any orthotic prescription in the context of a high risk foot.

The cause of the tendinopathy in this case is uncertain. The right foot and ankle may have become more prone to inversion as a result of changes to the bony architecture following CN. This may have in turn caused increased inversion moments at the rearfoot, and hence more stress on the peroneal tendons. Neuromuscular control may also be a factor, as the timing of muscle activation has been shown to be altered in diabetic patients [22]⁠⁠. 

This case report has illustrated that lateral wedging up to 12 degrees may be safe and not compromise the protective function of a FO in a high risk diabetic foot. Clinicians should consider peroneal tendinopathy as a possible cause of lateral ankle pain in neuropathic diabetic feet. Clinicians may consider orthosis wedging as one option to reduce pain in peroneal tendinopathy, in addition to other approaches.

References

  1. Davies M, Brophy S, Williams R, Taylor A. The prevalence, severity, and impact of painful diabetic peripheral neuropathy in type 2 diabetes. Diabetes Care. 2006;29(7):1518-22.
  2. Young MJ, Boulton AJ, Macleod AF, Williams DR, Sonksen PH. A multicentre study of the prevalence of diabetic peripheral neuropathy in the United Kingdom hospital clinic population. Diabetologia. 1993;36(2):150-4.
  3. Galer BS, Gianas A, Jensen MP. Painful diabetic polyneuropathy: epidemiology, pain description, and quality of life. Diabetes Res Clin Pract. 2000;47(2):123-8.
  4. Armstrong DG, Todd WF, Lavery LA, Harkless LB, Bushman TR. The natural history of acute Charcot’s arthropathy in a diabetic foot specialty clinic. Diabet Med. 1997;14(5):357-63.
  5. Lui PPY. Tendinopathy in diabetes mellitus patients-Epidemiology, pathogenesis, and management. Scand J Med Sci Sports. 2017;27(8):776-787.
  6. Batista F, Nery C, Pinzur M, et al. Achilles tendinopathy in diabetes mellitus. Foot Ankle Int. 2008;29(5):498-501.
  7. Ranger TA, Wong AM, Cook JL, Gaida JE. Is there an association between tendinopathy and diabetes mellitus? A systematic review with meta-analysis. Br J Sports Med. 2016;50(16):982-9.
  8. Selmani E, Gjata V, Gjika E. Current concepts review: peroneal tendon disorders. Foot Ankle Int. 2006;27(3):221-8.
  9. Pinzur MS, Schiff AP. Deformity and Clinical Outcomes Following Operative Correction of Charcot Foot: A New Classification With Implications for Treatment. Foot Ankle Int. 2018;39(3):265-270.
  10. Young J. Foot shape and asymmetry in Charcot foot – assessment using the foot posture index (FPI-6). J Am Podiatr Med Assoc. [In Press]
  11. Simpson MR, Howard TM. Tendinopathies of the foot and ankle. Am Fam Physician. 2009;80(10):1107-14.
  12. Baur H, Hirschmüller A, Müller S, Mayer F. Neuromuscular activity of the peroneal muscle after foot orthoses therapy in runners. Med Sci Sports Exerc. 2011;43(8):1500-6.
  13. Dingenen B, Peeraer L, Deschamps K, Fieuws S, Janssens L, Staes F. Muscle-Activation Onset Times With Shoes and Foot Orthoses in Participants With Chronic Ankle Instability. J Athl Train. 2015;50(7):688-96.
  14. Nester CJ, Van der linden ML, Bowker P. Effect of foot orthoses on the kinematics and kinetics of normal walking gait. Gait Posture. 2003;17(2):180-7.
  15. Gagnier JJ, Kienle G, Altman DG, et al. The CARE Guidelines: Consensus-based Clinical Case Reporting Guideline Development. Glob Adv Health Med. 2013;2(5):38-43.
  16. Armstrong DG, Lavery LA, Harkless LB. Validation of a diabetic wound classification system. The contribution of depth, infection, and ischemia to risk of amputation. Diabetes Care. 1998;21(5):855-9.
  17. Redmond AC, Crosbie J, Ouvrier RA. Development and validation of a novel rating system for scoring standing foot posture: the Foot Posture Index. Clin Biomech (Bristol, Avon). 2006;21(1):89-98.
  18. Rokkedal-lausch T, Lykke M, Hansen MS, Nielsen RO. Normative values for the foot posture index between right and left foot: a descriptive study. Gait Posture. 2013;38(4):843-6.
  19. Bus SA, Ulbrecht JS, Cavanagh PR. Pressure relief and load redistribution by custom-made insoles in diabetic patients with neuropathy and foot deformity. Clin Biomech (Bristol, Avon). 2004;19(6):629-38.
  20. Young J, Rowley L, Lalor S, Cody C, Woolley H. Measuring Change: an Introduction to Clinical Outcome Measures in Prosthetics and Orthotics [Internet]. 1st ed. Paisley: British Association of Prosthetists and Orthotists; 2015.
  21. Sweeney D. An investigation into the variable biomechanical responses to antipronation foot orthoses [Internet]. 2016 [cited 2018 Aug 11]. Available from: http://usir.salford.ac.uk/40365/1/Declan Sweeney PhD Thesis %28submitted%29.pdf
  22. Sawacha Z, Spolaor F, Guarneri G, et al. Abnormal muscle activation during gait in diabetes patients with and without neuropathy. Gait Posture. 2012;35(1):101-5.

The role of tinea pedis and onychomycosis prevention in diabetic education: A literature review

by Ebony Love DPM1, Tracey Vlahovic DPM1*, Lauren Christie DPM1

The Foot and Ankle Online Journal 12 (3): 2

The prevalence of individuals with diabetes has steadily been increasing, creating both a health and economic crisis world-wide.  Previous studies have suggested that foot fungal infections, including onychomycosis and tinea pedis, increase the risk of developing a diabetic foot ulcer. Through a thorough PubMed search, this article aims to review relevant literature relating to superficial fungal infections and patients with diabetes.  

Keywords: Tinea pedis, diabetes, onychomycosis, patient education

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0002

1 – Temple University School of Podiatric Medicine, Philadelphia, PA
* – Corresponding author: traceyvlahovicdpm@yahoo.com


The prevalence of individuals with diabetes has steadily been increasing, creating both a health and economic crisis world-wide [1,2]. Diabetic foot infections, one of the major complications associated with diabetes, have significantly contributed to both an increase in mortality and financial burden in the diabetic population. The incidence of diabetic foot ulceration has been reported in up to 19% of the diabetic population, which has been associated with lower limb amputation and mortality [3,4]. In the efforts to prevent these complications from occurring, patients with diabetic foot infections tend to have more frequent outpatient visits, increase frequency of visits to the emergency room, increased frequency and duration of hospital stays, and an increased need for home health care; further increasing the economic crisis of this disease [2].

