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Divergent Lisfranc injury with dislocation of great toe interphalangeal joint: A rare case report

by Dr. Ganesh Singh Dharmshaktu1*, Dr. Binit Singh2

The Foot and Ankle Online Journal 10 (3): 3

Injury to the Lisfranc joint is an uncommon event and requires keen evaluation to diagnose it early for the optimal outcome following adequate treatment. Many classifications describe the divergent pattern of this injury as separate entity and even rarer in incidence. The associated ipsilateral great toe interphalangeal dislocation along with the rare divergent pattern of Lisfranc fracture dislocation makes our case unusual. The case was managed by reduction of the great toe interphalangeal dislocation with percutaneous reduction and fixation of Lisfranc injury with screws and multiple K-wires, resulting in a good clinical outcome on follow up.  No single case similar to ours is reported previously to the best knowledge of the authors.

Keywords: foot, injury, dislocation, Lisfranc joint, tarsometatarsal joint, interphalangeal, management, fixation

ISSN 1941-6806
doi: 10.3827/faoj.2017.1003.0006

1 – Assistant Professor, Department of Orthopaedics, Government Medical College, Haldwani , Uttarakhand. India.
2 – Assistant Professor, Department of Orthopaedics, Government Medical College, Haldwani , Uttarakhand. India.
* – Corresponding author: drganeshortho@gmail.com


IInjury to the Lisfranc joint (Tarsometatarsal joint) is a rare event with reported incidence of 0.1 to 0.4% of fracture cases [1]. Early identification and meticulous management, often surgical, is required for optimal outcome as the conservative approach has been linked to poor results [2]. Quenu and Kuss did instrumental work to highlight the anatomical and clinical understanding of Lisfranc joint along with description of the “Lisfranc ligament bundle” bridging second metatarsal and first cuneiform bone as key stabilizing structure of tarsometatarsal (TMT) joint [3]. The classification given by the same authors is widely used and it describes three types of the injury; homolateral, isolated and divergent. Divergent dislocation was described as a complete disruption of the TMT joint with first ray and lesser rays displaced in the opposite direction. Another classification by Hardcastle et al modified the abovementioned classification on the basis of radiological evaluation into three types – complete, partial and divergent [4]. Type C or divergent variant was noted with medialisation of first metatarsal and lateral translation of variable number of rest of the metatarsals. The literature is scant about this rare pattern of injury as compared to other types.

Case Report

A 28-year-old male patient was brought to us with a history of injury to his right foot a few hours earlier. There was swelling and pain after the patient sustained an injury to the foot by the jumping off a moving bus. He reported he lost his balance and his foot was twisted before he fell to hard ground. The exact position of the foot at the time of impact is not properly recalled by the patient. There was visible deformity over medial aspect of foot and great toe suggesting presence of underlying significant bony or soft tissue injury. The radiograph of the affected foot showed fracture dislocation of Lisfranc joint along with inter-phalangeal dislocation of ipsilateral first toe. The pattern of Lisfranc injury was divergent with medial dislocation of first TMT joint and lateral dislocation of the rest of the TMT joint (Figure 1). There was also a fracture of the fifth metatarsal base with minimal displacement. Following informed consent, the patient was planned for urgent reduction of aforementioned injury with internal fixation. The rarity of the injury pattern was explained to the patient with additional written consent for future publication.

Figure 1 Preoperative radiograph showing great toe interphalangeal dislocation with divergent Lisfranc fracture dislocation.

The closed reduction of the interphalangeal dislocation was easily achieved under anesthesia which was later confirmed under fluoroscopy and the closed reduction of Lisfranc injury was achieved under fluoroscopic guidance. Two K-wires (2.0 mm) were introduced, one along the second metatarsal into the tarsal bones transfixing the Lisfranc joint. The other K-wire (1.0 mm) was introduced along the lateral TMT joints for added stability. The additional cortical screw (3.5 mm) was used for added stability from medial aspect and fixing the Lisfranc joint (Figure 2). The small wounds were dressed and a well-padded below knee plaster protection splint was applied following the confirmation of satisfactory alignment and fixation of the injuries. Elevation and non-weight bearing protocols were advised. Active toe and knee joint range of motion exercises were encouraged throughout the follow up. Gradual healing of the injury was noted in the follow-up along with reduction of swelling, pain and discomfort. The hardware were sequentially removed between 18-26 months postoperatively (Figure 3). The plaster splint was removed after eight weeks as swelling and pain were minimal. The only complication noted was hardware prominence of the medial screw that loosened over time and later was managed by its removal. The removal of K-wires and screw was uneventful at four and six month follow up. There was no re-dislocation of great toe noted and the patient was performing activities of daily living.

Figure 2 Postoperative radiograph showing the fixation of the Lisfranc injury with K-wire and screw from medial aspect along with reduced interphalangeal dislocation.

Figure 3 The follow up radiograph showing healed Lisfranc injury at the time of final hardware removal.

Discussion

Meticulous clinical and radiological assessment is critical for the diagnosis of Lisfranc injuries as these are notoriously missed in emergency settings and may be the reason for later medico-legal issues [5]. The divergent dislocation, as in our case, have characteristic radiographic deformity that makes it hard to miss and the diagnosis is evident. The divergent Lisfranc fracture dislocation is stated to be associated with fractures of other bones in the foot like the cuneiforms and navicular [6].The subtle injuries, the doubtful diagnosis and the requirement of looking for interposed structure interfering with reduction calls for use of imaging like computerized tomogram (CT) or magnetic resonance imaging (MRI) [7,8]. Our patient refused further imaging due to financial issues and urgent operative intervention was initiated. Open reduction-internal fixation (ORIF) and primary arthrodesis are two common techniques. Our method with use of closed reduction and percutaneous fixation with wires and screws resulted in primary arthrodesis of Lisfranc joint. The reported incidence of secondary procedures for complications has been found to be minimal with primary arthrodesis [9]. Studies have also shown good outcome of primary arthrodesis in comparison with ORIF in the long term [9,10]. Primary arthrodesis also obviates need for secondary arthrodesis in case of arthritis following either modality of treatment. Our minimal invasive approach resulted in early discharge and avoided wound complications.

Acknowledgement None

References

  1. Court-Brown CM, Caesar B. Epidemiology of adult fractures. A review. Injury, 2006;37(8):691-697. PubMed  
  2. Myerson MS, Fisher RT, Burgess AR, et al. Fracture dislocations of the tarsometatarsal joints: End results correlated with pathology and treatment. Foot Ankle.1986;6(5):225-242. PubMed
  3. Quenu E, Kuss G. Etude sur les subluxations du metatarse (luxations metatarsotarsiennes) du diastasis entre le 1stet le 2nd metatarsien. Rev Chir(Paris).1909; 39:281-336,720-791,1093-1134.
  4. Hardcastle PH, Reschauer R, Kutscha-Lissberg E, et al. Injuries to the tarsometatarsal joint. Incidence, classification and treatment. J Bone Joint Surg Br.1982;64(3):349-346. PubMed
  5. Chesbrough RM. Strategic approach fends off charges of malpractice: Program provides tips for avoiding litigation. Diagn Imaging 2002;24(13):44-51.
  6. Berquist TH, editor. Trauma. Radiology of the Foot and Ankle. New York: Raven Press, 1989. p. 191-7.
  7. Philbin T, Rosenburg G, Sferra JJ. Complications of missed or untreated Lisfranc injuries. Foot Ankle Clin North Am 2003;8:61-71. PubMed
  8. Kiuru MJ, Niva M, Reponen A, Pihlajamaki HK. Bone stress injuries in asymptomatic elite recruits: a clinical and magnetic resonance imaging study. Am J Sports Med. Feb 2005;33(2):272-276.
  9. Henning JA, Jones CB, Sietsema DL, et al. Open reduction internal fixation versus primary arthrodesis for lisfranc injuries: A prospective randomized study. Foot Ankle Int. 2009;30(10):913-922. PubMed
  10. Ly TV, Coetzee JC. Treatment of primarily ligamentous Lisfranc joint injuries: primary arthrodesis compared with open reduction and internal fixation. A prospective randomized study. J Bone Joint Surg Am.2006;88(3):514-520. PubMed

Osteochondromas of the subtalar joint: A case study

by Christopher Gaunder MD, Brandon McKinney DO*, Joseph Alderete MD, Thomas Dowd MD

The Foot and Ankle Online Journal 10 (3): 2

Osteochondromas are benign bone lesions derived from aberrant cartilage. Although osteochondromas represent one of the most common bone lesions, they rarely present in the foot and ankle. We report the case of a patient who presented with osteochondromas originating from the talus and calcaneus, representing a rare case of osteochondromas within the talocalcaneal joint, due to the location of the tumors and proximity of the lesions. After failure of conservative management, this patient underwent surgical excision followed with a planned arthrodesis for symptomatic peroneal impingement and subtalar arthrosis, both likely complications of the osteochondromata. We present this case as an example of the chronic complications associated with osteochondral lesions in hopes of promoting earlier management.

Keywords: osteochondroma, chondroma, talocalcaneal, kissing lesion

ISSN 1941-6806
doi: 10.3827/faoj.2017.1003.0002

1 – San Antonio Military Medical Center (SAMMC) in San Antonio, Texas, United States.
* – Corresponding author: bmckinney@westernu.edu


An osteochondroma is a benign chondrogenic lesion derived from aberrant cartilage. This is a primarily metaphyseal lesion of long bones (distal femur, proximal tibia, proximal humerus) and the pelvis [1,2]. Osteochondroma comprise the most common benign bone tumor and their overall incidence is unknown as many are asymptomatic and only detected once their mass effect manifests as a cosmetic deformity, mechanical symptom or symptom of neurovascular compression [2, 3]. Osteochondromas of the foot and ankle are uncommon except in rare cases of Multiple Hereditary Exostoses. Of these cases, only a few incidents of talar osteochondromas have been reported. To our knowledge, there are no prior reports of osteochondromas in such proximity of the talus and calcaneus [4].

Case Presentation

A 58-year-old female administrator presented with persistent pain at her left hindfoot.  Progressively worsening pain and stiffness over the prior 4-5 months were noted.  Nonoperative modalities such as brace-wear and NSAID use provided limited relief of pain and associated disability. She was unable to perform  High-impact activities and those on uneven ground secondary to pain.  On physical examination, there was near-complete restriction of subtalar motion which was associated with severe pain on active and passive hindfoot inversion and eversion.  She had a mild swelling over the anterolateral and posterolateral aspects of the ankle. Otherwise she demonstrated a benign musculoskeletal exam and was found to be without neurovascular impairment.

Radiographic examination demonstrated complete joint space loss at the posterior subtalar facet with subchondral sclerosis and subchondral cyst formation as well as a large well-circumscribed exostosis posterior to the subtalar joint (Figure 1).  Magnetic resonance imaging demonstrated bony excrescences at the posterior subtalar joint with disruption of the posterior facet articular surfaces. There was also underlying severe bone on bone degenerative change of the posterior facet with associated reactive edema within the talus and calcaneus (Figure 2). A cartilage cap to suggest osteochondroma was not appreciated. Two exostoses were noted to be extending posteriorly from the talus and calcaneus, respectively.  Marrow continuity between talus/calcaneus and their respective prominences was consistent with a presumptive diagnosis of osteochondroma.

Figure 1 Lateral and Mortise views of the left ankle demonstrate severe subtalar joint space narrowing with a well circumscribed pedunculated osseous lesion projecting posteriorly from the subtalar joint.

Figure 2 Sagittal imaging demonstrating a bony protuberance just posterior to the calcaneus with reactive edema about the osteochondroma as well as within the talus and calcaneus consistent with osteoarthritic changes. Axial MRI imaging demonstrates fragmentation within the osteochondroma indicative of two separate, but “kissing” lesions. The coronal image demonstrates the extensive osteoarthritic changes apparent in the subtalar joint of the patient.

Given the advanced nature of the lesion and failure of nonoperative modalities, surgical intervention was proposed. A midline incision was used , splitting the Achilles tendon centrally in a longitudinal fashion.  The mass was identified deep to the FHL with its enveloping bursa (Figure 3). The mass extended from the talus to the calcaneus.  The exostoses were removed at their base to the level of native contours of bone at both the talus and calcaneus (Figure 4). Subsequent inspection of the posterior facet of the subtalar joint demonstrated denuded cartilage with exposed subchondral bone.  Approximately 2mm of subchondral bone was removed.  A narrow osteotome was used to increase the exposed cancellous surface area.  A drill bit (2mm diameter) was used to create several channels between the surface and underlying cancellous bone.  Local autograft was then supplemented with an allograft demineralized bone graft substitute.  In situ compression and fixation was achieved with two 6.5mm partially threaded screws across the subtalar joint (Figure 5).  Histopathology of both specimens revealed linear columns of maturing chondrocytes within a cartilaginous cap and islands of cartilage within the bone of the stalk confirming the diagnosis of talocalcaneal osteochondromas on both sides of the  joint (Figures 6 and 7).  Post operatively the patient was treated with standard  protocol for subtalar joint arthrodesis. She was released to full weight-bearing and regular shoe wear three months from her date of surgery. At six month and one year follow up visits the patient had returned to full activities without difficulty or pain at her left hindfoot.

Figure 3 Intraoperative photo demonstrating the osteochondroma. The Achilles tendon was split longitudinally and retracted. The adjacent osteochondromas were then identified deep to the flexor hallucis longus, which was retracted medially to gain access to the lesions.


Figure 4 Removal of the osteochondromas about the posterior aspect of the subtalar joint with demonstration of exposed subchondral bone.


Figure 5 Lateral view of the left ankle demonstrating postoperative changes with removal of the talocalcaneal osteochondromas and subtalar arthrodesis.


Figure 6 Histopathology revealed cartilaginous island with an active chondrocyte surrounded by osteoid matrix of the attached bony stalk.

Figure 7 Photomicrograph of the cartilaginous cap at the margin of the exostoses demonstrates linear arrangement of active chondrocytes. Note the similar appearance to a normal physis seen in children.

Discussion

Osteochondromas are the most common benign bone tumor. They comprise 30 to 50% of benign bone lesion diagnoses and 15% of all bone tumors.  They represent a dislocation of growth plate cartilage, where normal longitudinal growth occurs adjacent to centripetal growth of the lesion in the metaphyseal region of bone. After growth plate closure there is typically no further growth of the lesions and the cartilage cap of osteochondroma mature to a maximal thickness of 2mm [5]. If lesions grow in adulthood they usually represent malignant transformation of the cartilage into chondrosarcoma [1, 6, 7]. Most osteochondromas grow from metaphyseal locations away from the adjacent joint. However, Trevor’s disease (Dysplasia Epiphysealis Hemimelica or DEH) or Fairbank’s disease are variants of osteochondromata in which the lesion is intra-articular and grows adjacent to joint cartilage [8].

There are several case reports demonstrating osteochondroma of adjacent metaphyseal regions developing concurrently, eventually leading to “kissing” lesions as the osteochondroma grow [1, 2, 4, 9]. There have also been reports of DEH “kissing” lesions which grow adjacent to an affected joint and lead to pain and presentation in childhood [6]. Osteochondromas have been reported in the literature adjacent to a periosteal chondroma forming a kissing lesion [7].

Most of these lesions present with innocuous swelling or pain, sometimes with movement restriction or mechanical compression. Finally, they can cause intra-articular loose body formation, ankle deformity, peroneal spastic flatfoot, limb length inequality or in adults with secondary arthritis [10].

When identified in a child, conservative management of these uniquely paired osteochondromas or periosteal chondroma is usually advocated, as surgical intervention for asymptomatic, intra-articular lesions may result in secondary arthrosis. Early surgical intervention has been advocated for metaphyseal or juxta-articular lesions to avoid complications with associated growth and deformity. In adults who present with a single osteochondroma, surgery is preferred due to the risk of malignant transformation or growth under a large tendinous sleeve at its metaphyseal insertion when a painful snapping syndrome can develop. One of the peculiarities that can develop in the adult with juxta-articular “kissing” lesions, especially in the lower extremity, is the proclivity towards arthrosis of the involved joint owing to abnormal contact stresses.  This was demonstrated in our patient who had subtalar arthrosis adjacent to peri-articular talar and calcaneal osteochondroma.

She may have had a Trevor’s lesion of the talus adjacent to more common osteochondroma or periosteal chondroma of the calcaneus. We observed joint effusion of the subtalar joint with high signal intensity of the adjacent talar and calcaneal bone identified on T2 and STIR sequencing as well as arthrosis on cartilage sequencing anterior to these lesions, presumably secondary to decreased mobility of the subtalar joint and a shift in the normal mechanical stresses anteriorly.