Previous studies have suggested that foot fungal infections, including onychomycosis and tinea pedis, increase the risk of developing a diabetic foot ulcer [5,6,7]. Diabetics are 2.77 times more likely to develop onychomycosis compared to non-diabetics, negatively impacting their physical and physiological health [8,9]. If left untreated, onychomycosis and tinea pedis can lead to cutaneous injury and ulceration due to dystrophic, brittle nails penetrating the skin and/or interdigital or moccasin skin fissuring, especially in patients with neuropathy or peripheral vascular disease (PVD) [10].

Patient education is critical in diabetic foot care to help manage and prevent diabetic foot infections, other comorbidities, and mortality. The objective of this review is to assess the current literature on foot fungal infections in patients with diabetes as it relates to diabetic foot care education.

Methods 

A PubMed review of literature with keywords of tinea pedis and onychomycosis in patients with type II diabetes was reviewed.

Results 

The frequency of foot fungal infections is significantly higher in diabetics compared to non-diabetics. In a 2016 study, Oz et al., found that while elderly males are at an increased risk of developing onychomycosis regardless of whether they have diabetes, 14% of those in the diabetic group versus 5.9% of those in the control group had tinea pedis and/or onychomycosis [11]. According to Papini et al., in 2013, 69.3% of diabetics with a foot complication present with a foot fungal infection. Dermatophytes were the most common fungal species present, but non-dermatophytes, such as Candida albicans were also noted. Additionally, they found that diabetics with a previous toe amputation were significantly more likely to present with both tinea pedis and onychomycosis concomitantly. They concluded that specific treatment of the fungus involved is necessary for mycological cure to prevent diabetic foot complications, such as ulceration, loss of limb, and loss of life [12].

Another study by Gulcan et al., in 2014, found 25.3% of diabetic subjects mycologically had mycotic nails, out of the 161/321 diabetic patients who clinically presented with mycotic nails. Additionally, there was a significant association between onychomycosis and family history of the disease, BMI, longer duration of being diabetic, neuropathy, and retinopathy. They suggested that diabetic patients who have any of the risk factors found to be associated with onychomycosis in this study, should be properly educated diabetic and fungal infection education, to prevent the development of secondary lesions [13].

In addition to being more prevalent in the diabetic population, fungal foot infections occur in diabetics at a significantly earlier age compared to non-diabetics. In 2008, Legge et al., obtained scrapings from interdigital maceration of 40 diabetics and 40 non-diabetics. Of the 40% of samples collected that tested positive for fungal infection, patients in the diabetic group were on average 6.3 years younger than the non-diabetic group. They concluded that patients with diabetes may be more susceptible to developing tinea pedis at a younger age [14].

In 2017, Takehara et al., analyzed 30 patients with diabetes, 16 of which had tinea pedis, and found the number of times scrubbing between toes while washing with soap was significantly lower in subjects with tinea pedis compared to those who did not have tinea pedis. The number of times subjects scrubbed between toes with soap was also significantly lower in those who had difficulty reaching their feet. The authors suggested that each web space should be scrubbed 4-5 times for tinea pedis prevention and that proper education and intervention should be given to patients who have difficulty reaching their feet on more convenient foot washing positions [15].

It has well been known that foot fungal reinfection can occur from contaminated socks and sneakers. Broughton in 1955 found that individuals who wore cotton or wool socks were particularly susceptible to reinfection in hot, moist conditions, even after six wash cycles [16]. To reduce the risk of relapse, they suggested modifications and materials used to make socks and footwear and improved hygiene could potentially help.

Modifications to cotton socks have been found to have antifungal properties for diabetic patients. In 2012, Tarbuk et al., found modified cotton socks worn by diabetic subjects with active carbon, natural mineral, or zeolite had antimicrobial properties against Candida albicans after 15 washing cycles, unlike the pure cotton control. Modified cotton socks with zeolite additionally had antimicrobial properties to S. aureus. The authors concluded that the active carbon and mineral particles found in the modified cotton socks did not directly prevent microbial infection, but through creating a drier environment for the foot by absorbing more moisture, were able to prevent microbial growth in patients with diabetes [17].

Another treatment that has been shown to be beneficial in reducing fungal load is ultraviolet treatment of shoes of those infected with dermatophytes. Ghannoum et al., in 2012, found that ultraviolet treatment of shoes infected with dermatophytes was significantly effective in reducing fungal load in shoes. There was a 76.28% mean reduction of colony-forming units/ml of Trichophyton rubrum after 3 cycles of UV C radiation treatment. They suggested that by sanitizing shoes, it can stop the cycle of reinfection while being treated for fungal infection by other means and it can help prevent relapse [18].

Prophylactic application of topical antifungals in diabetic patients has also been suggested, given the potential complications that onychomycosis can cause in diabetics and the high reinfection relapse [19]. A study by Sigurgeirsson et al., in 2010, found that patients previously cured from onychomycosis who were prophylactically treated with amorolfine twice a week statistically benefited from prophylaxis up to 12 months after cure. Although relapse rates at 12 months of those treated prophylactically was 8.3% compared to 31.8% of those who were not prophylactically, there were insignificant differences in relapse rates between study groups at 36 months post-cure. While it is unknown if increasing the frequency of dosing would create a better protection against onychomycosis, it is still unclear whether prophylactic application of antifungal medications help prevent onychomycosis in diabetic patients [20].

Conclusion

Onychomycosis and tinea pedis have been attributed to increasing the risk of diabetic foot ulceration and infections, especially in the elderly male population, individuals having diabetes for a longer duration, and diabetics with neuropathy and/or PVD. Based on this review, preventative measures for foot fungal infections including foot washing hygiene, wearing modified socks, shoe wear sanitation, potentially using prophylactic topical antifungal medication on nails, and stressing the importance of attending routine diabetic foot risk assessment appointments in accordance to the Lavery-Armstrong guidelines should be considered during diabetic foot care education [21].