In our patient’s case, she presented with peroneal impingement and subtalar arthrosis. Thus she underwent excision of osteochondroma and subsequent subtalar fusion. Decompression alone without addressing the arthritis of the patient’s subtalar joint would lead to continued pain and potential need for a second surgical intervention.

We present this case as an illustration of the sequela associated with peri-articular osteochondromata of both the talus and calcaneus in the lower extremity.  We hope understanding the chronic complications associated with these lesions can facilitate earlier management prior to the development of late arthritic changes.

Conclusion

To the best of our knowledge this patient’s presentation represents a unique case of adjacent osteochondromata of the hindfoot that has not been reported previously in the literature. In this case the patient had symptomatic peroneal compression and subtalar arthrosis.  Although malignant degeneration is rare, the patient’s increased age at presentation placed her at higher risk of this complication. Given this risk and the patient’s presentation, surgical intervention was performed.   Awareness of such a case is important to consider when evaluating and treating hindfoot arthritis. This case highlights how careful surgical planning can appropriately evaluate for any malignant transformation while preventing the recurrence of this lesion and mitigating its complications.  

Funding Declaration No funding was acquired for this manuscript.

Conflict of Interest Declaration The authors declare that there is no conflict of interest regarding the publication of this manuscript.

References

  1. Ahmed AR, Tan TS, Unni KK, Collins MS, Wenger DE, Sim FH. Secondary chondrosarcoma in osteochondroma: report of 107 patients. Clin Orthop 2003 ; 411 : 193-206. (PubMed)
  2. Herrera-Perez M, De Mendoza M, De Bergua-Domingo J, Pais-Brito J. Osteochondromas around the ankle: Report of a case and literature review;  International Journal of Surgery Case Reports 4 (2013) 1025– 1027. (PubMed)
  3. O. Şahap Atik, M.D., Baran Sarıkaya, M.D., Cemalettin Kunat, M.D., Ramin Muradi, M.D., Bahadır Ocaktan, M.D., Hüseyin Topçu, M.D. Osteochondroma of the talus. Joint Diseases and Related Surgery. 2010;21(2):116-117. (Online)
  4. Chou LB, Ho YY, Malawer MM. Tumors of the foot and ankle: experience with 153 cases. Foot Ankle Int 2009;30(9):836–841.4. (PubMed)
  5. Marco RA, Gitelis S, Brebach GT, Healey JH. Cartilage Tumors: Evaluation and Treatment. J Am Acad Orthop Surg 2000;8:292-304. (PubMed)
  6. Murphey MD, Choi JJ, Kransdorf MJ, Flemming DJ, Gannon FH. Imaging of osteochondroma : variants and complications with radiologic-pathologic correlation. Radiographics 2000 ; 20 : 1407-1434. (PubMed)
  7. Wuisman PIJ, Jutte PC, Ozaki T. Secondary chondrosarcoma in osteochondromas:  Medullary extension in 15 of 45 cases. Acta Orthop Scand 1997 ; 68 : 396-400. (PubMed)
  8. Staals EL, Bacchini P, Mercuri M, Bertoni F. Dedifferentiated chondrosarcomas arising in preexisting osteochondromas. J Bone Joint Surg Am. 2007;89(5):987-993. (PubMed)  
  9. Singh R, Jain M, Siwach R, Rohilla S, Sen R, Kaur K. Large para-articular osteochondroma of the knee joint: a case report. Acta Orthop Traumatol Turc. 2012;46(2):139-143. (PubMed)
  10. Blair J, Perdios A, Reilly CW. Peroneal spastic flatfoot caused by a talar osteochondral lesion: a case report. Foot Ankle Int. 2007 Jun;28(6):724-6. (PubMed)

Foot anthropometrics in individuals with diabetes compared with the general Swedish population: Implications for shoe design

Tables Supplement

by Ulla Hellstrand Tang1,2 , Jacqueline Siegenthaler2, Kerstin Hagberg1,2, Jon Karlsson1, Roy Tranberg1

The Foot and Ankle Online Journal 10 (3): 1

Background: The literature offers sparse information about foot anthropometrics in patients with diabetes related to foot length, foot width and toe height, although these measurements are important in shoe fitting. A poorly fitted shoe is one of many contributory factors in the development of diabetic foot ulcers. The purpose of this study was to describe the foot anthropometrics in groups of patients with diabetes, in groups representing the general population and to explore whether foot anthropometrics differ between patients with diabetes and the general population.
Method: Foot anthropometrics (foot length, foot width and maximum toe height) was measured in 164 patients with diabetes, with and without neuropathy (n = 102 and n = 62 respectively). The general population was represented by 855 participants from two sources.
Results: Foot length, foot width and toe height varied (220-305 mm; 82-132 mm and 15-45 mm respectively) in the diabetic group and in the group representing the general population (194-306 mm; 74-121 mm and 17-31 mm respectively). Age, gender and BMI influence the foot anthropometrics, however, when adjusting for theses variables the index foot length/width was lower (2.58) in patients with diabetes without neuropathy vs. controls (2.63), p = 0.018. Moreover, patients with diabetes with neuropathy had wider feet (98.6 mm) compared with the controls (97.0 mm), p = 0.047.
Conclusions: The individual variations of foot length, foot width and maximum toe height were large. The impact of gender on foot anthropometrics was confirmed and the impact of age and BMI were shown. Patients with diabetes seemed to have a wider forefoot width and a lower foot length to foot width ratio compared to the controls.

Keywords: foot deformities, foot ulcers, footwear, prevention, shoe design, shoe lasts, diabetes, diabetic foot, anthropometrics

ISSN 1941-6806
doi: 10.3827/faoj.2017.1003.0001

1 – Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
2 – Department of Prosthetics and Orthotics, Sahlgrenska University Hospital, Gothenburg, Sweden.
* – Corresponding author: ulla.tang@vgregion.se


The biomechanical interaction between the foot and the shoe, three-dimensional appearance of the foot and the relationship between foot anthropometrics and the shoe have been shown to be important in the prevention of diabetic foot ulcers (DFU) [1-3]. In Sweden at the present time, foot measurements are not mandatory when patients are provided with therapeutic footwear at a department of prosthetics and orthotics (DPO). However, foot measurements are essential for the construction of the last upon which the shoe is created. In the 1950s, the Swedish Shoe Industry’s Research Institute (SFI) stated that the length and width of the foot should be measured before recommending any shoe to a customer [4]. Based on 8,000 foot measurements of Swedish men, the SFI constructed a standardized system, “the SFI last system”, which aimed to provide the majority of Swedish men with well-fitting shoes. This system included six different types of lasts, specified in three dimensions.

In patients with diabetes, the loss of protective sensation (peripheral neuropathy), together with poorly fitting shoes, increases the risk of developing DFU [3, 5, 6]. The risk is further increased by the presence of other risk factors, such as peripheral angiopathy, peripheral neuropathy, foot deformities, skin pathologies, previous ulcers or amputation or osteoarthropathy, Figure 1 [7, 8]. Based on the recommendations of the International Working Group on the Diabetic Foot (IWGDF), patients with diabetes, should have access to well-fitting shoes if they are at risk of developing DFU [5, 9]. Early prevention, together with well-fitting shoes, podiatry and access to specialists, has been shown to be successful. Bus and van Netten recently suggested that the target should be to reduce the incidence of DFU by 75% [10]. Their suggestion is based on a review of the scientific literature regarding the prevention of DFU recurrence. These authors found that interventions that included pressure-relieving therapeutic footwear, surgical interventions, home monitoring of foot temperature and, most importantly, adherence to treatment could produce a 75-80% decrease in DFU risk. The provision of adequate footwear is considered successful when it corresponds in every aspect to guidelines and recommendations relating to DFU prevention and care; i.e. a) when the patient finds the shoe acceptable, b) when the shoe has a design that accommodates all three dimensions of the foot and c) when the function of the shoe is satisfactory [9, 11-15]. A shoe that does not accommodate the length, width and height of the foot will be a potential risk factor for the onset of DFU. It has also been suggested that other factors, such as the patient’s age, gender and body dimensions expressed as body mass index (BMI), play an important role in shoe fitting [16-23].

Figure 1 The Swedish foot ulcer risk classification system. The one-page guideline illustrates the risk classes, the symptoms and the regional recommendations regarding interventions with podiatry, regular controls and footwear/orthotics [7].

In Sweden, the prescription of footwear for patients with diabetes at risk of developing DFU follows national and regional guidelines and patients are frequently referred to a certified prosthetist and orthotist (CPO) or an orthopaedic shoemaker for the prescription of adequate footwear [7]. The aims of the study were to describe the foot anthropometrics in groups of patients with diabetes and in groups representing the general population and to explore whether foot anthropometrics differ between patients with diabetes and the general population.

Method

Study design

This retrospective cohort study examined and compared foot anthropometrics (foot length, foot width and maximum toe height) in a group of patients with diabetes, Group D (n=164), with those of a control group of participants without known diabetes, Group C (n=855), representing the general population (Figure 2).

Figure 2. Study population. Presentation of the number of patients included in the two study groups derived from studies of patients with diabetes and studies of foot anthropometrics (the control group). The year when the measurements were obtained are shown in the figure.

Participants

A total of 1,019 participants were included in the present study. All patients in Group D were referred to a DPO by a medical doctor. Their feet were recognised as being at risk of DFU and the patients were provided with therapeutic footwear or insoles at the DPO. The participants have previously been described [24, 25]. Group D was split into two sub-groups, one comprising patients with peripheral neuropathy (DN) and one comprising patients without neuropathy (DD), Figure 2.

Group C comprised participants from two sources. One group consisted of participants from unpublished research from the SFI, Group C1. These data are stored at ArkivCentrum in Örebro, Sweden. The other group consisted of participants that have previously been presented by Hansson et al., Group C2 [26].

Group D

Foot anthropometrics, age and gender in Group D were registered by nine experienced CPOs. All patients were at risk of developing DFU according to the Swedish DFU risk classification system (Figure 1) [7, 8]. The patient’s body height and weight were self-reported. Neuropathy was diagnosed following international recommendations using a set of measurements [27, 28]. In detail, neuropathy was considered present if at least one of the following tests demonstrated a positive finding a) the 10 g monofilament test, vibration test using a tuning fork C128 Hz, the slight touch of a pencil, or awareness of different positioning of the hallux or b) a tingling or numb feeling in the feet, a positive Ipswich Touch Test or self-reported answers from the patients that their feet were currently less sweaty compared with recent years [27-29]. Forty-two (58%) of the women and 60 (66%) of the men had neuropathy. A total of 51 of the 164 (31%) patients were diagnosed with diabetes type 1.

Control Group C1

Foot anthropometrics, age and gender were registered in Group C1, (n=488). A randomly selected cohort, 200 women and 200 men respectively, from a total of 2,382 (546 women and 1,836 men) individuals were analysed. The measurements were collected in Sweden 1972-1977 by the SFI [30, 31]. The women included in the cohort worked at shoe factories or offices and the men in the cohort were in the military service. The measurements of the conscripts were made by three different investigators in a project managed in collaboration with the Swedish Defence Materiel Administration [30]. The foot measurements of the retired persons and the 200 women were registered and examined by one investigator employed at the SFI. A further set of 88 measurements, registered by SFI, from retired persons was included.

Control group C2

Foot length, foot width, age, gender, height and weight were registered in Group C2 [26]. The foot anthropometrics in Group C2, 262 women and 105 men, were measured by trained personnel in 2006. Body height was measured using a rigid measuring tape attached to the wall. Body weight was measured with a digital measurement device with an accuracy of 0.1 kg. The raw data were obtained from Skövde University and Chalmers University of Technology, Gothenburg, Sweden [26].

Foot anthropometrics

The definition of foot length and width used in present study is described in Table 1 (all tables are included in attached Supplement PDF) and illustrated in Figure 3. The equipment, measurement and methods used in the sub-groups are reported in Table 1, together with information on the accuracy of the measurements. In Group D, foot length and foot width were measured with a standardised calliper (Fotmått, model Hyssna, Jerndahls Skinn & Läder; Kumla, Sweden, and Footy, article number 500210, Brunngård, Borås). In Group C1, a special foot measurement apparatus (Figures 4 and 5) was used to measure foot length and ball width. The foot of the participants in Group CI were fixed in the foot measurement device and aligned in a local coordinate system with the foot length axis (line) projected from the posterior part of the middle of the heel through an interdigital point between digit 1 and digit 2. It is noteworthy that the measurements of foot length using this technique placed the heel in an 18 mm heel height position and the length measured was the projected foot length, Figure 3. The projected foot length is approximately 0.6 mm shorter than a measurement obtained with zero heel height. The only exception from this routine was the measurement of foot length and ball width in 97 conscripts, year 1975, and in the group of retired persons. These measurements were obtained using a special body calliper device, an anthropometer [32]. In Group C2, a rigid measuring tape was used to measure foot length and foot width with an accuracy of ± 2 mm. In Group C1, the measurements of the width of the forefoot, made by the SFI, are by definition the ball width, a line from the inner ball point to the outer ball point, Figure 3. To calculate a comparable measurement of foot width, perpendicular to foot length, the following equation was used: f(fw)= cos α * bw where fw is the foot width, α is the ball angle and bw is the ball width. The maximum toe height, a measurement for identifying the foot deformity “hammertoes” (Figure 6), was introduced and measured using a ruler. The SFI reported a standard error of the mean of 0.18 mm [4] for the toe height measurement and Hellstrand et al. found a mean difference of 0.5 mm [25]. In Group D, digits 1-5 were measured and, in Group C1, toe height (digits 2-4) was measured in 200 women.

Figure 3 Definition of foot measurements. Foot length: the line, parallel to the foot axis, from the posterior heel point to the most distal toe point. The line passes through the centre of metatarso-phalangeal joint 2. Foot width: measured to the foot axis perpendicularly as the projected length of the distance in the forefoot through the centre of the first metatarsal head to the lateral side. Ball width: the line from the inner to the outer ball point. Ball angle: the space between the two intersecting lines “foot width” and “ball width”.

Figure 4 Foot measuring apparatus. The foot measurement apparatus was constructed to measure 21 foot anthropometrics (length, width, heights and angles). It was developed by Nils Haraldsson and used by the Swedish Shoe Industry’s Research Institute. Between 1940-1990, the feet of 16,000 people in Sweden were measured. The right foot was placed naked and with the planta horizontally on the measurement device and fixed with a metal plate between the hallux and the 2nd toe. The posterior part of the heel rested against a bar. Subjects stood with their weight equally distributed between both feet. The heel height was fixed at 18 mm. Foot length was measured with a bar mounted perpendicular to a longitudinal scale. A turnable scale mounted on the longitudinal scale was used for measurements of ball width. All measurements at the SFI were performed with the same measurement device. Photographer Curt Götlin 1951/Örebro stadsarkiv. 

Figure 5 Foot measuring apparatus in detail. Foot measurement apparatus developed by Nils Haraldsson and used by the Swedish Shoe Industry’s Research Institute. Between 1940-1990, the feet of 16,000 people in Sweden were measured. Photographer Curt Götlin 1951/Örebro stadsarkiv. Homepage available 2016-04-22 The apparatus can be seen at the Kumla Skoindustri Museum. 

Patients reported experience measure

A subgroup (n = 97) of the patients with diabetes was interviewed by a research assistant, following a structured protocol, regarding how much they had used the footwear and how they experienced wearing the footwear

Statistical analysis

General demographics and the foot anthropometrics (length, width and maximum toe height) in the four groups are reported using the mean and standard deviation (SD). Due to dependency between the right and the left foot, only the right foot was analysed. Measurements with invalid data were excluded. Differences between groups regarding foot anthropometrics were examined in the following three comparisons.

Comparison 1 examined whether there were differences between groups (DN, DD, C1 and C2) in the dependent variables (foot length, foot width, indexFL/FW and maximum toe height respectively). One-way analysis of variance (ANOVA) was used, followed by multiple comparisons. By using residual plots and Q-Q plots, the assumptions of the analyses were analysed. The variable maximum toe height had minor deviations from the assumptions, with a skewed distribution of the residuals and the logarithmic value was therefore used for all further analysis.

Comparison 2 examined whether there were differences between groups regarding the dependent foot variables, considering the covariates of age and gender.

Comparison 3 examined whether there were differences between groups regarding the dependent foot variables, considering the covariates of age, gender and BMI.