References

  1. Wild S, Roglic G, Green A, Sicree R, and King H. Global Prevalence of Diabetes: Estimates for the year 2000 and projections for 2030. Diabetes Care. 27: 1047-1053, 2004.
  2. Rice JB, Desai U, Cummings AKG, Birnbaum HG, Skornicki M, and Parsons NB. Burden of Diabetic Foot Ulcers for Medicare and Private Insurers. Diabetes Care. 37: 651-658, 2014.
  3. Pham H, Armstrong DG, Harvey C, Harkless LB, Giurini JM, and Veves A. Screening Techniques to Identify People at High Risk for Diabetic Foot Ulceration. Diabetes Care. 23: 606-611, 2000.
  4. Johannesson A, Larsson GU, Ramstrand N, Turkiewicz A, Wiréhn AB, and Atroshi I. Incidence of Lower-Limb Amputation in the Diabetic and Nondiabetic General Population. Diabetes Care. 32: 275-280, 2009.
  5. Boyko EJ, Ahroni JH, Cohen V, Nelson KM, and Heagerty PJ. Prediction of Diabetic Foot Ulcer Occurrence Using Commonly Available Clinical Information: The Seattle Diabetic Foot Study. Diabetes Care. 29: 1202-1207, 2006
  6. Zhong A, Li G, Wang D, Sun Y, Zou X, and Li B. The risks and external effects of diabetic foot ulcer on diabetic patients: A hospital-based survey in Wuhan area, China. Wound Repair and Regeneration. 25: 858-863, 2017.
  7. Gupta AK, Gupta MA, Summerbell RC, Cooper EA, Konnikov N, Albreski D, et al. The epidemiology of onychomycosis: possible role of smoking and peripheral arterial disease. J Eur Acad Dermatol Venereol. 14: 466–469, 2000.
  8. Gupta AK, Konnikov N, MacDonald P, Rich P, Rodger NW, Edmonds MW, et al. Prevalence and epidemiology of toenail onychomycosis in diabetic subjects: a multicentre survey. Br J Dermatol. 139:665-671, 1998.
  9. Drake LA, Scher RK, Smith EB, Faich GA, Smith SL, Hong JJ, et al. Effect of onychomycosis on quality of life. Journal of the American Academy of Dermatology. 38: 702-704. 1998
  10. Rich P, and Hare A. Onychomycosis in a special patient population: focus on the diabetic. Int J of Dermatol. 38: 17-19, 1999.
  11. Oz Y, Qoraan I, Oz A, and Balta I. Prevalence and epidemiology of tinea pedis and toenail onychomycosis and antifungal susceptibility of the causative agents in patients with type 2 diabetes in Turkey. International Journal of Dermatology. 56: 68-74, 2017. 
  12. Papini M, Cicoletti M, Fabrizi V, and Landucci P. Skin and nail mycoses in patients with diabetic foot. G Ital Dermatol Venereol. 148: 603-608, 2013
  13. Gulcan A, Gulcan E, Oksuz S, Sahin I, Kaya D. Prevalence of Toenail Onychomycosis in Patients with Type 2 Diabetes Mellitus and Evaluation of Risk Factors. JAPMA. 101: 49-54, 2011.
  14. Legge BS, Grady JF, and Lacey AM. The Incidence of Tinea Pedis in Diabetic versus Nondiabetic Patients with Interdigital Macerations. JAPMA. 98: 353-356, 2008.
  15. Takehara K, Amemiya A, Mugita Y, Tsunemi Y, Seko Y, Ohashi Y, et al. The Association between Tinea Pedis and Feet-Washing Behavior in Patients with Diabetes: A Cross-sectional Study. Adv Skin Wound Care. 11: 510-516, 2017.
  16. Broughton RH. Reinfection from socks and shoes in tinea pedis. Br J Dermatol. 67: 249-254, 1995.
  17. Tarbuk A, Grancarić AM, and Magaš S. Modified Cotton Socks- Possibility to Protect from Diabetic Foot Infection. Coll Antropol. 39: 177-183, 2015. 
  18. Ghannoum MA, Isham N, and Long L. Optimization of an infected shoe model for the evaluation of an ultraviolet shoe sanitizer device. JAPMA. 102: 309-313, 2012.
  19. Vlahovic TC. Onychomycosis: Evaluation, Treatment Options, Managing Recurrence, and Patient Outcomes. Clin Podiatr Med Surg. 33: 305-318, 2016.
  20. Sigurgeirsson B, Olafsson JH, Steinsson JT, Kerrouche N, and Sidou F. Efficacy of amorolfine nail lacquer for the prophylaxis of onychomycosis over 3 years. JEADV. 24: 910-915, 2010.
  21. Boulton AJ, Armstrong DG, Albert SF, Frykberg RG, Hellman R, Kirkman MS, et al. Comprehensive Foot Examination and Risk Assessment. Endocrine Practice. 14: 576-583, 2008.

Comparing the etiologies, signs and drug treatments of gout: Literature review

by Ebony Love DPM1, Lesly Robinson DPM1, Tracey Vlahovic DPM1*, Ziad Labbad DPM1, Gilbert K Huang BS2

The Foot and Ankle Online Journal 12 (3): 1

Gout affects millions of patients each year.  This inflammatory arthritis results from elevated body uric acid, which leads to deposition of monosodium urate crystals mainly in joints. Since this condition can be affected by different factors within our lifestyles, modern medications have not been made to specifically target the causative factor. This article reviews recent literature by presenting the common etiologies and discussing drug innovations.

Keywords: gout, hyperuricemia, colchicine

ISSN 1941-6806
doi: 10.3827/faoj.2018.1203.0001

1 – Faculty, Temple University School of Podiatric Medicine
2 – PGY-4 Temple University School of Podiatric Medicine
* – Corresponding author: traceyvlahovicdpm@yahoo.com


Affecting millions, gout has persisted throughout a long span of human civilization when first identified by the Egyptians and recognized by Hippocrates. It was thought to be a “disease of kings” due to its association with luxury foods and alcohol consumption, which were affordable to only the wealthy. Today, we know that gout is a form of inflammatory arthritis resulting from elevated body uric acid pool, which leads to deposition of monosodium urate (MSU) crystals mainly in joints [1]. Since this condition can be affected by different factors within our lifestyles, modern medications have not been made to specifically target the causative factor, which ultimately only suppress the symptoms. This article reviews recent literature by presenting the common etiologies and discussing drug innovations.

Methods

A thorough search of the published literature regarding (i) the epidemiology of gouty arthritis; (ii) signs and lab results presentation; (iii) drug management for gouty arthritis patients; and (iv) new drugs on the rise. The searches were then prioritized on usage based on the date of publication and degree of relevance to the four topics mentioned. 

Results

The epidemiology of gout can be characterized by its prevalence and risk factors such as diet, comorbidities, and heredity. The prevalence of gout among US was 3.9% (8.3 million individuals); 6.1 million men and 2.2 million women [2-4]. In terms of diet for gouty patient, fructose, red meat, and alcohol intake increases serum uric acid levels drastically. Major comorbidities within the population include obesity, renal disease, hypertension, and metabolic syndrome [1]. ATP-binding gene (ABCG2) and sodium-dependent monocarboxylate transporter gene (SLC2A9) showed significant association with development of gout [3]. Although radiologic evidence assists in the diagnosis of gout, the presence of MSU crystals with needle aspiration remains the gold standard [5-6]. Standard drug management of choice remains an NSAID (indomethacin) and colchicine for acute gout; regimen for chronic patient varies [7-9]. Research continues for the latest FDA approved drug Lesinurad as well as producing IL-1 inhibiting biological therapies [10].

Discussion

In terms of prevalence of gout among US, all relevant paper referenced the study data from NHANES 2007-2008 which estimated 6.1 million men and 2.2 million women have gout. Furthermore, the survey was compared to a previous data over the past two decades and presented an overall 1.2% increase prevalence of gout and 3.2% on hyperuricemia. Since the increase of hyperuricemia was greater, it is indicated that many people in the US are on the borderline of developing gouty arthritis. Possible overuse of diuretics and aspirin as well as comorbidities such as obesity and hypertension could attribute to that increase as well. 

In most studies, hyperuricemia is classified when serum urate level is greater than 7.0 mg/dL. When purine-rich diet foods were compared, red meat and seafood produced significantly more purine and led to increased risk of gout incident as opposed to purine-rich vegetables and low-fat dairy products. Fructose degrades purine nucleotides and acts as a substrate for uric acid production, which increases the risk of gouty attacks. Consumption of sugar-sweetened soft drinks of two or more servings per day increases the risk of gout incident by an average of 106%. Alcohol consumption, particularly beer, is predispose to gout due to production of purine metabolic substrate guanosine, which enhances nucleotide turnover and impair renal urate excretion via lactic acidosis. Although moderate consumption of alcohol (2-6 oz/wk) did not affect increase gouty incident, those who drink two or more drinks per day had 2.5 times the risk. 

Figure 1 Average percentage of comorbidities with gout.

On the other hand, coffee and vitamin C were examined and found to decrease gouty incidence due to their antioxidant properties that increase insulin sensitivity and enhance renal urate excretion. Additionally, caffeine is a methylxanthine that competitively inhibits xanthine oxidase, which is the major enzyme in purine metabolic pathway.

Since gout is created through the body’s inability to decrease serum urate level, systemic comorbidities can potentially worsen and exacerbate the attack. Through 13 studies comparing comorbidities with gout, hypertension, dyslipidemia, cardiovascular disease, diabetes mellitus, and renal disease are all highly prevalent in individuals with gout. Hypertension was present in 40-74% of individuals with gout, dyslipidemia in 15-59%, cardiovascular disease in 13-41%, diabetes mellitus in 6-32%, and renal disease in 13-44% (Figure 1). 

ATP-binding cassette subfamily G member 2 (ABCG2) gene produces the transporter that causes the export of uric acid out of the proximal tubules which overall decreases the intracellular urate concentration. With mutation of this gene, serum uric acid levels remain high and contribute to roughly 10% of individuals with gout. The gene SLC2A9, encodes a glucose/fructose transporter in the kidneys, which when coupled with the principal renal urate reabsorption transporter, will cause the excretion of urate from the tubule cells. Once again, a mutation within this specific gene will cause a decrease count of transporter produced to reduce urate levels in the serum. 

Colchicine is a lipophilic alkaloid with short half-life but long actual half-life in plasma and metabolized by cytochrome P450. The anti-inflammatory effects can disrupt microtubule function in activated neutrophils and prevent crystal-induced inflammation, which is why it’s indicated as the initial drug of choice for gouty attacks. Colchicine can also be used as prophylaxis for gout patients (0.6 mg bid) for 90 days and indomethacin (50 mg tid) for 10 days. After administering colchicine to reduce acute inflammatory attacks, appropriate steps can be taken to determine if the patient is under-secreting or overproducing uric acid. Further medication can then be prescribed for each specific case:

  • Indomethacin (NSAID) –analgesic, antipyretic, and anti-inflammatory by decreasing prostaglandin synthesis (50mg PO q8)
  • Colchicine (Colcrys) – modulates anti-inflammatory pathways for gout, prevents microtubule assembly, and disrupts inflammasome activation (0.6-1.2mg PO initially, 0.6mg PO q1 until GI symptoms or pain relief; 0.6mg PO once daily or q12 as prophylaxis)
  • Allopurinol (Zyloprim) – blocks uric acid production by inhibiting xanthine oxidase (100-600mg PO daily)
  • Febuxostat (Uloric) – non-purine xanthine oxidase inhibitor (40-80mg PO daily)
  • Probenecid (Benemid) – decrease uric acid reabsorption (250mg PO bid for 1 week, then 500mg PO bid)

Lesinurad (Zurampic) is the most recent FDA approved medication. It is the first selective uric acid resorption inhibitor and inhibits urate transporter-1 (URAT1), which promotes uric acid excretion. Additionally, lesinurad is indicated for hyperuricemia with gout patients that have not achieved target serum urate levels. This requires the drug to be co-administered with a xanthine oxidase inhibitor. Interleukin-1 is a pro-inflammatory cytokine that can mediate and initiate inflammation within the body. By creating inhibitors that specifically target the cytokine and inflammasome, gouty inflammations can be reduced. 

Conclusion

Although the criteria for diagnosing and managing gout are beginning to solidify in modern standard of care settings, the results of this literature review demonstrate a need of long-term research with advancing technologies on new medications to understand their specific effects on the suppression of recurrent gouty episodes.

References

  1. Schlesinger N. Difficult-to-treat gouty arthritis: a disease warranting better management. Drugs. 2011;71(11):1413-39.
  2. Zhu Y, Pandya BJ, Choi HK. Prevalence of gout and hyperuricemia in the US general population: the National Health and Nutrition Examination Survey 2007-2008. Arthritis Rheum. 2011;63(10):3136-41.
  3. Newcombe D. S. (2013). Gout Basic Science and Clinical Practice. London: Springer International Publishing AG.
  4. Roddy E, Choi H. (2014). Epidemiology of Gout. Elsevier Inc. 
  5. Schlesinger N. Diagnosis of gout: clinical, laboratory, and radiologic findings. Am J Manag Care. 2005;11(15 Suppl):S443-50.
  6. Watt I, Middlemiss H. (1975). The radiology of gout. Elsevier Inc.
  7. Shekelle P. G, FitzGerald J, Motala A, et al. (2016). Management of Gout. Agency for Healthcare Research and Quality.
  8. Perez-Ruiz F., Herrero-Beites A. M. (2014). Managing Gout in Primary Care. Springer International Publishing AG.
  9. Burns CM, Wortmann RL. Latest evidence on gout management: what the clinician needs to know. Ther Adv Chronic Dis. 2012;3(6):271-86.
  10. Keenan RT, Schlesinger N. New and Pipeline Drugs for Gout. Curr Rheumatol Rep. 2016;18(6):32.
  11. Neogi T, Jansen TL, Dalbeth N, et al. 2015 Gout Classification Criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheumatol. 2015;67(10):2557-68.
  12. Newcombe D. S. (2013). Diagnostic Procedures in the Management of Gout. London: Springer.
  13. Burns CM, Wortmann RL. Gout therapeutics: new drugs for an old disease. Lancet. 2011;377(9760):165-77.

Graft take rates in low-risk and high-risk patients with negative pressure wound therapy vs tie-over dressings

by Brent H Bernstein DPM1, Yvonne Cha DPM1*, Justin Guiliana DPM1

The Foot and Ankle Online Journal 12 (2): 6

Establishing a reliable method of securing skin grafts over wounds of the lower extremities remains a challenge, particularly in high-risk patients. Studies have reported on the use of negative pressure wound therapy using reticulated open-cell foam (NPWT/ROCF) as delivered by V.A.C.® Therapy (KCI Licensing, Inc., San Antonio, TX) as a bolster dressing over split- thickness skin grafts in various populations. The aim of this study was to compare take rates of lower extremity grafts in high-risk patients who received NPWT/ROCF versus tie-over dressings. We also retrospectively evaluated graft take rates in low-risk (no comorbidities) versus high-risk (≥1 comorbidity) graft patients who received post-graft NPWT/ROCF versus tie-over dressings. Forty-seven STSG patient records were analyzed. In the high-risk patient group, a significantly higher number of patients obtained ≥80% graft take rate in the NPWT/ROCF versus tie-over group (p=0.008). Graft take rates were similar between the two dressings in low-risk patients. In this study, NPWT/ROCF appears to improve STSG take compared to tie-over dressings in high-risk patients, which may be related to an improved contact zone between the graft and wound site.