In comparisons 2 and 3, the covariates were added in a linear mixed model with fixed effects with factors (study groups and gender) and quantitative variables (age and BMI). The above-mentioned foot anthropometrics were dependent variables. Differences between groups were corrected for differences regarding the covariates of age, gender and BMI. Group C2 was excluded in comparison 2 in terms of the maximum toe height analysis (toe height had not been measured) and Group C1 was excluded in comparison 3 (height and weight had not been measured).

Excel 2010, SPSS 22 and SAS version 9.3 (SAS Institute Inc.Cary, N.C., USA) software were used. The SAS procedure, MIXED with LSMEANS and ESTIMATE statements, statistical tests and comparisons of population marginal means were used in the comparative analyses. In the following text, the term “analysis of covariance” is used to describe the method.

Results

The demographics showed that participants with diabetes were older and had a higher BMI (women: 61 ± 14.4 years BMI 26.7 ± 4.9; men: 63 ± 13.7 years BMI 28.7 ± 5.2) compared with the participants representing the general population (women: 41 ± 16.5 years BMI 23.1 ± 3.4; men: 34 ± 17.9 years BMI 24.1 ± 3.5). A full presentation of the participants is given in Table 2. In Table 3, the details (HbA1c and duration) of patients with diabetes are presented.

The analysis of foot anthropometrics was based on 164 measurements in Group D and 855 measurements in Group C, Figure 2. The exploration of foot anthropometrics revealed that, among women, the foot length varied from 245.4 ± 10.9 mm (Group DD) to 242.3 ± 12.3 mm (Group C2) and the width varied from 96.8 ± 4.9 mm (Group DD) to 90.9 ± 7.7 mm (Group C1), Table 4. Women with diabetes with neuropathy had the largest toe height (25.8 ± 4.6 mm).

The foot length among men varied from 271.4 ± 15.2 mm (Group DN) to 262.7 ± 13.7 mm (Group DD). Moreover, the width varied from 105.8 ± 7.9 mm (Group DN) to 98.8 ± 5.7 (Group C1). Men in Group DN had the largest toe height (28.3 ± 5.7 mm).

The individual variation in foot anthropometrics in patients with diabetes was: foot length (220-305 mm), foot width (82-132 mm) and toe height (15-45 mm) and the variation in the control group was foot: length (194-306 mm), foot width (74-121 mm) and toe height (17-31 mm).

The first comparison of differences between groups revealed that patients in Group DN had 11.0 mm longer feet compared the controls in Group C2 (p ≤ 0.001). The controls in Group C1 had 5.5 mm longer feet than the controls in Group C2 (p ≤ 0.001). Foot width in patients with and without neuropathy was wider (101.5 mm and 99.6 mm respectively) compared to the controls ((94.7 mm and 94.4 mm respectively, (p ≤ 0.001). Maximum toe height was higher in patients with diabetes and neuropathy (26.9 mm) compared with the controls in Group C1 (25.2 mm) (p ≤ 0.001).

In the second comparison, considering the effect of age and gender on foot anthropometrics, only the indexFL/FW was unaffected by age and gender and the covariate of age did not affect foot length. However, regarding foot width, both men and women had an estimated annual increase in width of 0.085 mm/year and men generally had 9.0 mm wider feet than women. Maximum toe height was affected in a similar way. Men had a 0.09 mm higher maximum toe height compared with women. With age, the increase in toe height was 0.03 mm annually. Group DN had a larger toe height (25.5 mm) than Group DD (24.4 mm), p = 0.049. Furthermore, Group DD had a lower toe height than Group C1 (27.1 mm), p ≤ 0.001. Foot width, adjusted for age and gender was wider in patients with diabetes compared to the controls and accordingly the indexFL/FW was higher in the groups representing the general population compared to the diabetics.

The third comparison revealed that gender and BMI affected foot length and foot width. With every unit increase in BMI, foot length and foot width increased by 0.6 mm. Adjusting for these covariates, foot width still differed comparing Group DN with Group C2 (98.6 mm vs. 97.0 mm), p = 0.047. The indexFL/FW differed when comparing Group DD (2.58) with Group C2 (2.63) p = 0.018.

Patients reported experience measure

Eighty-six out of a total of 97 patients (response rate 89%) participated in the interview at three months after the visit to the DPO (Table 6). Thirty patients had been provided with footwear and among those 70% had used their therapeutic footwear often or all the time and 76% stated they were content or very content with the footwear. Twenty-nine patients made comments, Table 7. Seven of the comments were categorized as complaints related to the footwear, such as “The shoe appears to be too large”. Ten patients reported that the use of footwear and/or foot orthoses was dependent on the season and location (indoors or outdoors).

Discussion

To our knowledge, this is the first study presenting foot anthropometrics in patients with diabetes and the general population in terms of foot length, foot width, indexFL/FW and maximum toe height. Foot length, foot width and toe height varied in the diabetic group (220-305 mm; 82-132 mm and 15-45 mm) and in the group representing the general population (194-306 mm; 74-121 mm and 17-31 mm). Patients with diabetes had wider feet compared to the participants representing the general population. The main finding is that several factors affect foot anthropometrics and include the presence of diabetes, neuropathy, gender, age and BMI.

The maximum toe height measurement is of special interest when it comes to preventing foot ulcers in patients with diabetes (Figure 6). Large toe height is typical of a hammer-toe deformity. This deformity with dorsal flexion of the metatarsal phalangeal joint and plantar flexion of the interphalangeal joints, causes high peak pressure to certain areas of the toe [33]. Measurements of maximum toe height provide important information and guidance in the selection of a shoe with an appropriate toe box height relative to the maximum individual toe height. A threshold value of 25 mm is suggested, based on toe box heights common in off-the-shelf shoes, ranging from 22-26 mm [34]. The range for toe box height and the suggested threshold value correspond well to the toe box heights (24.5-28.5 mm) standardised in the SFI lasts for men with a foot length of 260 mm [4]. Patients with a toe height of greater than 25 mm should be identified and provided with shoes with a toe box height that allows the toes to move without limitation [35].

Figure 6 Hammertoe deformity. A hammer toe deformity with areas of of high pressure indicated by the red areas. The structural changes is a combination of the flexion of the the interphalangeal joints and the extension of the metatarsal phalangeal joints.

Foot anthropometrics appeared to be affected by age. Based on the presented data, the toe height age coefficient of 1.003 indicates an annual increase in maximum toe height of 0.3% (Table 5). A simulation of an increment in toe height implies that a person who, at the age of 20, has a maximum toe height of 25 mm would, at the age of 40 years, have a toe height of 27.8 mm (a total increase of 10.4%). At the age of 80 years, the maximum toe height would be 29.2 mm (a total increase of 15.5%).

The effect of age on foot width was not statistically significant when all three covariates (age, gender and BMI) were included in the model. However, Tommassoni et al. measured ball forefoot circumference as a combined width and height measurement and found an increase with age [22]. In their study, older women (65-75 years) had a larger forefoot circumference, 235.4 ± 8.3 mm, compared with. younger women (25-35 years) 217.2 ± 11.5 mm. Tommassoni found similar results for older men (256.4 ± 7.8 mm) vs. younger men (242.1 ± 17.4) [22]. A well-fitting shoe, with good function, should correspond to the forefoot width and the forefoot circumference to avoid pressure-induced DFU in the forefoot. Previous findings shows that unfortunately, wearing ill-fitting shoes that are too narrow, are common [36].

The CPOs and orthopaedic shoemakers play an important role in guiding patients towards choosing an appropriate shoe. In this context, foot measures obtained on regular basis, are a good starting point for a discussion between the CPO and the patient regarding shoe lasts that fit the foot according to foot length, foot width and toe height.

Not surprisingly, gender was a covariate of importance to explaining the variation in foot anthropometrics in terms of foot length and foot width. Both measurements, length and width, were larger in men than in women (comparison 2, Table 5) and the results confirm previous findings of gender differences, showing that men in generally have longer and wider body segments than women [22, 37-39]. Several shoes are designed for unisex purposes and it is reasonable to consider whether shoes manufactured on such lasts actually fit both men and women [40]. The findings in the present study show gender differences for all three dimensions of the foot.

Possible systematic errors in measurement technique (tools and personnel) and/or sample bias might affect the validity of the data. The foot measurement apparatus developed and used by the SFI was designed to obtain robust measurements on thousands of people in Sweden half a century ago. These measurements had high precision   (Table 1). The measurement error reported in Group C1 was small (± 0.14 mm) in terms of the foot length. Measurements and the accuracy of foot length and foot width, measured with a rigid measuring tape in Group C2 was acceptable ± 2 mm [26]. The  mean difference regarding foot length and foot width measurements in Group D was (0.2 and 0.7 mm respectively), which indicates that the method used was reliable [25]. The method for measuring foot width was similar in Group D and Group C2. The foot width in Group C1 was derived from the ball width measurements, Table 1 and Figure 3 [30]. Due to the high accuracy of the ball width measurements (± 0.06 mm) the calculated foot width measurement is considered to be high [4]. The measurement error in toe height measurement was acceptable in Group C1 (± 0.18 mm) and in Group D (a mean difference of ± 0.5 mm).

The lack of anthropometric foot data of greater sample sizes was the reason for the use of several data sources, some of older date. The data from SFI was considered to be of high quality as the foot anthropometrics in Group C1 was obtained by the use of a well-established technique with high accuracy [30-32, 37, 41].

A certain question of interest is whether the participants born at later date, in general, had longer body segments and longer feet. This might be an expression of the secular trends [4, 42-44]. In that case, a consequence should be that the general population born in the 1960s (Group C2) would have longer feet than the older population born in the 1930s (Group C1). However, no such difference was supported in the present data.

Patients with diabetes and neuropathy appeared to have longer feet (comparison 1) and higher toe height (comparison 2). However, due to multiple comparisons the p-value is not convincing and this finding need to be confirmed in larger studies. Moreover, the test of assessing neuropathy in current study did not discriminate between slight and severe expressions of neuropathy. It is reasonable to expect that imbalance of muscle forces leading to foot deformities is related to the severity of neuropathy.

Patients reported experience measure

The majority of the patients who received therapeutic footwear used the footwear frequently and were satisfied with the footwear. However, the standardized routine used in the interview has not been validated. It is suggested that a combination of interviews and validated surveys should be used in coming studies [45]. Bus and van Netten showed that adherence to the prescribed intervention is a primary factor for successful treatment of DFU, i.e. the provision of adequate footwear is only successful if the patient uses the shoes [10]. Consequently, the patient must find the shoe suitable according to his/her preferences, and the shoe must have a shape and function suitable for the foot, considering the general recommendations in terms of DFU prevention and care [9, 11]. This is a challenge as, besides being an assistive devices [46], footwear is part of the patient’s personal attributes and identity.

Statistical considerations

The results of the three comparisons (ANOVA analysis and the following two analyses of covariance) were not adjusted for multiple comparisons, i.e. some of the differences may have appeared by chance. Therefore, the p-value increased when the covariates of age, gender and BMI were included in the model. Prospective longitudinal studies, including larger cohorts, are suggested to confirm the findings of the present study. All four study groups were included in the first comparison of differences in foot anthropometrics between groups. However, due to lack of data of height and weight, C1 was excluded in comparison 3, the analysis in which BMI was considered. In the comparison of maximum toe height, Group C1 was represented by a cohort of 200 women and Group C2 was not included due to lack of relevant data.

Shoe design

Large individual diversity, in terms of foot length, width and maximum toe height, was present in patients with diabetes with and without neuropathy. Moreover, age, gender and BMI influence the foot shape of individuals. All these aspects need to be considered in shoe design. The shoe last must correspond to the three-dimensional appearance of the foot, allowing the forefoot and the toes to move [36, 47].  Appropriate fit at the hindfoot and midfoot is also essential to ensure that the shoe stays on the foot [4].

One basic prerequisite for functional shoe design is an appropriate knowledge of foot biomechanics [5, 36, 48]. This is of utmost importance when manufacturing shoes for patients at risk of developing DFU. In order to enhance the shoe-fitting procedure, standardised routines including regular measurements of foot anthropometrics are suggested. This should preferably be supplemented by a shoe measurement specification from the manufacturer. Moreover, a thorough documentation of foot anthropometrics in patient’s medical record would facilitate a long-term provision and follow-up.

To highlight the need for standardisation, the following example of shoe length in relation to foot length is presented. The recommendation for how much longer a shoe should be in relation to the longest toe, found in the literature, varies and ranges from 10 to 20 mm [35, 49]. In clinical practice in Sweden, an extra length of 10 mm is recommended in relation to the foot length of adults, measured in a weight-bearing position [50].

The indexFL/FW needs to be rediscovered and used in shoe fitting. This measurement was recommended by the SFI and was used in shoe shops in the 1950s to 1970s, before an appropriate shoe last was chosen for the customer. The indexFL/FW gives a two-dimensional ratio, which is of great interest and assistance before a suitable last type is selected for patients [4, 47, 49]. When custom-made orthopaedic shoes are required a further set of measurements are needed [4].

In the development of good practice to prevent DFU, some attempts have been made to structure the provision of footwear and therapeutic footwear [35, 51]. Dahmen et al. developed a matrix of the features to be included in a therapeutic shoe, e.g. rocker bar, outsole, shaft flexibility, shaft height, insole and heel counter, corresponding to the identified risk factors for the onset of DFU. These risk factors were loss of protective sensation, autonomic dysfunction, limited joint motion, hollow-claw foot, Charcot deformity and hallux amputation [11, 52]. A limitation in the matrix was the lack of foot anthropometrics, such as length, width, the indexFL/FW or maximum toe height. However, length measurement was included in the footwear assessment tool presented by Barton et al., but this tool did not include the width or maximum toe height [51].

Conclusion

The individual variations of foot length, foot width and maximum toe height were large. The impact of gender on foot anthropometrics was confirmed and impact of age and BMI was found. Patients with diabetes seemed to have wider forefoot width and a lower foot length/foot width ratio compared to the controls. Standards for measurements of foot length, foot width and toe height should be developed and used at the DPOs. Accordingly, shoes designed for patients with diabetes should include the same standardised information as the foot measurements.

Declarations

Abbreviations

BMI; body mass index, DFU; diabetic foot ulcers, CPO; certified prosthetist and orthotist, C; control, DPO; department of prosthetics and orthotics, D; diabetes, IWGDF; International Working Group on the Diabetic Foot, SD; standard deviation, SFI; the Swedish Shoe Industry’s Research Institute

Acknowledgement

The authors would like to thank all the personnel at ArkivCentrum Örebro län, Örebro stadsarkivs bildarkiv and Skoindustrimuseet in Kumla for their contribution of data and pictures. We are also grateful for the collaboration with Erik Brolin, Chalmers University of Technology, Gothenburg, Lars Hanson at the University of Skövde and Chalmers University of Technology, Gothenburg, and Dan Högberg at the University of Skövde. We would also like to thank all the patients for their contribution to the study. Without the help of all the co-workers at the DPO Sahlgrenska University Hospital, Gothenburg, the DPO Södra Älvsborgs Sjukhus, Borås, the DPO NU-sjukvården, Trollhättan/Uddevalla, and the DPO Skaraborgs Ortopedservice AB, Skövde, all situated in the Västra Götaland Region in Sweden, this study would never have been possible; thank you all. Finally, we would like to thank Pontus Andersson for the illustration.

Funding

This research was supported 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 and Sveriges Ortopedingenjörers Förening.

Availability of data and material

The data sets supporting the conclusion of this article are included in the article.

Authors´ contribution

UT designed the study, researched the data, contributed to discussions, and wrote the manuscript. JS and RT designed the study, researched the data, contributed to discussions, reviewed and edited the manuscript. KH and JK contributed to discussions, reviewed and edited the manuscript.

Authors´ information

UT and JS are certified prosthetists and orthotists at the department of Prosthetics and Orthotics, Sahlgrenska University Hospital. Moreover, UT is a podiatrist. KH is registered physiotherapist at the department of Prosthetics and Orthotics, Sahlgrenska University Hospital and Associate Professor at the department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University. JK is chief physician at the department of Orthopaedics, Sahlgrenska University Hospital and Professor at the department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University. RT is certified prosthetists and orthotists at Lundberg Laboratory for Orthopaedic Research, at Sahlgrenska University Hospital. All are situated in Gothenburg, Sweden.​

Competing interest

The authors declare that they have no competing interests.

Consent for publication

Not applicable.