Key words: negative pressure wound therapy, V.A.C. therapy, split-thickness skin graft

ISSN 1941-6806
doi: 10.3827/faoj.2018.1202.0006

1 – St. Luke’s University Health Network- Allentown, Pennsylvania
* – Corresponding author: yvonne0cha@gmail.com


Closure of lower extremity wounds remains a challenge in patients with considerable comorbidities. An ever-increasing number of closure options have prompted us to adopt a “reconstructive elevator” approach to our modern lower extremity practice (Figure 1). Typically in our practice, anatomic location, biomechanics and bony pressure points dictate plastic closure selection. Wounds with bone, joint, or tendon exposure without periosteum or paratenon larger than 0.5 cm in diameter are treated with flaps. Wounds located on the weight-bearing areas of the foot are typically treated with secondary intention or preferably cultured cellular grafts. In the literature, a split-thickness skin graft (STSG) is considered by some surgeons to be the preferred method of repair for moderate to large soft tissue defects on non-weight-bearing areas of the extremities [1-5].

Split-thickness skin grafting is a method of transposition of human skin (epidermal and a portion of the dermal layers) from a harvest to recipient site. The stages of STSG healing are: plasmatic imbibition, inosculation, and capillary ingrowth. A skin graft survives the first 48 hours through imbibition, or diffusion, of exudate through the host bed that supplies nutrients and removes waste products. The next step is inosculation, in which the graft develops connections with the recipient blood vessels. 

Figure 1 The “reconstructive elevator” approach to modern lower extremity practice.

Finally, capillary in-growth occurs when new vessels grow into the graft from the host bed and actively innervate the graft to establish blood supply [6, 7]. 

Patient comorbidities, such as diabetes mellitus (DM), lymphedema, and peripheral vascular disease (PVD) are known to impede wound healing [8], and can lead to graft failure. Other reasons for graft failure include ischemia, seroma/hematoma formation, fluid collection, shearing forces, infection, desiccation, and rejection. Reported skin graft failure rates vary dramatically, depending on wound etiology and a host of other factors. The method used to secure the graft can be a critical element in reducing opportunities for failure. Goals of a bolster dressing are to provide even pressure, immobilization and restriction of shearing to the graft, as well as prevent seroma or hematoma formation while providing a moist wound bed beneath the STSG [7]. 

During the past several years, adjunctive use of negative pressure wound therapy using reticulated open-cell foam (NPWT/ROCF) as delivered by V.A.C.® Therapy (KCI Licensing, Inc., San Antonio, TX) has become a well-established method of securing the graft to the recipient bed. NPWT/ROCF can act as both a temporizing bridge to STSG closure as well as the dressing over the STSG [4, 5, 8-12]. Obtaining successful graft take requires that the skin graft remain immobilized for 2-5 days or until revascularization occurs [13]. The compressed NPWT/ROCF foam maintains continuous, firm contact between the graft and wound bed while the negative pressure actively removes exudates and infectious material from the wound bed. Foam pliability allows relative movement of the wound surface without compromising pressure [4]. 

While many studies have reported on the use of NPWT/ROCF over STSGs, its relative efficacy versus traditional tie-over bolster dressings has been debated in the literature. We hypothesized that the use of NPWT/ROCF creates an improved contact zone between the graft and wound site as compared to tie-over dressings, which may result in higher graft take rates. We further hypothesized that among high-risk patients with known comorbidities, application of NPWT/ROCF over STSGs on lower extremity wounds leads to higher graft take rates compared to tie-over dressings. To test these hypotheses, we performed a retrospective cohort analysis examining skin graft take rates of high-risk patients treated with NPWT/ROCF versus tie-over cotton bolster dressings. 

Patients and Methods

We retrospectively reviewed the charts of consecutive patients who received an STSG procedure performed by the leading author as primary surgeon between March 1994 and May 2007. Records were divided into four groups: 1) High-risk NPWT/ROCF, 2) High-risk tie-over bolster, 3) Low-risk NPWT/ROCF and 4) Low-risk tie-over bolster. Patients were considered high-risk if they had any of the following comorbidities: DM, end-stage renal disease (ESRD), contralateral lower-extremity amputation, lymphedema, smoking, peripheral nerve disorders, spinal cord injuries (SCI) or disorders, PVD, venous insufficiency, immunocompromised, or connective tissue disorders. A hospital IRB Waiver of Authorization was obtained to perform this retrospective data analysis, based on its minimal risk level to patients. All tie-over bolster and NPWT/ROCF dressings were similarly fashioned and placed by the same surgeon. Tie-over patients were treated with a post-graft bolster dressing consisting of normal saline soaked absorbent cotton balls and tied over the graft using 3-0 monofilament nylon sutures. 

Figure 2 NPWT application diagram.

STSGs in the NPWT/ROCF-treated groups were covered with an available (eg, ADAPTIC®) porous non-adherent layer, an NPWT/ROCF dressing and semi-permeable drape with tubing. The tubing was connected to the subatmospheric pressure unit with -125mmHg applied for 3-5 days (Figure 2). The authors’ medical records, digital photograph archives, and surgical logs were reviewed, and percentage of graft take at 14 days post-operative was recorded for each patient. Total number patients with ≥80% and ≥50% graft take were compared between both treatment arms for both high- and low-risk groups. Fisher’s exact two-tailed test was utilized to compare the groups by percentage of graft take.

Results

Forty-seven patients met the study inclusion criteria. 15 patients in the NPWT/ROCF group and 21 in the tie-over group were classified as high-risk. There were 5 patients in the NPWT/ROCF group and 6 patients in the tie-over group that were classified as low-risk. 

Frequencies of patient comorbidities are listed in Table 1. Wound etiologies in the low-risk patient group included traumatic wounds, post-debridement wounds from necrotizing fasciitis or bites, post-lesion excision sites, and decubitus ulcers. 

Table 1 Graft rate take rate.

There was a significant difference between the two treatment arms of high-risk patients that achieved a graft take rate ≥80%: 13 of 15 for the NPWT/ROCF group versus 9 of 21 for the tie-over group (p=0.008) (Table 1). The number of patients in the high-risk cohort that achieved ≥50% graft take was also significantly lower in the tie over patient group (14/21) versus the NPWT/ROCF group (15/15; p=0.027). Complete graft failure (0% graft take) was reported in the remaining 7 tie-over and 1 NPWT/ROCF high-risk patients. The average percent graft take rates for high-risk patients in the NPWT/ROCF versus tie-over groups were 90.3% vs. 55.2%, respectively. When subgrouped by comorbidities, the average graft take rate in the NPWT/ROCF-treated patients was higher than the tie-over patients in each of the subgroups, but the difference was not significant, owing to low populations in all subcategories (Table 1). All low-risk NPWT/ROCF and tie-over patients achieved a graft take rate of 80% or greater (Table 2). 

Discussion

The retrospective analysis demonstrated significantly improved STSG take rates and survival in high-risk patients who received NPWT/ROCF, compared to traditional tie-over dressings. Our graft take rates in both the high- and low-risk NPWT/ROCF groups—90.3% and 100%, respectively—mirror that which is reported in the literature [14-16]. In 1997, Argenta and Morykwas first demonstrated effective use of NPWT/ROCF as a bolster for STSGs on a variety of acute and chronic wounds [14]. Blackburn et al [15] showed a ≥95% STSG take rate with the use of NPWT/ROCF on contoured wounds in complex anatomic regions. 

Comorbidity High risk tie-over group  High risk NPWT/ROCF Group 
n Average % take 80% graft take (n) ≥50% graft take (n) n Average % take  ≥80% graft take (n) ≥50% graft take (n)
DM, ESRD, contralateral lower extremity amputation, PVD 14 57.9 6 4 13 93.1 12 1
SCI/peripheral neuropathy/congenital spinal cord lesion 0 n/a n/a n/a 0 n/a n/a n/a
Venous insufficiency 6 58.3 3 2 1 95 1 0
Connective tissue disorder/immunocompromised 0 n/a n/a n/a 1 50 0 0
smoker 1 0 0 1 0 n/a n/a n/a
total 21 55.2 9 7 15 90.3 13 1

Table 2 Comorbidity and graft rate take rate.

A consecutive case series of 61 STSG patients revealed a significant decrease in repeated STSGs for the NPWT/ROCF group as compared to the bolster dressing group, suggesting improved graft survival with adjunctive use of NPWT/ROCF [19]. Our patients have experienced other advantages of NPWT/ROCF reported in the literature, such as enhanced patient mobility, shorter hospital stay, and an earlier return to daily activities while the dressing is in place [2, 15, 17]. 

Our study’s similar graft take rates between the two treatment arms of the low-risk population somewhat support outcomes of other clinical studies that have reported no significant difference in STSG take rates between NPWT/ROCF and tie-over dressing groups [3, 18-19]. Moisidis et al [18] performed a prospective, blinded, randomized controlled trial comparing NPWT/ROCF to standard bolster dressings on 22 adult inpatients with wounds requiring skin grafting. There were no differences in quantitative graft take between the two groups, but NPWT/ROCF had a significantly better qualitative graft take as compared to the standard bolster dressing [18]. In a retrospective chart review, Stone et al also found similar graft take rates between NPWT/ROCF and bolster dressings in 40 trauma patients who underwent soft tissue loss and fasciotomies [3]. Our study results appear to suggest prudent use of NPWT/ROCF in low-risk patients, although the small sample sizes clearly warrant further study. 

This study has several limitations including its small size, retrospective nature, and lack of randomization and blinding. Unobserved covariates which could also account for differences in graft take, such as wound size, duration, or type of wound treatment prior to grafting, may also distort the conclusions of the study. Also, the author believes that as his practice changed from utilizing the tie-over dressing to the use of NPWT/ROCF over time, perhaps an improvement in surgical technique could have occurred as well over this period of time. This improvement in technique could have allowed an improved success in the latter portion of the cohort when NPWT/ROCF was utilized more often. 

To the authors’ knowledge, this study is the first to delineate between high- and low-risk patient populations in comparing NPWT/ROCF versus tie-over bolster treatment over STSGs. Our results suggest that the presence of patient comorbidities may be an important consideration when choosing a bolster dressing. Combining high and low-risk populations within cohorts may underestimate the utility of NPWT/ROCF in high-risk populations. Our preliminary results are promising and suggest that NPWT/ROCF may be a more efficacious dressing versus traditional tie-over dressings in high-risk patients whereby reliably uniform contact between the graft and dressing is critical to successful graft take.

References

  1. Llanos S, Danilla S, Barraza C, Hernandez I, Nava E, Diaz J. Effectiveness of negative pressure closure in the integration of split thickness skin grafts: a randomized, double-masked, controlled trial. Ann Surg 244(5):700-705, 2006. 
  2. Chang KP, Tsai CC, Lin TM, Lai CS, Lin SD. An alternative dressing for skin graft immobilization: negative pressure dressing. Burns 27(8):839-42, 2001. 
  3. Stone P, Prigozen J, Hofeldt M, Hass S, DeLuca J, Flaherty S. Bolster versus negative pressure wound therapy for securing split-thickness skin grafts in trauma patients. Wounds 16(7):219-223, 2004. 
  4. Schneider AM, Morykwas MJ, Argenta LC. A new and reliable method of securing skin grafts to the difficult recipient bed. Plast Reconstr Surg 102(4):1195-1198, 1998. 
  5. Repta R, Ford R, Hoberman L, Rechner B. The use of negative-pressure therapy and skin grafting in the treatment of soft-tissue defects over the Achilles tendon. Ann Plast Surg 55(4):367-70, 2005. 
  6. Warriner RA. Wound assessment. In Wound Care Practice, pp75-100, edited by PJ Sheffield, APS Smith, CE Fife. Best Publishing Company, Flagstaff, 2004. 
  7. Gupta S, Gabriel A, Shores J. The perioperative use of negative pressure wound therapy in skin grafting. Ostomy Wound Manage 50(4A Suppl):32-34, 2004. 
  8. Armstrong DG, Lavery LA, Diabetic Foot Study Consortium. Negative pressure wound therapy after partial diabetic foot amputation: a multicentre, randomised controlled trial. Lancet 366(9498):1704-1710, 2005. 
  9. Eginton MT, Brown KR, Seabrook GR, Towne JB, Cambria RA. A prospective randomized evaluation of negative-pressure wound dressings for diabetic foot wounds. Ann Vasc Surg 17(6):645-649, 2003. 
  10. Morris GS, Brueilly KE, Hanzelka H. Negative pressure wound therapy achieved by vacuum-assisted closure: Evaluating the assumptions. Ostomy Wound Manage 53(1):52-57, 2007. 
  11. Carson SN, Overall K, Lee-Jahshan S, Travis E. Vacuum-assisted closure used for healing chronic wounds and skin grafts in the lower extremities. Ostomy Wound Manage 50(3):52-58, 2004. 
  12. Isago T, Nozaki M, Kikuchi Y, Honda T, Nakazawa H. Skin graft fixation with negative-pressure dressings. J Dermatol 30(9):673-678, 2003. 
  13. Rudolph R, Ballantyne DL, Jr. Skin Grafts. In Plastic Surgery, pp 221-274, edited by JG McCarthy, Saunders, Philadelphia, 1990. 
  14. Argenta LC, Morykwas MJ. Vacuum-assisted closure: a new method for wound control and treatment: clinical experience. Ann Plast Surg 38(6):563-576, 1997. 
  15. Blackburn JH, Boemi L, Hall WW et al. Negative pressure dressings as a bolster for skin grafts. Ann Plast Surg 40(5):453-457, 1998. 
  16. Molnar JA, DeFranzo AJ, Marks MW. Single-stage approach to skin grafting the exposed skull. Plast Reconstr Surg 105(1):174-177, 2000. 
  17. Sposato G, Molea G, Di CG, Scioli M, La R, I, Ziccardi P. Ambulant vacuum- assisted closure of skin-graft dressing in the lower limbs using a portable mini- VAC device. Br J Plast Surg 54(3):235-237, 2001. 
  18. Moisidis E, Heath T, Boorer C, Ho K, Deva AK. A prospective, blinded, randomized, controlled clinical trial of topical negative pressure use in skin grafting. Plast Reconstr Surg 114(4):917-922, 2004. 
  19. Scherer LA, Shiver S, Chang M, Meredith JW, Owings JT. The vacuum assisted closure device: A method of securing skin grafts and improving graft survival. Arch Surg 137(8):930-934, 2002.