Ethics approval consent and permission to participate

The study was approved by the Gothenburg Regional Ethical Review Board (299-07, 461-12 and 1041-13). Patients were informed of the study design before they provided written consent.

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  52. Dahmen R, van der Wilden GJ, Lankhorst GJ, and Boers M. Delphi process yielded consensus on terminology and research agenda for therapeutic footwear for neuropathic foot. J Clin Epidemiol 2008; 61: 819-26.
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Summer 2017


Issue 10 (2), 2017


Isolated, nondisplaced medial cuneiform fractures: Report of two cases
by Koun Yamauchi MD, Satoru Miyake MD, Chisato Kato MD, Takayuki Kato MD


Radiographic changes in coronal alignment of the ankle joint immediately after primary total knee arthroplasty for varus knee osteoarthritis
by Ichiro Tonogai, Daisuke Hamada, Koichi Sairyo


Trigger events for Charcot neuroarthropathy: A retrospective review
by Brent H. Bernstein DPM FACFAS, Payel Ghosh DPM, Colleen Law DPM, Danielle Seiler DPM, Thuyhien Vu DPM


The D-Foot, for prosthetists and orthotists, a new eHealth tool useful in useful in risk classification and foot assessment in diabetes
by Ulla Hellstrand Tang BSc, Roy Tranberg PhD, Roland Zügner BSc, Jon Karlsson MD PhD, Vera Lisovskaja PhD, Jacqueline Siegenthaler BSc, Kerstin Hagberg PhD


Effects of medial and lateral orthoses on Achilles tendon kinetics during running
by Gareth Shadwell, Jonathan Sinclair


Effects of medial and lateral orthoses on Achilles tendon kinetics during running

by Gareth Shadwell1, Jonathan Sinclair1*

The Foot and Ankle Online Journal 10 (2): 5

The aim of the current investigation was to determine the effects of medial and lateral foot orthoses on Achilles tendon kinetics. Achilles tendon kinetics were obtained from twelve male runners who ran at 4.0 m/s, in lateral, medial and no-orthotic conditions. Achilles tendon loading parameters in the three orthotic conditions were examined using one-way repeated measures analysis of variance (ANOVA). The results showed that peak Achilles tendon force was significantly reduced in the medial (49.96 N/kg) in relation to the lateral (54.32 N/kg) and no-orthotic (53.90 N/kg) conditions. In addition, it was also shown that Achilles tendon load rate was significantly reduced in the medial (400.25 N/kg/s) in relation to the lateral (444.11 N/kg/s) and no-orthotic (431.30 N/kg/s) conditions. The current investigation therefore indicates that that medial orthoses can significantly attenuate Achilles tendon loading parameters linked to the etiology of Achilles tendon pathologies. Further study is required to determine whether reductions in Achilles tendon load as a function of medial orthoses also serve to reduce the risk of developing Achilles tendon pathology.

Keywords: biomechanics, Achilles tendon, orthoses, running, sport

ISSN 1941-6806
doi: 10.3827/faoj.2017.1002.0005

1 – Centre for Applied Sport and Exercise Sciences, School of Sport and Wellbeing, Faculty of Health & Wellbeing, University of Central Lancashire, Lancashire, UK.
* – Corresponding author: jksinclair@uclan.ac.uk


Tendons consist of mostly type I collagen and elastin embedded in a proteoglycan-water matrix with collagen; the comprises 65–80% and elastin and approximately 1–2% of the dry mass of the tendon [1]. The Achilles Tendon (AT) is the strongest and thickest tendon in the human body; it originates from near the middle of the calf and is the conjoint tendon of the gastrocnemius and soleus muscles [2]. The AT is subjected to the highest repetitive loads of any tendon within the body, with tensile loads up to ten times an individual’s body weight during running, jumping, hopping, and skipping [3]. The AT can experience loads in excess of 5 body weights (BW) during a standard running gait [4]; whist Achilles tendinopathy represents 9.5% of all running injuries sustained [5]. This can be attributed to degeneration of the collagen and elastin that comprise the structure of the AT through the cyclical nature of loading in physical activities such as running.

In-shoe orthotics designed to adjust the relative position of the calcaneus are traditionally used in rehabilitation methods post AT injury; the elevation of the calcaneus causes increased plantar-flexion and the shortening of the muscle-tendon unit, therefore reducing AT load during gait [6]. Using appropriate and well-fitting orthoses has been shown to improve walking and running function during activities in daily lives [7]. Lorimer and Hume., [8] identified two variables which showed strong evidence of reduction of loads experienced by the AT during running activities; these were high vertical forces and high medial foot arch. They also identified that surface stiffness may have had an effect on AT load and risk of injury.

The force distribution of the triceps surae coupled with the position of the calcaneus has been theorised to have an effect on the strain differences of the AT between individuals [9]; indicating that manipulation of the calcaneus position could affect the distribution of force through the foot. Functional foot orthoses are intended to aid in the correction of biomechanical abnormalities of an individual and reduce the likelihood of the occurrence of injuries as a result of the abnormality. The effects of orthoses on the reduction of AT loads have been studied extensively in a range of locomotion activities; Hockings and Nester., [10] determined that the use of dorsal ankle orthoses reduced vertical ground reaction force (GRF) during locomotion activities when compared with the same motion without the orthotic insert. However, Fröberg et al., [11] produced results that showed that weight bearing in ankle-foot orthoses which restrict dorsiflexion potentially could result in increased forces in the Achilles tendon compared with barefoot walking. Donoghue et al., [12] found that the use of an orthotic resulted in an average reduction of symptoms brought on by a chronic AT injury of 92%; indicating that orthoses when used correctly can aid in the treatment of chronic AT injuries brought on by repetitive loading activities.

However, there has yet to be any published information concerning the effects of medial and lateral orthoses in the reduction of AT load. Therefore, the aim of the current investigation was to determine the effects of medial and lateral foot orthoses on AT kinetics. This could lead to the assertion as to whether medial or lateral orthoses are a viable method of reducing AT load; potentially reducing the incidence of AT injuries.

Methods

Participants

Twelve male runners (age 26.23 ± 5.76 years, height 1.79 ± 0.11 cm and body mass 73.22 ± 6.87 kg) volunteered to take part in this study. All runners were free from musculoskeletal pathology at the time of data collection and were not currently taking any medications. The participants provided written informed consent in accordance with the principles outlined in the Declaration of Helsinki. The procedure utilized for this investigation was approved by the University of Central Lancashire, Science, Technology, Engineering and Mathematics, ethical committee.

Orthoses

Commercially available orthotics (Slimflex Simple, High Density, Full Length, Algeos UK) were examined in the current investigation. The orthoses were made from Ethylene-vinyl acetate and had a shore A rating of 65. The orthoses were able to be modified to either a 5˚ varus or valgus configuration which spanned the full length of the device.  

Procedure

Participants ran at 4.0 m/s (±5%), striking an embedded piezoelectric force platform (Kistler, Kistler Instruments Ltd., Alton, Hampshire) with their right foot [13]. Running velocity was monitored using infrared timing gates (Newtest, Oy Koulukatu, Finland). The stance phase was delineated as the duration over which 20 N or greater of vertical force was applied to the force platform [14]. Runners completed a minimum of five successful trials in each footwear condition. The order that participants ran in each footwear condition was randomized. Kinematics and ground reaction forces data were synchronously collected. Kinematic data was captured at 250 Hz via an eight camera motion analysis system (Qualisys Medical AB, Goteburg, Sweden). Dynamic calibration of the motion capture system was performed before each data collection session.

To define the segment coordinate axes of the right foot and shank. Carbon fiber tracking clusters were positioned onto the shank segment, whilst the foot was tracked using the 1st metatarsal, 5th metatarsal and calcaneus markers. The centers of the ankle and knee joints were delineated as the midpoint between the malleoli and femoral epicondyle markers [15,16]. Static calibration trials were obtained with the participant in the anatomical position in order for the positions of the anatomical markers to be referenced in relation to the tracking clusters/markers. A static trial was conducted with the participant in the anatomical position in order for the anatomical positions to be referenced in relation to the tracking markers, following which those not required for dynamic data were removed.

Processing

Dynamic trials were digitized using Qualisys Track Manager in order to identify anatomical and tracking markers then exported as C3D files to Visual 3D (C-Motion, Germantown, MD, USA). Ground reaction force and kinematic data were smoothed using cut-off frequencies of 25 and 12 Hz with a low-pass Butterworth 4th order zero lag filter.

Data during the stance phase of running were exported from Visual 3D into OpenSim software (Simtk.org), which was used give to simulations of muscles forces. Simulations of muscle forces were obtained using the standard gait2392 model within Opensim v3.2. This model corresponds to the eight segments that were exported from Visual 3D and features 19 total degrees of freedom and 92 muscle-tendon actuators.

We firstly performed a residual reduction algorithm (RRA) within OpenSim, this utilizes the inverse kinematics and ground reaction forces that were exported from Visual 3D. The RRA calculates the joint torques required to re-create the dynamic motion. The RRA calculations produced route mean squared errors <2°, which correspond with the recommendations for good quality data.  Following the RRA, the computed muscle control (CMC) procedure was then employed to estimate a set of muscle force patterns allowing the model to replicate the required kinematics [17]. The CMC procedure works by estimating the required muscle forces to produce the net joint torques.

Achilles tendon force (ATF) was estimated in accordance with the protocol of Almonroeder et al., [18] by summing the muscle forces of the medial gastrocnemius, lateral, gastrocnemius, and soleus muscles. All Achilles tendon load parameters were normalized by dividing the net values by body mass (N/kg). Achilles tendon load rate (N/kg/s) was quantified as the peak ATF divided by the time to peak ATF. Finally, Achilles tendon impulse (N/kg·s) during the stance phase was quantified by multiplying the force during the stance phase by the stance phase duration.

Statistical analyses

Means, standard deviations and 95% confidence intervals were calculated for each outcome measure for all footwear conditions. Differences in ATF parameters between footwear were examined using one-way repeated measures ANOVAs, with significance accepted at the P≤0.05 level [19]. Effect sizes were calculated using partial eta2 (pη2). Post-hoc pairwise comparisons were conducted on all significant main effects. In addition to this percentage differences were also calculated for all statistically significant effects. The data was screened for normality using a Shapiro-Wilk which confirmed that the normality assumption was met. All statistical actions were conducted using SPSS v23.0 (SPSS Inc., Chicago, USA).

Results

A significant main effect (P<0.05, pη2 = 0.33) was shown for the peak ATF. Post-hoc pairwise comparisons showed that peak ATF was significantly lower in the medial orthosis in relation to the lateral and no-orthotic condition. In addition a significant main effect (P<0.05, pη2 = 0.31) was observed for ATF load rate (Table 1, Figure 1). Post-hoc pairwise comparisons showed that ATF load rate was significantly lower in the medial orthosis in relation to the lateral and no-orthotic condition.

No-orthosis Medial Lateral
Mean SD 95% CI Mean SD 95% CI Mean SD 95% CI
Maximum ATF (N/kg) 53.90 8.23 48.67-59.13 49.96 9.37 44.01-55.91 54.32 9.56 48.25-60.39
ATF rate (N/kg/s) 431.30 126.84 350.71-511.89 400.25 130.53 321.32-487.19 444.11 139.85 355.25-532.97
ATF impulse (N/kg·s) 5.84 1.21 5.08-6.61 5.61 1.20 4.85-6.37 5.89 1.46 4.96-6.82

Table 1 Achilles tendon kinetics (Mean, SD and 95% CI) as a function of the different orthotic conditions.

Figure 1 Achilles tendon force during the stance phase (black = lateral, dash = medial, grey = no-orthosis).

Discussion

The aim of the current investigation was to determine the effects of medial and lateral foot orthoses on AT kinematics. To the author’s knowledge, this represents the first investigation to examine the biomechanical effects of medial and lateral orthoses on AT kinetics. This investigation provides evidence of potential positive effects on running kinematics of orthoses, focusing on AT load. Results of this study could potentially be used in the treatment of AT pathologies or in the development of more effective orthoses.

The first key observation from the current investigation is that medial orthosis produced significantly lower ATF load rate and peak ATF. Findings from this investigation support the proposition of Donoghue et al., [12] who proposed that a high medial foot arch can contribute to the reduction of loads experienced by the AT during running and that orthoses can reduce the symptoms of chronic injuries of the AT as a result of cyclical loading; potentially explaining a component of the load reduction identified when using medial orthoses. Lersch et al., [9] proposed that manipulation of the calcaneus position affected the force distribution of the triceps surae and therefore the AT; given that the insertion points of the medial/ lateral gastrocnemius and soleus muscles increased calcaneal range of motion; this would therefore increase the tensile forces on the AT. This is supported by the OpenSim model for muscle tendon units proposed by Delp et al., [20]. The findings of this investigation would support this proposal due to the effect a medial orthosis has on calcaneus position. Excessive loading of the AT is considered to be a key mechanism linked to the aetiology of AT pathologies in runners [21] as decomposition of the collagen fibers that comprise the structure of the AT exceeds fiber synthesis. Therefore, the key implication of these from this observation is that medial orthoses when compared to lateral and no orthoses; reduce the kinetic parameters linked with the aetiology of AT pathologies.

Lateral orthoses are heavily utilized for the treatment of medial tibiofemoral compartment pathologies [22]. Laterally wedged orthotic devices have been shown to reduce the knee adduction moment which is a measurement of compressive medial knee compartment loading [22, 23]. However, the findings of this investigation indicate that lateral orthoses should perhaps be utilized contextually in that they could potentially increase the likelihood of the development of AT injuries.

Excessive lateral manipulation of the calcaneus could result in restriction of the blood supply to the AT which has been suggested as a cause of increased AT pathologies [24]. Therefore, it can be speculated that medial orthoses may be able to attenuate the risk of development of AT pathologies in runners, although further prospective work is required to fully establish this. It should be noted that this finding was observed when performing fully anticipated and controlled movements in a laboratory setting, therefore the results may not be generalizable to a running specific environment where variables are not controlled to the same level.

In conclusion, the current knowledge with regards to the efficacy of medial/lateral orthoses during locomotion is limited; therefore, the current investigation addresses this by examining the effect AT kinetics during running movements. The current study showed firstly that AT kinetics are significantly affected by the orientation of the orthoses used; with the lateral and no-orthotic conditions presenting significantly increased peak ATF, ATF load rate and AT impulse. Therefore, the current investigation indicates that that medial orthoses significantly attenuated AT loading parameters linked to the aetiology of AT pathologies, although further study is required to determine whether reductions in AT load as a function of medial orthoses serve to attenuate the risk of developing AT pathologies as a result of running.