Surgical excision of Morton’s neuroma: Does it provide a reliable outcome?

by Muhammad Murtaza Khan1*, and Dakshinamurthy Sunderamoorthy2

The Foot and Ankle Online Journal 12 (2): 5

This study involves a retrospective analysis of the surgical intervention for treatment of Morton’s neuroma of the foot for patients that were treated over three years period. The aim of this study is to evaluate the long-term outcome following operative removal of the Morton’s neuroma of foot using MOXFQ. We retrospectively evaluated the outcome of 13 patients (14 feet) who were operated from February 2015 to March 2018 for excision of Morton’s neuroma using a dorsal approach. We evaluated the outcome was using clinical follow up notes, examination findings and the Manchester Oxford Foot Questionnaire score. Thirteen patients (14 feet) were operated during this period, out of which 12 were females and one male with a mean age of 58 years. One patient had bilateral symptomatic disease. 11 out of 13 patients (84.6 %) were satisfied with their results of surgery after a mean follow-up period of 34.42 ± 9.81 months. Biopsy supported the clinical diagnosis in 13/14 case (92.857%). Preoperative diagnosis was confirmed by radiologist as Morton’s neuroma on 12/14 cases (85.71%). The predominant modality of choice was ultrasound of feet, however, MRI of the foot was advised in one case only. Statistically significant difference was appreciated between preoperative and postoperative MOXFQ score (41.92 ± 10.47 verses 8± 15.11), respectively, with a p value < 0.0001 CI 95% SI 4.913. Our study shows surgical excision of Morton’s neuroma is a reliable procedure and it gives a good outcome and it is maintained over a period of 3 years.

Keywords: Morton’s neuroma, MOXFQ, dorsal approach

ISSN 1941-6806
doi: 10.3827/faoj.2018.1202.0005

1 – 6 Saxby House Church lane Scunthorpe (DN15 7HY)
2 – Northern Lincolnshire and Goole Foundation NHS Trust (DN15 7BH)
* – Corresponding author: Murtazakhan142@yahoo.com


Morton’s neuroma is non-malignant enlargement of the common plantar digital nerve, usually seen at the 2nd or 3rd intermetatarsal spaces [1,2]. It is one of the most common causes of metatarsalgia and majority of clinicians consider the clinical diagnosis as an indication to treatment [3]. Morton’s neuroma should be considered as part of differential diagnosis in any patient complaining of forefoot pain [5]. The most common presenting complaint is burning pain on the plantar aspect of the foot between the metatarsal heads of corresponding toes [3]. Others complain of walking on a lump on the ball of the great toe, shooting pain and tingling in the involved digits [5]. Pain is particularly aggravated by walking and wearing tight shoes and is relieved by rest [3]. Researchers were not able to identify the definitive cause of this condition. Some consider it due to hypermobility of 4th ray over the cuboid as part of the etiology, explaining why the third metatarsal space is commonly associated with the disease [3].

It may also be due to entrapment of nerve at the distal metatarsal ligament or may be due to trauma, equinus deformity or autonomic neuropathy [5]. Considering the variable presentation of patient symptoms, the modality of choice and surgical approach is also subjected to active debate over the years. Surgery is considered the treatment of choice with either dorsal or plantar approach. However, few consider equal efficacy of either dorsal or plantar approach for excision [7]. Others considered dorsal approach only in cases of recurrent disease [8].

Some advocate conservative treatment as part of regimen. However, it is associated with variable success rate and many patients ultimately underwent surgery after initial period of successful non-surgical management. Moreover, the role of corticosteroids with local anesthetic is also considered futile in long term follow-up [1] (6 months). 

The use of histology was considered as an essential part of postoperative work-up for consideration of the diagnosis, however, others considered it as an economic burden unless it is a recurrent disease or ambiguity regarding diagnosis during surgery [5].

Materials and Methods 

We retrospectively evaluated our thirteen cases (fourteen feet) from 2015 to 2018 and the postoperative outcome was evaluated using Manchester Oxford Foot and Ankle Questionnaire. All patients with neuroma were considered for the study. Any patient with recurrent disease, diagnosed case of other foot pathology like rheumatoid arthritis, associated injuries in the metatarsophalangeal joint, any patient operated for recurrent disease or not willing to answer the questionnaire over the phone were excluded from the study. In order to avoid any bias during study we evaluated the patient outcome following surgery not only through clinical notes, radiology reports (USG/ MRI) histopathology but also used operative summaries. Moreover, additional information was extracted by ringing the patients using their documented contact numbers and after taking verbal consent we asked question as in MOXFQ, thus cross checking the information provided in the post-operative follow up pathway in terms of patient satisfaction/ dissatisfaction status. 

Figure 1 Patient demographics.

Figure 2 Management characteristics.

The results were evaluated by calculating the mean, standard deviation, standard error for values obtained. For evaluation whether the pre and post-operative MOXFQ score is statistically significant we calculated the p value using the mean values of pre and post-operative MOXFQ score.  P value <0.05 was considered as significant.  

Results

Thirteen patients (14 feet) were operated during this period, out of which 12 were females and one male with a mean age of 58 years (Figure 1). Fifty percent (7/14) were operated in 2014. Thirty six percent (5/14) in 2016. Seven percent in both 2017 & 2018 (1/14) in each year.  One patient had bilateral symptomatic disease. Eight out of 14 cases (57%) have disease confined to third metatarsal space and 6/14 cases (43%) have disease in second metatarsal space. Eleven out of 13 patients (84.6 %) were satisfied with their results of surgery after a mean follow up period of 34.42 ± 9.81 months. 

Biopsy supported the clinical diagnosis in 13/14 cases (92.85%). Preoperative diagnosis was confirmed by radiologist as Morton’s neuroma on 12/14 cases (85.71%). The predominant modality of choice was ultrasound of feet (Figure 3). 

Figure 3 Method of diagnosis.

Figure 4 Pre- and postoperative MOXFQ scores.

However, MRI foot was advised in one case only. Conservative treatment was opted by 5/14 patients (35%). Out of these one was offered injection of local anesthetic with corticosteroid in clinic and 4/14 (28.5%) were given ultrasound guided injection of local anesthetic with steroid. However, the mean relief period was 1.22± 2.2 months for all 5 patients and they ultimately opted for surgery (Figure 2). Statistically significant difference was appreciated between pre-operative and post-operative MOXFQ score (41.92 ± 10.47 Verses 8± 15.11) respectively with p value < 0.0001 CI 95% SI 4.913 (Figure 4).

Discussion

Our results showed a patient satisfaction rate of 84.6%, which is higher than the documented success rate of surgery. It is variably reported in literature however, it never exceeds 80% [1]. Some researchers have raised concerns regarding the use of dorsal approach for surgery compared to the plantar approach, but our results do not support this argument. In fact, we were able to treat our patient with satisfactory results using a dorsal approach.

The literature supports the use of dorsal approach as it provides good exposure, less healing problems and good exposure of deep metatarsal transverse ligament. Moreover, there was a significant delay in full-weight bearing for the plantar incision and increased risk of wound healing problems [3]. Another study demonstrating the efficacy of plantar approach claiming a complication rate of 4 to 36% for plantar approach compared to 2 to 34% for dorsal approach [6]. Another group of researchers claim that equal satisfactory results can be obtained from either a plantar or dorsal approach and choice should be left for surgeon experience and personal preference [7]. Similarly, some surgeons prefer using a planter approach for recurrent disease, as surgery can be complicated by scar tissue if the neuroma is approached through the site of a previous incision [8].

In our case series, the predominant affected population were females with a mean age of 58 years. Again, this finding matches with already established research, as women in the middle ages are prone to disease with an average age of 50 years and female-to-male ratio of 4:1[3].

However, the literature supports the disease predominance in the third metatarsal space; in our study, although 57% of patients had the disease in the said space but 43% patient demonstrated Morton’s neuroma in 2nd intermetatarsal space. As per existing evidence, the presence of disease in 3rd intermetatarsal and second metatarsal space is 66% and 21% respectively [3]. In one study, however, they were able to report equal incidence of disease in 2nd and 3rd intermetatarsal space [5].

In this series, we offered conservative treatment in every case before moving towards surgery. Five out of 14 patients accepted the offer and went for ultrasound guided injection and one opted the option of blind injection in the foot by clinician. Although, some support the use of ultrasound guided injection, other prefer identification of pain spot in the clinic and infiltration of local anesthetic and steroid at the most tender point claiming favorable/comparable results with blind injection [1].  

In our case series, the results of conservative management using local anesthetic and steroid were disappointing with a mean relief of just 1.22 ± months and all patients ultimately opted to go for surgery.

This finding is very much coherent with existing evidence as all patients managed conservatively for Morton’s neuroma ultimately opted for surgery as long-term results are usually disappointing [2]. Based on our experience, we don’t recommend the use of steroid and local anesthetic as a definitive treatment of choice for Morton’s neuroma unless the patient is deemed unfit for surgery. Despite the evolution of less invasive modalities and development in radiological techniques, most of the existing literature still favors surgery as a definitive treatment of this disease [4].

Our set of patients diagnosis is supported by tissue diagnosis of neuroma in 13/14 (92%) cases thus consolidating our clinical assessment. This is much higher than the reported value in one study involving the prospective analysis of Morton’s neuroma disease of the foot where they were able to prove the histological diagnosis in only 78% of operated patients [2]. Moreover, the exceptional results in terms of resolution of symptoms also points toward correct treatment regimen.

Regarding tissue diagnosis, it has been considered as a burden to the health system by some researchers. The reason extracted from the literature narrated the fact that unless there is doubt during surgery it should not be subjected to tissue diagnosis [9]. However, others always give weightage to radiological and histological diagnosis. Few consider the clinical examination as the gold standard for diagnosis [4]. However, others have questioned this technique in modern era of evidence-based medicine [3].

We recommend the support of histology, even if the clinician is sure of diagnosis. Not only does it save any future discomfort in terms of medicolegal issues, but it also excludes an important cause of forefoot pain for future treatment in case the results of surgery are disappointing. Additionally, patients can be counselled regarding the management and guarded prognosis in case of recurrent disease [2].

The modality of choice in our series was ultrasound of foot. Although MRI was requested by clinician in one case only, but it did not add any extra information or change in treatment plan for the patient. Researchers recommend use of both modalities, however, the diagnosis of asymptomatic neuroma is high, especially with ultrasound and it is reported as 54% in some literature. Thus, clinical findings should be correlated with radiological evidence [2]. MRI has sensitivity and specificity of 93% and 68% respectively compared to ultrasound which has sensitivity and specificity of 90% and 88% respectively [3].

In our opinion, long term follow-up is vital for this disease, as in our experience initially satisfied patients may complain of return of symptoms after a mean interval of three months with complaint of pain of similar nature that was experienced before the surgery. 

In our experience, we would recommend reconsidering the diagnosis if it is not proven by radiological work up as it may be one of the factors that can lead to poor outcome after surgery. Although evidence regarding this recommendation is weak in existing literature [2]. Surgical excision of Morton’s neuroma can give excellent outcome after surgery provided patients are chosen wisely.

References

  1. Lizano-díez X, Ginés-cespedosa A, Alentorn-geli E, et al. Corticosteroid Injection for the Treatment of Morton’s Neuroma: A Prospective, Double-Blinded, Randomized, Placebo-Controlled Trial. Foot Ankle Int. 2017;38(9):944-951.
  2. Bucknall V, Rutherford D, Macdonald D, Shalaby H, Mckinley J, Breusch SJ. Outcomes following excision of Morton’s interdigital neuroma: a prospective study. Bone Joint J. 2016;98-B(10):1376-1381.
  3. Di caprio F, Meringolo R, Shehab eddine M, Ponziani L. Morton’s interdigital neuroma of the foot: A literature review. Foot Ankle Surg. 2018;24(2):92-98.
  4. Reichert P, Zimmer K, Witkowski J, Wnukiewicz W, Kuliński S, Gosk J. Long-Term Results of Neurectomy Through a Dorsal Approach in the Treatment of Morton’s Neuroma. Adv Clin Exp Med. 2016;25(2):295-302.: .
  5. Adams WR. Morton’s neuroma. Clin Podiatr Med Surg. 2010;27(4):535-45.
  6. Nery C, Raduan F, Del buono A, Asaumi ID, Maffulli N. Plantar Approach for a Morton’s Neuroma: Surgical Technique. JBJS Essent Surg Tech. 2012;2(3):e14.
  7. Habashy A, Sumarriva G, Treuting RJ. Neurectomy Outcomes in Patients With Morton’s Neuroma: Comparison of Plantar vs Dorsal Approaches. Ochsner J. 2016;16(4):471-474.
  8. Richardson DR, Dean EM. The recurrent Morton’s neuroma: what now?. Foot Ankle Clin. 2014;19(3):437-49.
  9. Mallina RK, Al-dadah K, Patel K, Ramesh P. Is Histopathological Analysis of Interdigital Morton’s Neuroma Necessary?. Foot Ankle Spec. 2017;10(6):520-523.