References

  1. Kannus, P. (2000). Structure of the tendon connective tissue. Scandinavian journal of medicine & science in sports, 10(6), 312-320.
  2. Doral, M. N., Alam, M., Bozkurt, M., Turhan, E., Atay, O. A., Dönmez, G., & Maffulli, N. (2010). Functional anatomy of the Achilles tendon. Knee Surgery, Sports Traumatology, Arthroscopy, 18(5), 638-643.
  3. O’Brien, M. (2005). The anatomy of the Achilles tendon. Foot and ankle clinics, 10(2), 225-238.
  4. Sinclair, J. (2016). Effects of a 10 week footstrike transition in habitual rearfoot runners with patellofemoral pain.  Comparative Exercise Physiology. 12(3), 141-150
  5. Willy, R. W., Halsey, L., Hayek, A., Johnson, H., & Willson, J. D. (2016). Patellofemoral joint and Achilles tendon loads during overground and treadmill running. Journal of Orthopaedic & Sports Physical Therapy, (0), 1-31.
  6. Wulf, M., Wearing, S. C., Hooper, S. L., Bartold, S., Reed, L., & Brauner, T. (2016). The Effect of an In-shoe Orthotic Heel Lift on Loading of the Achilles Tendon During Shod Walking. journal of orthopaedic & sports physical therapy, 46(2), 79-86.
  7. Le Bocq, C., Rousseaux, M., Buisset, N., Daveluy, W., Blond, S., & Allart, E. (2016). Effects of tibial nerve neurotomy on posture and gait in stroke patients: A focus on patient-perceived benefits in daily life. Journal of the Neurological Sciences, 366, 158-163.
  8. Lorimer, A. V., & Hume, P. A. (2014). Achilles tendon injury risk factors associated with running. Sports Medicine, 44(10), 1459-1472.
  9. Lersch, C., Grötsch, A., Segesser, B., Koebke, J., Brüggemann, G. P., & Potthast, W. (2012). Influence of calcaneus angle and muscle forces on strain distribution in the human Achilles tendon. Clinical biomechanics, 27(9), 955-961.
  10. Hockings, M., & Nester, C. (2000). Use of dorsal ankle orthoses in the management of Achilles tendon rupture. The Foot, 10(1), 51-54.
  11. Fröberg, Å., Komi, P., Ishikawa, M., Movin, T., & Arndt, A. (2009). Force in the achilles tendon during walking with ankle foot orthosis. The American journal of sports medicine, 37(6), 1200-1207.
  12. Donoghue, O. A., Harrison, A. J., Laxton, P., & Jones, R. K. (2008). Orthotic control of rear foot and lower limb motion during running in participants with chronic Achilles tendon injury. Sports Biomechanics, 7(2), 194-205.
  13. Sinclair, J., Hobbs, S. J., Taylor, P. J., Currigan, G., & Greenhalgh, A. (2014). The influence of different force and pressure measuring transducers on lower extremity kinematics measured during running. Journal of applied Biomechanics, 30(1), 166-172.
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  15. Graydon, R. W., Fewtrell, D. J., Atkins, S., & Sinclair, J. K. (2015). The test-retest reliability of different ankle joint center location techniques. Foot and Ankle Online Journal, 1(11), 13-20.
  16. Sinclair, J., Hebron, J., & Taylor, P.J. (2015). The test-retest reliability of knee joint center location techniques. Journal of Applied Biomechanics, 31(2), 117-121.
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The D-Foot, for prosthetists and orthotists, a new eHealth tool useful in useful in risk classification and foot assessment in diabetes

by Ulla Hellstrand Tang BSc1,2*, Roy Tranberg PhD1, Roland Zügner BSc1, Jon Karlsson MD PhD1, Vera Lisovskaja PhD3, Jacqueline Siegenthaler BSc2, Kerstin Hagberg PhD1,2

The Foot and Ankle Online Journal 10 (2): 4

Background: The prevention and care of foot problems in diabetes begins with a risk classification. Today, the prosthetists and orthotists (CPO) and other health care professionals assess the risk of developing foot ulcers more or less subjectively. The objective of the study was to describe the construction of an eHealth tool, the D-Foot, which generates a risk classification. The reliability of the D-Foot was tested.
Methods: The D-Foot includes 22 clinical assessments and four self-reported questions. The content validity was assured by expert group consensus and the reliability was assessed through an empirical test-retest study. Inter- and intra-rater reliability was calculated using patients referred to four departments of prosthetics and orthotics (DPO).
Results: The agreement for the risk classification generated using the D-Foot was 0.82 (pooled kappa 0.31, varying from 0.16 to 1.00 at single DPOs). The inter-rater agreement was > 0.80 regarding the assessments of amputation, Charcot deformity, foot ulcer, gait deviation, hallux valgus/hallux varus and risk grade. The inter- and intra-rater agreements for the discrete measurements were > 0.59 and > 0.72 respectively. For continuous measurements, the inter- and intra-rater correlation varied (0.33-0.98 and 0.25-0.99 respectively).
Conclusion: The D-Foot gave a reliable risk foot classification. However, there was a variation in the inter- and intra-rater reliability of the assessments included and refinements are needed for variables with low agreement. Based on the results, the D-Foot will be revised before it is implemented in clinical practice.

Keywords: diabetic foot, screening, risk factor, eHealth, orthotics, diabetic foot ulcer, foot deformity, neuropathy, plantar pressure

ISSN 1941-6806
doi: 10.3827/faoj.2017.1002.0004

1 – Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
2 – Department of Prosthetics and Orthotics, Sahlgrenska University Hospital, Gothenburg, Sweden
3 -Department of Mathematical Science/Mathematical Statistics, Chalmers University of Technology and University of Gothenburg, Sweden
* – Corresponding author: ulla.tang@vgregion.se


Risk classification as a result of a structured foot assessment is a prerequisite to prevent the development of diabetic foot ulcers (DFU) [1-4]. An accurate risk assessment is crucial for effective DFU prevention, as well as for promoting good foot health, in order to enhance quality of life and reduce health-care costs [5, 6]. The interventions for patients running an increased risk of diabetic foot ulcers is podiatry, assistive devices (insoles, shoes), regular checks, education and multidisciplinary service [1, 3, 7].

The results from a recent survey performed in the Nordic countries shown an urgent need for improvement of the risk classification systems to be used in the clinic. The survey included 601 responses from hospitals and foot clinics in the Nordic countries and questioned whether guidelines in diabetes care were implemented in everyday clinical practice [8]. The results showed that 24% answered they did not routinely examine the patients’ feet (144/601) and that 61% did not use the current guidelines in their prevention and care of foot problems in diabetic patients. The need for an improved assessment routine is therefore obvious and immediate. However, it should be noted that national and regional differences exist in terms of the need is for improvement of the risk classification systems that are used in the clinics. Information from the Swedish Board of Health and Welfare show large regional differences regarding the number of amputations in patients with diabetes in different parts of the country [9], ranging from 180 – 395 persons per 100,000 patients with diabetes (age-specific values for first-time amputees per 100,000 patients with diabetes in 2008-2012 for patients > 40 years old and under medical treatment for diabetes.) These numbers, considered as quality indicators, put a demand on politicians and decision-makers to offer health care givers valid and reliable methods to assess the foot ulcer risk. Moreover, it has been reported that 76% of the patients registered in the Swedish National Diabetes Register in 2013 were classified as risk group 1, indicating no risk of developing foot ulcers [10]. This implies that the majority of patients with diabetes have no risk factors. This number contrasts with an expected prevalence of 50-67% of diabetic patients having neuropathy and they should consequently be classified as risk group 2 or more [1, 11, 12].

The responsibility for the prevention and/or treatment of diabetic foot complications rests with all medical staff and should preferably begin with a regular foot assessment performed in primary care or at the medicine clinics at the hospitals [1]. The presence of an acute DFU should lead to rapid action with a referral to the multidisciplinary team [1, 3]. Moreover, when a health-care provider identifies a patient with an increased risk of developing DFU, a referral to a department of prosthetics and orthotics (DPO) and to podiatry is strongly recommended [1]. At the DPO, a certified prosthetist and orthotist (CPO) is responsible for classifying the risk of DFU based on a foot assessment. The CPO then provides the patient with optimised footwear, insoles, orthoses or prostheses. To determine “optimised” treatment, factors such as a) the aim of the device, b) the general recommendations regarding DFU prevention and treatment and c) the patient’s preferences need to be considered. The prescription of assistive devices in Sweden (including insoles/shoes) is regulated by national law and regional recommendations [1, 13-17]. The current study was initiated because a) many referrals to the DPO did not include the patient’s risk stratification and b) as a reaction to the current lack of any structured assessment tool to be used by CPOs in Sweden.

The purposes of the study were to:
a) describe the construction of an eHealth tool for risk classification and foot assessment in diabetes and
b) assess the inter- and intra-rater reliability of the tool.

Methods

The D-Foot, an eHealth tool [18] for risk classification and foot assessment in diabetes, primarily intended for CPOs, was developed and tested during 2011-2015. A multicentre expert group in the Västra Götaland Region (VGR), consisting of CPOs, pedorthists, physiotherapists and orthopaedic surgeons, was created. A leader (UT) was designated to manage the project at four DPOs. Collaboration with diabetes patient associations was established. The software, called the D-Foot (vers. 2014.01), was programmed for tablets (Samsung Galaxy TAB 2 (10.1) and TAB 4 (10.0)). A manual was produced to assist the CPOs with the assessments, Figure 1.

Figure 1 Some examples of the instructions in the D-Foot eHealth tool.

Content validity

The content validity of the D-Foot was assured through continuous discussions and revisions in combination with a systematic literature review [19-21]. The algorithm giving the risk classification (1-4) followed regional guidelines (Figure 2). The risk classification corresponds to the classification in the Swedish National Diabetes Register [1, 22]. Some variables (self-perceived pain; inappropriate footwear; insufficient function of the toes and metatarsophalangeal joints, gait deviation affected from hip/knee, foot length and foot width) not identified as risk factors in the regional guidelines, were also included, as they were found to be clinically relevant and of interest in future research. The criteria for the D-Foot were a) to include the most important risk factors for DFU and b) that the assessment procedures should be easy to learn and quick to perform.

Figure 2 Risk classification 1-4, symptoms and recommended treatment displayed in the D-Foot eHealth tool.

For the measurement of foot length and width, a calliper was used (Brunngård, Borås, art # 500210) and maximum toe height and navicular drop were measured using a ruler. The validity when measuring foot length using a calliper has previously been found to be high [23]. A new method for measuring maximum toe height in a weight-bearing position, using a ruler, was introduced (Figure 1). A plastic goniometer (full length 36 cm) was used to measure the ankle angle and metatarsophalangeal joint dorsiflexion. The techniques used to measure foot width, foot length and maximum ankle dorsiflexion angle have been described previously in detail [10]. Measurements of peripheral angiopathy was not included in the first version of the D-Foot.

Reliability

The reliability of the D-Foot was assessed by two CPOs at each of four DPOs. Inter-rater reliability was tested by comparing the results of the foot assessments made by two different observers on the same day. All patients were initially examined by the first CPO, called “Observer 1”, using the D-Foot web program, followed by an independent examination by Observer 2 on the same occasion. Each observer used his/her own tablet throughout the study. Intra-rater reliability was assessed by comparing the results obtained by the same observer on two different occasions (the second appointment approximately two weeks after the first) [24]. A two-week interval was chosen, as it was judged to be short enough to ensure stable foot status but long enough to ensure that the observer would be free from memory bias [25].

Prior to the study start, all eight observers (two observers at each DPO) were instructed on how to examine the feet using the D-Foot. The practical instructions followed a structured protocol and the observers tested using the web-based software on a tablet. After study completion, all the observers were asked to answer the System Usability Scale (SUS) [26]. The SUS is a survey used to collect ten subjective answers about how users rate the use of an interactive technology (Table 4). To compare the risk classification made by the referring health-care provider with the risk classification generated by the D-Foot, an additional analysis of agreement was made between the two.

Patients

Informed consent was obtained from the patients who agreed to participate and met the following inclusion criteria: being diagnosed with diabetes, having the ability to read and understand written instructions in Swedish, age ≥ 18 and referred to the DPO for the provision of assistive devices to prevent and treat diabetic foot complications. All the patients answered a survey on a tablet, including questions on height, weight, duration and type of diabetes, use of nicotine products and medication for treating high blood pressure or cardiac diseases. The patients also estimated whether they a) had the ability to walk normally, b) had good balance and c) perceived that they had normal sensations in their feet. In addition, the use of walking aids was reported. Ethical approval was given by the Gothenburg Regional Ethical Board (Dnr 1041-13).

Statistical analysis

The D-Foot comprises 16 discrete measurements (e.g. amputation yes/no) and six continuous measurements (e.g. foot width). For the discrete measurements, inter- and intra-rater reliability was analysed with an estimate of the proportion of patients on whom the observers agreed [27, 28]. A value of 1.00, complete inter-rater agreement means that the two observers registered measurements such as hallux valgus as being the same for all patients in the study. Using the assumption of independent and identically distributed observations, a confidence interval (CI) for this probability was constructed (p < 0.05, two-sided, Bernoulli distribution assumption). Poor reliability is present if the agreement is close to 0 while values close to 1 represent excellent reliability and values close to 0.5 reflect moderate reliability [24].

Cohen’s kappa analyses the “additional” agreement that was observed compared with the agreement that would be expected due to pure chance [29]. It has been suggested that a kappa value between 0.41-0.60 shows moderate strength of agreement, 0.61-0.80 (substantial) and 0.81-1.00 (almost perfect) [30]. First, a calculation of the kappa of each of the DPOs was made and, second, the obtained values were combined into an estimated pooled value, with the weights reflecting the number of patients at each DPO. When the distribution is zero (only one alternative is chosen) at a single DPO, the kappa value was set to 1 (e.g. observer 1 classified the patients foot as “no foot ulcer” and observer 2 did the same.

For the continuous variables, the mean (± SD) and mean difference (± SD) between observations were calculated. A variation of Pearson’s correlation coefficient and the intra-class correlation coefficient (ICC) were used, beginning with a calculation of Pearson’s correlation coefficient and the ICC of each of the DPOs and the obtained values were then combined into an estimated pooled value, with the weights reflecting the number of patients at each DPO [28]. Finally, Student’s t-test and the chi-square test (p < 0.05) were used to analyse whether age and gender were similar between the groups of included patients compared with those who refrained from participating in the study. The results for the right foot are presented, as the exploratory analysis revealed that there was dependence between the feet.

The SUS score was calculated per person and per question respectively [31]. Each question could be answered with a score (strongly disagree = 1 to strongly agree = 5). First, from the responses with an odd number, “one” was subtracted. Second, from the responses with an even number, subtract their value from “five”. The value obtained for each question and person ranged from 0-4, with four as the highest response. By multiplying the sum of the converted responses by 2.5, a score for all 10 questions, ranging from 0-100, was obtained. By multiplying the total score for each question by 3.125, a score ranging from 0-100 was obtained for the eight observers. The mean and SD for the total scores were then calculated.

Results

Table 1 (see attached supplement) presents the D-Foot tool including four patient-reported questions, 16 discrete foot assessments and six continuous foot assessments. In the same table, the risk category for each assessment, e.g. neuropathy, foot deformity, skin pathology and anamneses is presented, together with a brief description of the reason for each assessment being included and with references to existing evidence in the literature. Finally, in the last column, the expert group states the improvements made to the D-Foot version 2. Examples of assessments included in the D-Foot are presented in Figure 1.

The study population consisted of 102 patients at four sites: DPOA-DPOD. No statistical difference was observed, regarding gender, between the 13 women and 13 men who declined participation compared with those who agreed, 42 women and 55 men, p = 0.434. The estimated mean age of those who declined participation was 66 ± 16 years vs. 64 ± 13 years for the included participants, p = 0.187.

After excluding incomplete assessments (n = 5 inter-rater tests, n = 20 intra-rater tests), the data set consisted of 97 inter-rater measurements (DPOA (n = 38), DPOB (n = 14), DPOC (n = 23) and DPOD (n = 22)) and 82 intra-rater measurements. The inter-rater measurement patient group consisted of 33 patients with diabetes type 1 and 64 patients with type 2. The mean duration of diabetes was 17 ± 14 years, the HbA1c was 60 ± 15 mol/mmol (6.7 ± 1.5%) and the BMI was 28 ± 5. The survey revealed that 26 (27%) used nicotine products (15 cigarettes, 11 snuff), 74 (76%) were taking medicine to treat high blood pressure and 31 (32%) were being treated for cardiac diseases. Moreover, 62 (64%) reported that they walked normally and experienced good balance, 20 (21%) used a walking aid and 54 (56%) reported having normal foot sensation. Seventy-five (77%) of the patients had signs of neuropathy when assessed by Observer 1 at the first examination (having tingling/numbness, less sweaty feet and/or a positive Ipswich Touch Test). The time interval between the first and the second assessment was 20 ± 11 days.

In Table 2, the inter- and intra-rater agreement for the discrete variables for the right foot is presented, as well as the prevalence of each risk factor, as assessed by Observer 1 at the first appointment. An inter-rater agreement of > 0.80 was found for the risk factors: presence of amputation, Charcot deformity, foot ulcer, gait deviation, hallux valgus/hallux varus and risk grade. The intra-rater agreement revealed that 13 measurements had a pooled kappa of > 0.50 and four inter-rater measurements had a kappa of > 0.50. The sub-analysis revealed that the kappa value differed between sites (inter-rater kappa < 0.05 at a single DPO), i.e. with regard to insufficient function in the toes and metatarsal phalangeal joints.

The agreements for the continuous variables are presented in Table 3, exemplified with a scatter plot of maximum dorsal flexion at the hallux joint, Figure 3. The scatter plot revealed site-dependent differences, indicating systematically lower values at different sites, e.g. DPOB and DPOD measured maximum dorsal flexion at the metatarsophalangeal joint as smaller (20-50 degrees) compared with DPOA and DPOC (50-150 degrees).

Figure 3 Inter-rater agreement in the assessment of passive range of dorsiflexion at metatarsophalangeal joint 1. Scatter plots visualizing the variation in inter-rater agreement at the four departments of prosthetics and orthotics (DPO). DPOA: red triangle; DPOB: black circle; DPOC: green plus sign; DPOD: blue cross.

Forty-one of the 97 referrals (42%) to a DPO included a risk classification made by a medical doctor. The agreement (± CI width) between their risk classification and the risk classification generated by the D-Foot was 0.41 ± 0.11 and Cohen’s kappa was 0.06.

All eight observers answered the SUS and scored the 10 questions with regard to the usability of the D-Foot as 70 ± 16 (45-95), Table 4. An SUS score (78) for a separate question was: “I would imagine that most people would learn to use this system very quickly” and “I found the system very cumbersome to use”. An SUS score (75) was “I thought the system was easy to use” and “I found that the various functions in this system were well integrated”. The question “I think that I would need the support of a technical person to be able to use this system“ had an SUS score of 84.

Discussion

The most important issue in the current study is the presentation of a novel eHealth tool, the D-Foot aimed to be used by CPOs. The results of the current study show a high level of agreement for the risk classification (inter-agreement 0.83, pooled kappa 0.31, varying from 0.16 to 1.00 at single departments), (Table 2). The corresponding intra-rater agreement was 0.88 (pooled kappa 0.63, varying from 0.42 to 1.00) at single departments. A high degree of inter- and intra-rater reliability was found for the presence of Charcot foot deformity and amputation (agreement of > 0.90, kappa > 0.73) [30]. These risk factors are easy to detect by visual inspection. The agreement between the observers was adequate when it came to the Ipswich Touch Test and hallux valgus/varus, all of which showed an agreement between 0.79-0.86 and a kappa of > 0.56. As expected, the intra-rater agreement was generally higher than the inter-rater agreement.

Measurements of foot length and width (Table 3) using a foot calliper were shown to be highly reliable (pooled correlation > 0.92) [32]. The low agreement when measuring toe height and navicular drop test (pooled correlation < 0.33; pooled ICC < 0.32) led to a decision to exclude the navicular drop test in the next version of the D-Foot. Moreover, the navicular drop test was found to be a time-consuming assessment.

The scatter plot (Figure 3) revealed site-dependent differences when measuring the passive motion of the big toe. For this measurement, the correct body position (hip, knee and foot joint) is important, as it affects the hallux dorsiflexion. Moreover, several registered values relating to the big toe and ankle joint motion were found to be extreme and were excluded in the analysis. One explanation for these extreme values might be uncertainty among clinicians about how to use and read a goniometer.

In some patients, the time interval between the assessments was longer (20 days) compared with the recommended 14-day interval. This was due to personal reasons or technical problems at the DPO. With a prolonged interval, there is a greater possibility that the foot status will change, thus reducing the level of intra-rater agreement. The results of the study emphasise the importance of using a structured clinical assessment and underline the challenge involved in making a reliable foot assessment, even though a structured tool and a manual are available [24].

The D-Foot captures essential risk factors that need to be assessed, i.e. neuropathy, foot deformities, skin pathologies, history of ulcers/amputation, ongoing foot ulcers and osteoarthropathy (Charcot deformity) [1, 3]. To capture and identify the risk factor of “foot deformities”, several assessments (Charcot deformity, maximum toe height, hallux valgus/varus, calcaneus valgus/varus, abduction/adduction of the forefoot, dorsiflexion at the metatarsal joint, dorsiflexion at the ankle joint, prominent superficial bony structures in the plantar area, navicular drop test, gait deviation and insufficient function of the toes and metatarsal phalangeal joints) were included. Moreover, areas with excessive pressure on the foot and inspection of the alignment of the shoes were included in the D-Foot. Several of these risk factors have been found to be related to high peak pressure, thereby contributing to an increased risk of developing pressure-induced foot ulcers [33].

A new measurement of maximum toe height, as a sign of hammer toe deformity, was introduced. The accuracy of assessing biomechanical abnormalities, such as hammer toe deformity, by visual inspection and clinical assessments has been reported to be limited [34, 35]. In the current study we introduced a quantitative measure of hammer toe deformity “the measure of maximum toe height”. By using this new method a ruler was used and the assessment was demonstrated in Figure 1. The measurement error, of toe height measurement using a ruler, has been reported to be good (± 0.18 mm) [36]. A hammer toe height exceeding 25 mm was set as the threshold value. The relevance of setting 25 mm as a threshold was based on commonly used toe-box heights of 22-26 mm for off-the-shelf shoes (for adults) [36, 37].

Among the included assessments, the Ipswich Touch Test [38] and measuring foot length [23] have previously been tested for validity and/or reliability, with good results. However, the present study shows that there is a need to validate the remaining assessments.

Neuropathy, one important risk factor, was registered as being present in 77% of the patients. Neuropathy was considered to be present if any of the following three tests/questions produced a positive result: 1) numbing/tingling sensation in the feet, 2) less sweaty feet nowadays compared with recent years and 3) a positive Ipswich Touch Test [38, 39]. That is, peripheral neuropathy was assessed in three ways. Moreover, the Ipswich Touch test was by the consensus group regarded as a better test to be performed by health-providers at department of prosthetics and orthotics than the monofilament. Less sweaty feet, one cause of dry skin, was included as a sign of autonomic neuropathy [40]. The prevalence of neuropathy in the present study is similar to the prevalence of 67% reported by Kärvestedt et al. [12]. It is noteworthy that 56% of the patients, as shown in the self-report questions, perceived that they had normal sensitivity in their feet, indicating that some patients are not aware of the neuropathy. The reasons to include questions whether the patients perceived that they had ‘normal sensation’ and ‘walked normally’ were to describe in-depth the cohort of patients.

Improvements to D-Foot

Based on the current results, the main improvements to the next version of D-Foot will be: 1) to add a test of peripheral angiopathy, 2) to exclude the navicular drop test, the assessment of areas of excessive pressure with callosities, the assessment of insufficient function in the metatarsal joints/toes and the assessment of gait deviation. Finally clarifications of the instructions will be made.

In the next version, both acute Charcot foot and manifest Charcot foot will be assessed (Table 1), based on the fact that the presence of acute Charcot foot leads to risk grade 4 and manifest Charcot foot leads to risk grade 3. Moreover, a validation of the input data will be made in the D-Foot version 2 with the aim of increasing the quality of the data. An example of the programmed help text: when a value of (e.g. toe height > 44 mm) is registered, the CPO will read the following help text on the display: “is the value of 40 mm correct?”

Limitations

The lack of measurements of peripheral angiopathy in the current version of the D-Foot is a weakness that has been thoroughly discussed in the expert group. Even if the palpation of foot pulses is not a robust method an addition of this test will improve the risk classification [41, 42]. There are limitations to the kappa statistic appearing when the result is unbalanced (the observers are likely to choose one of the alternatives). This leads to a low kappa value, even though the agreement is high [29, 43]. In these cases, it is more informative to consider the kappa value for each separate DPO in combination with the information obtained from the percentage of agreements. A kappa value below zero means that the agreement is less than what can be expected due to chance. The expert group thought that this occurred in single assessments because the description of the assessment was unclear and was therefore misinterpreted by the observers. As described, two techniques were used to reflect the level of reliability among the discrete variables. However, the percentage of agreement has the limitation that it does not consider the possibility that the agreement was made by chance and the limitations in the kappa statistics have been stated above.

Risk stratification

A variety of foot assessment forms and routines have been developed. None of them, to the best of our knowledge, has been tested for reliability [1, 21, 44-49]. The fact that health care professionals use methods that are more or less tested for validity/reliability in foot screening procedures has previously been demonstrated by Formosa et al. [49]. These authors made a literature review that evaluated current guidelines for foot screening in diabetes. The authors found a great variability in terms of the evidence-based methods used to achieve the set targets. These authors concluded that more attention should be paid to the limitations in current guidelines, the underlying evidence and the recommendations for everyday clinical practice [49].

In current study, poor agreement (0.41) and a low kappa (0.06) were found when comparing the risk classification made by the referring health-care providers and the D-Foot classification. The mismatch indicates that health-care providers need guidance to identify the “true” objective, risk grades 1-4. Using digital tools, such as the D-Foot, a more objective and consistent assessment of the risk level can be made [21, 47]. With modifications, such as adding assessments of peripheral angiopathy and excluding some of the tests identifying foot deformities, the D-Foot will hopefully be useful as a decision support for health-care providers other than CPOs. The reason for excluding measurements of peripheral angiopathy in the current version of the D-Foot was that the CPOs, in general, are unskilled in performing these assessments. Moreover, the validity and reliability when palpating foot pulses have been shown to be weak [41, 42].

Usability

Using a tablet was a new experience for all eight observers. In their ratings of the usability of the D-Foot, there was some variation (45-95), indicating that some users found the D-Foot less useful and some found it excellent [26]. The observers had a strong belief that they would need technical support when using the D-Foot in clinical practice. When introducing the D-Foot in clinical practice, an introductory course designed to explain the basics of the D-Foot, thereby facilitating its use, should be available. Naturally, there was a great deal of variety in the observers’ opinions when it came to their thoughts about using the D-Foot frequently.

The D-Foot software generates a complete report, including all foot assessments and the risk classification. This report should preferably be automatically linked to the medical record system to save time, improve the quality of documentation and simplify and enhance treatment evaluation.

Several patients made positive comments when their feet were assessed using the D-Foot program. The risk level classification, displayed during the session, and the illustrative interface inspired a motivational discussion in terms of the patients’ self-care, the need for podiatry and footwear.

Clinical relevance

Patients at risk of developing diabetic foot ulcers are more likely to be identified if health-care professionals use structured routines [20, 21]. The D-Foot was constructed to provide a consistent examination of the feet. A revised D-Foot would give a reliable risk classification, with the aim of reducing the risk of developing diabetic foot ulcers. The plan is to implement and evaluate the D-Foot in clinical practice during 2017. The evaluation will examine: a) patients’ opinion of how they experience being examined using the D-Foot, b) the CPOs’ opinion of what it is like to use the D-Foot in clinical practice and c) how meta-data generated by the D-Foot can be used in the prevention and care provided by the DPO. Continuous improvements to the D-Foot are planned, based on structured evaluations of the experience of patients and personnel when the D-Foot is implemented and used in clinical practice.

Conclusion

The level of agreement for risk classification, ulcers, amputations and Charcot deformity was high. There was variation in the inter- and intra-rater reliability. After revision, the D-Foot is recommended for use in daily practice at DPOs and by other health-care providers. An international spread is possible, with translation and adaptation to national recommendations in other countries.

Declarations

Abbreviations

DFU; diabetic foot ulcers, DPO; department of prosthetics and orthotics, CPO; certified prosthetist and orthotist, VGR; Västra Götaland Region, CI; confidence interval, ICC; intraclass correlation coefficient

Acknowledgements

We would like to thank all the patients for their contribution to the study, together with all the co-workers at the DPO Sahlgrenska University Hospital, Gothenburg, the DPO Södra Älvsborgs Sjukhus, Borås, the DPO NU-sjukvården, Trollhättan/Uddevalla, and the DPO Skaraborgs Ortopedservice AB, Skövde, all situated in the Västra Götaland Region in Sweden. Finally, we would like to thank our graphic designer, Pontus Andersson, and web programmer, Christoffer Thomeé.

Funding

This research was supported 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 and the Gothenburg Diabetes Association, Greta och Einar Askers Stiftelse, Hans Dahlbergs stiftelse för miljö och hälsa and Sveriges Ortopedingenjörers Förening.

Availability of data and material

The data sets supporting the conclusion of this article are included within the article.

Authors’ contribution

UT designed the study, researched the data, contributed to discussions and wrote the manuscript. RT, RZ, JK, VL, JS and KH designed the study, researched the data, contributed to discussions, reviewed and edited the manuscript.

Authors’ information

UT and JS are certified prosthetists and orthotists at the Department of Prosthetics and Orthotics, Sahlgrenska University Hospital. RT is a certified prosthetist and orthotist and RZ is a registered physiotherapist working at the Lundberg Laboratory for Orthopaedic Research, at Sahlgrenska University Hospital. JK is chief physician at the Department of Orthopaedics, Sahlgrenska University Hospital, and Professor at the Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University. VL has a PhD in mathematical statistics from the Department of Mathematical Science/Mathematical Statistics, Chalmers University of Technology and University of Gothenburg, Sweden. KH is a registered physiotherapist at the department of Prosthetics and Orthotics, Sahlgrenska University Hospital, and Associate Professor at the Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University. They are all based in Gothenburg, Sweden.​

Competing interest

The authors declare that they have no competing interests.

Ethical approval and consent to participate

Ethical approval was given by the Gothenburg Regional Ethical Board (Dnr 1041-13). Patients were informed of the study design before they provided written consent.

Consent for publication

Not applicable

TABLES SUPPLEMENT

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Trigger events for Charcot neuroarthropathy: A retrospective review

by Brent H. Bernstein DPM  FACFAS1, Payel Ghosh DPM2, Colleen Law DPM3, Danielle Seiler DPM4, Thuyhien Vu DPM5

The Foot and Ankle Online Journal 10 (2): 3

Charcot arthropathy is a rare, but devastating disease process that has significantly debilitating sequelae. While several theories have been discussed within the literature regarding the causative factors, there remains much debate to the exact pathogenesis. Nevertheless, recognition and timely treatment of this issue remains a paramount task for every healthcare provider. In order to accomplish this, we investigated specific trigger events that led to the onset of the Charcot, by subjectively interviewing patients.  Ultimately, we were able to identify acute trauma, surgical events, infections, and also overuse injuries all as inciting events to this disease process. The overall goal of this paper is to improve recognition of the possible triggers that leads to the Charcot disease process in order to better care for patients. 

Keywords: Charcot, diabetic foot, trigger event, neuropathy, neuroarthropathy

ISSN 1941-6806
doi: 10.3827/faoj.2017.1002.0003

1 – Attending, Research Coordinator, Podiatry Residency, St. Luke’s Hospital Allentown, PA
2 – Podiatric Resident, St. Luke’s Hospital Allentown, PA
3 – Podiatric Resident, St. Luke’s Hospital Allentown, PA
4 – Associate at Premier Foot & Ankle Associates Wyomissing, PA
5 – Teaching Staff, Mercy Medical Center, Cambodia
* – Corresponding author: ghosh.payel@gmail.com


Charcot neuroarthropathy is a progressive and destructive process that can lead to debilitating sequelae such as ulcerations, foot deformity, fracture, dislocations, and even amputation [1]. Charcot has been associated with a number of different conditions; however, today diabetes mellitus is found to be the primary cause [2]. The epidemiological data shows that the prevalence of Charcot arthropathy in diabetic patients ranges from 0.08% to 13% while the incidence varies between 0.10% and 29% [1]. This wide difference in incidence within the literature is linked to higher index of suspicion from tertiary providers, such as wound care specialists.

The exact pathogenesis of Charcot remains ill defined.  The neurotraumatic and neurovascular theories continue to be the fundamental teachings; however, it is likely that there are a combination of several mechanisms involved [3]. It is thought that autonomic neuropathy, creates a hyperemic response by means of arterio-venous shunting leading to bone resorption and osteopenia.  Furthermore, it is suggested that motor neuropathy causes muscle imbalances within the foot, which leads to repetitive microtrauma.  This alone, or in combination with a traumatic event begins the process of osseous destruction.  Sensory neuropathy prevents the patient from recognizing this microtrauma, thus propagating the Charcot process [4].   Newer relate the pathogenesis to the disruption in the Charcot patient’s ability to regulate inflammation.  This results in increased levels of proinflammatory cytokines, such as tumor necrosis factor alpha (TNFα) and interleukin-1β (IL-1β) and a decrease of anti-inflammatory factors interleukin-4 and interleukin-10.  Increased TNFα leads to a cytokine cascade that eventually results in the activation of NF-κB, which causes osteoclast precursor cells to become mature osteoclasts.  This process causes excessive bone turnover due to increased osteoclast activity, thus resulting in the Charcot process [5].

To our knowledge, there have been no published reports aimed specifically at the initial inciting event that triggers the acute Charcot cascade. The purpose of this study was to analyze the trigger events leading to the development of Charcot neuroarthropathy with the hope that this information will give rise to preventative measures for these at risk patients.   

Methods

Data were obtained from the medical records of patients being treated by the primary author (BHB) with a diagnosis of Charcot neuroarthropathy between 2003 and 2010.  The diagnosis of Charcot was based on clinical presentation and radiographic evidence, including advanced imaging studies.  Swelling, erythema, warmth, pain, and a temperature gradient of four degrees Fahrenheit or more between the affected and contralateral limb were pertinent to the clinical diagnosis.  The clinical diagnosis was then confirmed with MRI or triple phase bone scan.

A total of 211 feet from the records were identified with Charcot; however, only 179 had complete data available. The triggering event was identified through patient interview and clinical examination.  Questions regarding prior trauma, surgery, infection, or overuse were discussed in detail in order to help determine the inciting event.  In 70 of the feet, a trigger could not be identified, and thus were excluded from the data analysis.  The triggering event preceding the acute onset of Charcot was analyzed and classified into five major categories.  The first category was acute injury, which included any single, identifiable event such as fractures or sprains that resulted in the onset of the Charcot process.  Diabetic ankle fractures were placed in their own separate category from the acute injury category due to their higher morbidity rate and more unique surgical protocol vs. a non-ankle fracture.  The surgical category consisted of patients who developed Charcot following recent non-elective or elective foot surgery.   The patients who had a recent of history of infection as an inciting event, but did not undergo any surgical procedures was placed into the infection category.  Lastly, the overuse category was for individuals who had an identifiable continued repetitive trauma from a particular event over a period of time.  Each foot was then classified based on Sander’s anatomic classification system as follows: Type 1=forefoot, Type II = tarso-metatarsal joint, Type III = naviculocuneiform and midtarsal joints, Type IV = ankle joint, Type V = calcaneus [1].  

The frequency of each trigger category as well as each anatomic location was analyzed.  For exploratory purposes only, given the small subgroup sizes, a chi square test of general association was conducted to compare trigger types by anatomic site.  A p-value < .05 denotes statistical significance.

Results

Complete data was available on 179 out of 211 feet.  A specific trigger event could not be identified in 70 feet and these were excluded from the data analysis; therefore, the final cohort included 109 feet.  Demographic information is summarized in Table 1.  The mean age was 55.97 years old ranging from 28 to 84.  There were 64 males and 45 females included in the study.  90% of our patient population was diabetic while the other 10% had neuropathy from other etiologies. Other etiologies did include, but were not limited to Alcoholic Neuropathy, Cauda Equina Syndrome, Agent Orange Syndrome, Idiopathic and Hypothyroidism. Of note, there were two cases of combined Diabetic and Syphilitic Neuropathy.

 

Age

(mean + standard deviation)

Gender Diagnosis
55.97 + 11.72(range 28 – 84) 64 male (58.7%)45 female (41.3%) Type II IDDM: 48 (44%)Type II NIDDM: 26 (23.9%)

Type I DM: 13 (11.09%)

DM Type unspecified: 11 (10%)

Idiopathic neuropathy: 2 (1.8%)

Syphilis/Type I DM: 2 (1.8%)

Alcohol/ETOH: 2 (1.8%)

Agent Orange poisoning: 1 (.9%)

Cauda Equina Syndrome: 1 (.9%)

Hypothyroid: 1 (.9%)

Type II IDDM/Agent Orange: 1 (.9%)

Non-diabetic: 1 (.9%)

Table 1 Demographic Characteristics (N=109)

Overall, the two most common trigger types identified were acute injury and overuse at 44% (48/109) and 18.3% (20/109) respectively as seen in Table 2.  These were followed by diabetic ankle fracture and foot surgery (17/109) for the third most common trigger at 15.6% (17/109).  Infection was the trigger event in 6.4% of the total feet (7/109).

 

Trigger Type Frequency (%)
Acute injury 48 (44%)
Overuse 20 (18.3%)
DM Ankle Fx 17 (15.6%)
Sx 17 (15.6%)
Infection 7 (6.4%)
TOTAL 109

Table 2 Trigger Category Percentages

After categorizing the inciting event into a classification of a trigger type, the data was analyzed to compare each event to its associated anatomic location. Acute Trauma was distributed affecting the forefoot 4.2% (2/48), the tarsometatarsal joint 45.8% (22/48), the midtarsal 22.9% (11/48), the ankle 18.8% (9/48) and the Calcaneus 8.3%  (4/48). Diabetic ankle fractures accounted for 17 cases and led to a midtarsal arthropathy 5.9% (1/17) and an ankle arthropathy 94.1% (16/17) of the time. Surgical intervention resulted in 17.6% (3/17) forefoot arthropathy, 41.2% (7/17) tarsometatarsal arthropathy, 23.5% (4/17) midtarsal arthropathy and 7.6% (3/17) ankle arthropathy.  Infection, which accounted for 7 cases of arthropathy, was observed 71.4% (5/7) at the tarsometatarsal level and 28.6% (2/7) at the level of the ankle joint. Overuse injury was observed to lead to arthropathy in 20 patients with 50% of those observed at the tarsometatarsal level (10/20), 45% (9/20) at the midtarsal level and 5% (1/20) at the level of the ankle joint.

Based on a chi square test of general association, there is a statistically significant association between trigger category and anatomic classification (p < .0001) in terms of the difference in frequencies (Table 3).

 

Anatomic Classification
I II III IV V
Trigger Category Acute Trauma Count 2 22 11 9 4
% within Trigger Category 4.2% 45.8% 22.9% 18.8% 8.3%
DM Ankle Fx Count 0 0 1 16 0
% within Trigger Category .0% .0% 5.9% 94.1% .0%
Sx Count 3 7 4 3 0
% within Trigger Category 17.6% 41.2% 23.5% 17.6% .0%
Infection Count 0 5 0 2 0
% within Trigger Category .0% 71.4% .0% 28.6% .0%
Overuse Count 0 10 9 1 0
% within Trigger Category .0% 50.0% 45.0% 5.0% .0%
Total Count 5 44 25 31 4
% within Trigger Category 4.6% 40.4% 22.9% 28.4% 3.7%

Table 3 Association Between Anatomic Site and Trigger Categories

Discussion

This study examines patients with Charcot neuroarthropathy and investigates the individual trigger events leading to the development of the disease process to further our insight as healthcare providers. The different trigger categories, as well as the anatomic classifications for each event were evaluated.  Our results indicate that the two most common triggers for developing acute Charcot were acute trauma and overuse.  Also, 40% of the total cases involved, developed Sanders type II Charcot.  Anatomic site II arthropathy was the most common form of Charcot that developed in all of the trigger categories, with the exception of a diabetic ankle fracture, which was the second most common and generated mainly type IV arthropathy.  This supports the general teaching that tarso-metatarsal joint Charcot arthropathy is traditionally the most common anatomic type that is observed [6]. In the process of investigating individual trigger events, the authors encountered patterns of inciting events, while no statistical significance could be drawn from these anecdotal incidences. One mechanism that was most closely associated with a Sanders type II arthropathy was the action of stepping on a ladder. This becomes important as a significant number of our patients work in a more industrial environment and are likely prone to an overuse or acute type injury of the tarsometatarsal complex. A similar mechanism that was demonstrated in a handful of patients was the actions of stepping down to a lower level or onto a curb.  Through these mechanisms was both Sanders II and Sanders IV type injuries were associated. Ultimately, while the collection of these events was not statistically significant, they have provided enlightenment to the providers and have affected the questions asked during intake today.

The results of this study were compared to current literature available where other researchers have attempted to understand the causes of Charcot neuroarthropathy. When looking further into the data it is interesting to note that 39% of the original 179 feet could not recall any precipitating event to their acute Charcot.  These patients were ultimately eliminated from data analysis for the purpose of this study.  This is in contrast to Armstrong et al where 73% of the subjects could not identify a single trigger event; however, it is possible that there is overlap between the overuse category and these patients.7 Furthermore, Papanas et al reported patients recalling a traumatic event in 36% of their patient population with a 12% association with surgical intervention [6]. Regardless, it is important to remember a singular trigger event may not always be identifiable and Charcot arthropathy should not be ruled out of the differential diagnosis subsequently.

In order to perform a comprehensive assessment of the diabetic foot, it is important to incorporate other considerations. Foltz et al evaluated both vascular and neurological findings in patients with Charcot foot deformity in order to identify high risk factors for development of a protocol for early detection in the non-hospital setting [8].   Additionally, Armstrong and Lavery analyzed peak plantar pressures of Charcot and non-Charcot feet to examine if this was a risk factor for or associated with the development of Charcot [7].  In conclusion, the authors felt that measuring these plantar pressures may be an effective addition to the screening protocol for these types of patients [9]. Rajbhandari et al proposed that pathognomonic factors for Charcot neuroarthropathy, likely involve a synthesis of competing classic theories [10]. It was believed that a substantial number of cases were likely triggered by a traumatic event, which also instigated an abnormal vascular reflex resulting in hyperemia to osseous components [11].

The limitations of this study includes the fact that it was a retrospective analysis.  Additionally, the report of each trigger event was subjective and dependent upon the insight from each patient.

We believe that the information from this study could be used in order to better educate our diabetic neuropathic patients on the topic of Charcot neuroarthropathy to aid in preventing its onset or to expedite treatment modalities with earlier recognition. Another important point for both clinicians to remember and for patient teaching purposes, is that the repetitive and overuse activities should not be overlooked as these can lead to a significant amount of neuroarthropathy. It is extremely important that all diabetic patients with peripheral neuropathy are properly educated on Charcot. The repercussions of a missed diagnosis given the expansive list of complications secondary to Charcot neuroarthropathy must be impressed upon high-risk patients. The intention of this paper was to display the different trigger categories and their frequencies so that this information could be used for prevention and educational purposes.

Funding Declaration The authors have no financial interests to disclose. Neither this research, nor its publication was funded.

Conflict of Interest Declaration The authors have no interests to declare.

References

  1. Frykberg RG, Belczyk R.  Epidemiology of the Charcot Foot.  Clinics in Podiatric Medicine and Surgery. 2008;25:17-28.
  2. Wukich DK, Sung W. Charcot Arthropathy of the Foot and Ankle: Modern Concepts and Management. Review. Journal of Diabetes and its Complications 2008: 1-18. (PubMed).
  3. Pinzur MS. Current Concepts Review: Charcot Arthropathy of the Foot and Ankle.  Foot Ankle International 2007;28:952-959. (PubMed).
  4. Van der Ven A, Chapman CB, Bowker JH.  Charcot Neuroarthropathy of the Foot and Ankle. Journal of the American Academy of Orthopedic Surgeons 2009;17: 562-571. (PubMed).
  5. Kaynak G, Birsel O, Guven MF, Ogut T. An Overview of the Charcot Foot Pathophysiology. Diabetic Foot and Ankle 2013; 4: 21117. (PubMed).
  6. Gouveri E, Papanas N. Charcot Osteoarthropathy in Diabetes: A Brief Review with an Emphasis on Clinical Practice. World Journal of Diabetes; 2011 May 15; 2 (5); 59-65.  (PubMed).
  7. 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;14:357-363.  (PubMed).
  8. Foltz KD, Fallat LM, Schwartz S. Usefulness of a Brief Assessment Battery for Early Detection of Charcot Foot Deformity in Patients with Diabetes. JFAS 2004;43:87-92. (PubMed).
  9. Armstrong DG, Lavery L. Elevated Peak Plantar Pressures in Patients who have Charcot Arthropathy. JBJS 1998;80A:365-369. (PubMed).
  10. Rajbandhari SM,  Jenkins RC, Davies C, Tesfaye S. Charcot Neuroarthropathy in Diabetes Mellitus. Diabetologia 2002; 45: 1085-1096. (PubMed).
  11. Petrova NL, Edmonds ME. Acute Charcot Neuro-Osteoarthropathy. Diabetes/ Metabolism Research and Reviews 2016; 32 (Suppl. 1): 281-286. (PubMed).

Radiographic changes in coronal alignment of the ankle joint immediately after primary total knee arthroplasty for varus knee osteoarthritis

by Ichiro Tonogai1*, Daisuke Hamada1, Koichi Sairyo1

The Foot and Ankle Online Journal 10 (2): 2

Objective: Total knee arthroplasty (TKA) is a common surgical procedure used to treat patients with high-grade varus knee osteoarthritis (OA). However, a change in alignment of the knee may cause radiographic problems in the ankle joint and secondary clinical complaints. The purpose of this study was to investigate radiographic changes in coronal alignment of the ankle joint immediately after primary TKA for varus knee OA.
Methods: In this study, 125 cases in 91 patients (30 case in 19 men, 95 cases in 72 women; mean age 74.2 years) who underwent TKA between 2009 and 2016 were enrolled. Weight-bearing  anterior-posterior (AP) radiographs of the lower extremity were taken preoperatively and 2 weeks after surgery. The hip-knee-ankle (HKA) angle, tibial plafond inclination (TPI), talar inclination (TI), and talar tilt (TT) were measured.
Results: Mean HKA, TPI, TI, and TT had decreased significantly by 2 weeks after surgery. Pearson correlation coefficient analysis showed that the change in HKA was correlated with changes in TPI and TI, the change in TPI was correlated with the changes in TI and TT, and the change in TI was correlated with the change in TT. Postoperative TT was significantly greater in the group with a preoperative HKA above 16° than in the group with a preoperative HKA below 16°. Postoperative TT was greater in the group with a postoperative HKA above 1.3° than in the group with a postoperative HKA below 1.3°.
Conclusion: Immediately after TKA for varus knee OA, correction of knee alignment had an impact on alignment of the ankle joint radiographically. Care is needed with regard to coronal alignment of the ankle joint when performing TKA in patients with an HKA above 16° and the target is HKA less than 1.3° during TKA.

Keywords: ankle joint, coronal alignment, total knee arthroplasty, varus, osteoarthritis

ISSN 1941-6806
doi: 10.3827/faoj.2017.1002.0002

1 – Department of Orthopedics, Institute of Biomedical Science, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
* – Corresponding author: sairyokun@hotmail.com


Osteoarthritis (OA) of the knee is an orthopedic problem worldwide, and affects a large proportion of the elderly population [1, 2]. OA causes varus deformation in the knee joint, resulting in abnormal alignment in the coronal plane. Currently, total knee arthroplasty (TKA) is the procedure most commonly performed for varus knee OA [3-5] and has proven to be very successful in restoring the alignment of the lower extremities.

In TKA, it is desirable to have a line between the center of the femoral head and the center of the ankle through the center of the knee. Although the focus of TKA is on the knee joint [6-10], acute correction in the alignment of the knee joint during TKA can cause compensatory changes in neighboring joints, including the orientation of the ankle.

It has also been reported that foot and ankle problems might be a source of pain after TKA as a result of changes in alignment of the legs [11-14]. However, there is limited data on the impact of change in the mechanical axis of the lower extremity immediately after TKA.

The purpose of this study was to investigate radiographic changes in coronal alignment of the ankle joint immediately after TKA rather than during longer-term follow-up. Our hypothesis was that TKA for severe varus knee OA has an immediate rather than a delayed effect on coronal ankle joint alignment.

Methods

This retrospective study was approved by the Institutional Review Board at Tokushima University Hospital. The patients involved provided informed consent for this report. A total of 125 cases in 91 patients (30 cases in 19 men, 95 cases in 72 women) who underwent primary TKA for symptomatic varus knee OA between 2009 and 2016 were enrolled. The patients had a mean age of 74.2 ± 7.7 years and a mean body mass index of 29.2 ± 3.8 kg/m². Patients with a history or signs of previous ankle trauma or surgery, congenital or developmental deformities, or inflammatory arthritis were excluded.

To evaluate the coronal alignment of the ankle joint on weight-bearing AP radiographs of the lower extremity, the following parameters were measured preoperatively and 2 weeks after surgery: (1) hip-knee-ankle (HKA) angle, the angle between a line from the center of the femoral head to the center of the knee (mechanical axis of the femur) and a line from the center of the knee to the center of the ankle (mechanical axis of the tibia); (2) tibial plafond inclination (TPI), the angle between the tangent of the tibial plafond and the horizontal line; (3) talar inclination (TI), the angle between the tangent of the talar dome and the horizontal line; (4) talar tilt (TT), the angle between the tibial plafond and the talar dome, which was calculated from the difference between the TI and TPI (Figure 1A, 1B). A positive HKA angle indicated varus knee alignment and a negative angle indicated valgus knee alignment. Positive TPI and TI values, which indicate medial inclination, were used to define an angle opening to the medial aspect. Therefore, a medial angle was considered to indicate positive varus. A positive TT value, which indicated varus alignment of the ankle joint, was used to define an angle opening to the lateral aspect. Therefore, a lateral angle was considered to indicate positive varus. Measurements were made on three occasions by an independent orthopedic surgeon who was blinded to the patient’s clinical information and the purpose of the study. The average of the three measurements was calculated.

Figure 1 Radiographic parameters for evaluation of coronal alignment of the knee and ankle joint on standing whole-leg anteroposterior radiographs. A. (1) The hip-knee-ankle (HKA) angle is formed by a line from the center of the femoral head to the center of the knee and a line from the center of the knee to the center of the ankle. A positive angle indicates varus knee alignment. B. (2) The tibial plafond inclination is defined as the angle between the tangent of the tibial plafond line and the horizontal line. A positive value indicates medial inclination. (3) Talar inclination is defined as between the tangent of the upper talus and the horizontal line. A positive value indicates medial inclination. (4) Talar tilt is defined as the angle between the tibial plafond inclination and the talar inclination. A positive value indicates varus alignment of the ankle joint. The dashed line indicates the ground.

Statistical analysis

All statistical analysis was performed using SPSS software ver. 24.0 (SPSS Inc, Chicago, IL). All data are reported as the mean ± standard deviation. Paired t-tests were used to evaluate changes in values between before and after surgery. The radiologic indices of the two groups were statistically analyzed using the independent t-test. Pearson correlation coefficients were used to determine the relationship between changes in HKA, TPI, TI, and TT after TKA. Continuous variables were compared between the two groups using the Mann-Whitney U test. A p-value < 0.05 was considered to be statistically significant.

Results

Preoperatively, 11 of 125 cases (8.8%) showed TPI (+), TI (+), and TT (-), indicating negative valgus TT (medial tilt), and 114 of 125 (91.2%) showed TPI (+), TI (+), and TT (+), indicating positive varus TT (lateral tilt). The orientation of the ankle joint became more parallel with the ground after TKA. Postoperatively, 17 of 125 cases (13.6%) showed a TPI (+), TI (+), and TT (-) pattern, 72 of 125 (57.6%) showed a TPI (+), TI (+), and TT (+) pattern, 7 of 125 (5.6%) showed a TPI 0, TI 0, and TT 0 pattern, 12 of 125 (9.6%) showed a TPI (-), TI (-), and TT (+) pattern, and 17 of 125 (13.6%) showed a TPI (-), TI (-), and TT (-) pattern (Table 1).

  Preoperative

n (%)

Postoperative

n (%)

TPI (+), TI (+), TT (-) 11 (8.8%) 17 (13.6%)
TPI (+), TI (+), TT (+) 114 (91.2%) 72 (57.6%)
TPI 0, TI 0, TT 0 0 7 (5.6%)
TPI (-), TI (-), TT (+) 0 12 (9.6%)
TPI (-), TI (-), TT (-) 0 17 (13.6%)

Table 1 Preoperative and postoperative TPI, TI, and TT.

The mean HKA decreased from 15.4° ± 5.9° preoperatively to 1.2° ± 2.1° at 2 weeks postoperatively. The medial inclination of the distal tibial joint surface and the upper talus decreased after TKA. The mean TPI decreased from 11.0° ± 5.0° preoperatively to 2.8° ± 4.5° after postoperatively, and the mean TI and mean TT decreased from 13.4° ± 5.8° to 3.6° ± 5.3° and from 2.2° ± 2.4° to 0.8° ± 1.8°, respectively. HKA, TPI, TI, and TT decreased significantly between preoperatively and 2 weeks postoperatively (p < 0.05 for all four parameters; Table 2). Pearson correlation coefficient analysis showed that the change in HKA was correlated with the change in TPI (r = 0.500, p < 0.05) and TI (r = 0.480, p < 0.05), the change in TPI was correlated with the changes in TI (r = 0.870, p < 0.05) and TT (r = 0.260, p < 0.05), and the change in TI was correlated with the change in TT (r = 0.285, p < 0.05; Table 3).

  Preoperative Postoperative

(2 weeks after TKA)

Correction P value
HKA 15.4º ± 5.9º 1.2º ± 2.1º 14.4º ± 5.9º *P < 0.05
TPI 11.0º ± 5.0º 2.8º ± 4.5º 8.4º ± 5.1º *P < 0.05
TI 13.4º ± 5.8º 3.6º ± 5.3º 10.0º ± 5.0º *P < 0.05
TT 2.2º ± 2.4º 0.8º ± 1.8º 1.5º ± 1.9º *P < 0.05

*A statistically significant difference between preoperatively and postoperatively. Abbreviations: HKA, hip-knee-ankle; TPI, tibial plafond inclination; TI, talar inclination; TT, talar tilt

Table 2 Corrective changes in HKA, TPI, TI, and TT.

    r P value
Correction

of  HKA

Correction

of TPI

0.500 *P < 0.05
  Correction

of  TI

0.480 *P < 0.05
  Correction

of TT

0.065 P = 0.478
Correction

of  TPI

Correction

of TI

0.870 *P < 0.05
  Correction

of TT

0.260 *P < 0.05
Correction

of TI

Correction

of TT

0.285 *P < 0.05

*Statistically significant difference between the two groups.

Table 3 Pearson correlation coefficient analysis of changes in HKA, TPI, TI, and TT.

Pearson correlation coefficient analysis also showed that the change in HKA was not correlated with the change in TT (r = 0.065, p = 0.478). However, the mean postoperative TT was significantly greater in the group with a preoperative HKA above 16° (HKA 20.4° ± 4.6°) than in the group with a preoperative HKA below 16° (HKA 11.2° ± 2.6°; TT 1.3° ± 1.9° and 0.7° ± 1.6°, respectively; p < 0.05; Table 4). The postoperative TT was greater in the group with a postoperative HKA above 1.3° (mean HKA 3.1° ± 1.3°) than in the group with a postoperative HKA below 1.3° (HKA -0.4° ± 1.3°; TT 1.4° ± 1.7° and 0.6° ±1.7°, respectively; p < 0.05; Table 5).

  Preoperative

HKA ≥ 16º

Preoperative

HKA < 16º

P value
Number of feet n = 55 (44.0%) n = 70 (56.0%)
Preoperative

HKA

20.4º ± 4.6º 11.2º ± 2.6º  
Postoperative

TT

1.3º ± 1.9º 0.7º ± 1.6º *P < 0.05

*A statistically significant difference between the two groups.

Table 4 Correlation between postoperative TT and preoperative HKA in the group with HKA 16° and the group with HKA < 16°.

  Postoperative

HKA ≥ 1.3º

Postoperative

HKA < 1.3º

P value
Number of feet n = 57 (45.6%) n = 68 (54.4%)
Postoperative

HKA

3.1º ± 1.3º -0.4º ± 1.3º  
Postoperative

TT

1.4º ± 1.7º 0.6º ± 1.7º *P < 0.05

*A statistically significant difference between the two groups (*P < 0.005).

Table 5 Correlation between postoperative TT and postoperative HKA in the group with HKA 1.3° and the group with HKA < 1.3°.

Discussion

Preoperatively, the ankle joint orientation line (TPI and TI) in all cases in this study was varus with respect to the ground line. Postoperatively, the ankle joint orientation line was close to parallel with the ground line and the TT was decreased. The change in alignment of the knee joint had a significant effect on alignment of the ankle immediately after TKA, rather than having a delayed effect seen only during long-term follow-up. However, in many cases, the medial inclination of TPI and TI and varus TT remained 2 weeks after surgery.

In our study, postoperative TT was significantly greater in the group of cases with a preoperative HKA above 16° (n = 55, 44.0%) than in the group with a preoperative HKA below 16° (n = 70, 56.0%). This finding indicates that the group with a preoperative HKA above 16° was significantly more likely to continue to have a positive TT (varus ankle joint) even after TKA. The postoperative TT was greater in the group with a postoperative HKA above 1.3° (n = 57, 45.6%) than in the group with a postoperative HKA below 1.3° (n = 68, 54.4%). Our study showed that the group with postoperative HKA above 1.3° was also significantly more likely to continue to have a positive TT (varus ankle joint) even after TKA. Therefore, we recommend a cautious approach to coronal ankle joint alignment when performing TKA for severe varus knee OA, especially when the HKA is above 16°. Gursu et al. reported that leaving residual varus in the knee could be considered in order to prevent malalignment of the ankle joint [14], but we suggest aiming for an HKA below 1.3° during TKA.

An important strength of this study is its large sample size when compared with other studies. It is very difficult to retain such a sample size for the duration of a study. The outcomes evaluated in our study provide important information regarding alignment of the ankle joint immediately after TKA. To our knowledge, this is the first report to demonstrate that TKA for severe varus OA knee has an effect on coronal alignment of the ankle joint immediately rather than gradually.

One limitation of this study was that subtalar joint mobility was not investigated and radiologic assessment of hindfoot alignment was not performed. Alignment of the hindfoot changes when alignment of the knee joint changes [15, 16]. Most of the compensation for angular deformity of the knee joint occurs in the subtalar joint [17]. When varus knee with limited subtalar joint motion loses the compensatory function of the subtalar joint, varus deformity of the knee is compensated by valgus alignment of the ankle joint [12, 17, 18]. In this study, 11 of 125 cases (8.8%) showed varus of the ankle joint, which means a TPI (+), TI (+), and TT (-) pattern. In these cases, subsequent foot/ankle pain or disability may occur after TKA because the subtalar joint may not be able to reorient itself after knee realignment because of rigid hindfoot deformity.

Another limitation was that the results were based only on radiologic assessment two weeks after TKA without clinical assessment. It is possible that realignment of the knee joint effects symptoms in the ankle joint after TKA [19-24]. Moreover, the acute change in alignment of the ankle joint, together with the changes in the biomechanics of the ankle joint, changes the contact area of the tibiotalar joint and consequently contributes to increasing pressure on articular cartilage and accelerated degeneration of the ankle joint [25]. When degenerative changes and angular deformities of the knee are severe, a varus deformity is usually three-dimensional and associated with flexion contracture of the knee, and the varus angle measured on radiographs may not be a true varus angle [26, 27].

In conclusion, the change in alignment of the knee joint by TKA for varus knee OA influenced the alignment of the ankle joint immediately after surgery in this study. Examination and assessment are required not only at the knee joint but also at the ankle joint before TKA. More careful follow-up of the ankle after TKA should be considered when TKA is performed in patients with HKA above 16° and the aim should be to keep HKA below 1.3° during the procedure.

Acknowledgements

Conflicts of Interest and Source of Funding

No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were obtained in support of this study.

Funding declaration: No funds were obtained in support of this study.

Conflict of interest declaration: No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

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Isolated, nondisplaced medial cuneiform fractures: Report of two cases

by Koun Yamauchi MD1*, Satoru Miyake MD1, Chisato Kato MD1, Takayuki Kato MD1

The Foot and Ankle Online Journal 10 (2): 1

Isolated, nondisplaced medial cuneiform fractures are difficult to diagnose using plain radiographs. Computed tomography (CT) or magnetic resonance imaging (MRI) are necessary to aid in diagnosis. This paper describes two patients with this fracture that were more difficult to suspect because the fractures occurred during running, which are extremely rare. Tenderness and swelling around the medial cuneiform was observed that led to suspicion of a fracture; this lead us to perform a CT scan or MRI for confirming the presence of the fracture. However, tenderness and swelling around the midfoot can be observed in a patient with a sprain without the fracture. Therefore, it is more important to note that isolated, nondisplaced medial cuneiform fracture can be induced by an indirect force such as that occurring while running.

Keywords isolated medial cuneiform fractures, non-displaced, during running, computed tomography, magnetic resonance imaging

ISSN 1941-6806
doi: 10.3827/faoj.2017.1002.0001

1 – Department of orthopedic surgery, Akita Hospital, Takara, Chiryu City, Aichi 472-0056, Japan.
*Corresponding author: Koun Yamauchi, koun_yamauchi@yahoo.co.jp


Here, we describe two consecutive patients with isolated, nondisplaced medial cuneiform fractures that occurred during running. Cuneiform fractures generally occurs along with other fractures of the midfoot, such as Lisfranc dislocation fractures, whereas the occurrence of isolated medial cuneiform fracture is rare. A total of only seven published case reports have been reported in the literature [1-5]. Nevertheless, an isolated, non-displaced fracture of the medial cuneiform may be easily suspected when the midfoot has been bruised by a direct, intense force, such as the impact of a traffic accident. However, it may be more difficult to suspect the fracture when being caused by indirect and acute force. Only one case report clearly describes the mechanism of isolated, nondisplaced medial cuneiform fracture being caused by indirect and acute force that occurred during dancing [4]. Therefore, the occurrence of isolated medial cuneiform fracture during running is extremely rare.

Case Report #1

A 25-year-old woman visited a hospital after hearing a cracking sound and feeling pain in her right midfoot during short-distance running at full speed in a park. Clinicians at the hospital diagnosed her injury as a sprain because they found no indications of fracture. Two days later, she visited our hospital with tenderness and swelling around the midfoot. However, radiograph of the midfoot showed no indications of a fracture (Figure 1), and we diagnosed her injury as a sprain.

Figure 1 Plain radiographs of the foot in first case. White arrows show cuneiform bone. (a) anterior–posterior image; (b) lateral–medial image; (c) oblique, lateral–medial image; and (d) oblique, medial–lateral image.

Five days later, she came for an examination; the tenderness and swelling around the midfoot persisted, although the spontaneous pain was gradually decreasing. We performed a computed tomography (CT) scan, which indicated an isolated, nondisplaced medial cuneiform fracture (Figure 2).

Figure 2 Computed tomography of the foot in the first patient. White arrows show fracture line. Dotted lines in axial image (a) show reference lines for coronal image (b) and sagittal image (c).

Her treatment included non weight-bearing (NWB) activity for two weeks without any immobilization. An arch support was applied on her right foot. Partial weight-bearing (PWB) activity was allowed from the fourth week after the injury, full weight-bearing (FWB) activity was allowed from the sixth week after the injury, and she was treated in rehabilitation from the fourth week to three months after the injury. At two months after injury, her hallux range of motion (ROM) recovered to the level of the contralateral side hallux ROM; however, swelling around the midfoot persisted but disappeared at three months after injury. We conducted a self-score, self-administered foot evaluation questionnaire (SAFE-Q) at two and three months after the injury [6]. The following were the scores at two and three months after injury, respectively: Pain scores: 54.1 and 76.4; activities of daily living (ADL) scores: 65.9 and 91.0; social functioning scores: 0.4 and 82.5; shoe-related scores: 41.7 and 91.7; and general health scores: 60 and 90.0 (Full score for each subscale was 100 points).

Case Report #2

A 35-year-old woman presented at our hospital with tenderness and swelling around the midfoot. She had felt sharp pain in her right midfoot as she dashed up an acute slope. Radiographs taken during first examination showed no indication of a fracture (Figure 3), but CT scan showed an isolated, nondisplaced medial cuneiform fracture (Figure 4). Furthermore, magnetic resonance imaging (MRI) showed an acute fracture of the medial cuneiform (Figure 5).

Figure 3 Plain radiographs of the foot in second patient. White arrows show cuneiform bone. (a) anterior–posterior image; (b) lateral–medial image; (c) oblique, lateral–medial image; and (d) oblique, medial–lateral image.

Figure 4 Computed tomography of the foot in the second patient. White arrows show fracture line. Dotted lines in axial image (a) show reference lines for coronal image (b) and sagittal image (c).

Figure 5 Magnetic resonance imaging (MRI) of the foot in the second patient. White arrows show fracture area in coronal images of T1-weighted image (a), T2-weighted image (b), and T2-weighted image with fat saturation sequence (c).

Her treatment included NWB activity for three weeks and immobilization with a soft-splint because of significant swelling. At three weeks after the injury, we started the same treatment strategy as that with the first patient. At two months after injury, her hallux ROM had recovered to the level of contralateral side hallux ROM, and swelling around the midfoot was no longer apparent. SAFE-Q scoring was conducted at 2, 3, and 8 months after injury. Following were the scores at 2, 3, and 8 months after injury, respectively: Pain scores: 76.7, 91.4, and 99.9; ADL scores: 75.0, 93.2, and 97.7; social functioning scores: 83.3, 82.4, and 100; shoe-related scores: 83.3, 58.3, and 91.7; and general health scores: 80, 90.0, and 100.

Discussion

Similar to earlier reports on diagnosis and treatment of an isolated, non-displaced medial cuneiform fracture [1-5], we were not able to diagnose the fracture in either of our patients based on the plain radiographs alone. All authors have reported that it was difficult to diagnose an isolated, non-displaced medial cuneiform fracture using plain radiographs and that CT and MRI were necessary to diagnose this fracture.

Observed tenderness and swelling around the medial cuneiform bone lead to suspicion of a fracture; this lead us to perform a CT scan or an MRI for confirming the presence of the fracture. An isolated, non-displaced fracture of the medial cuneiform may be easily suspected when the midfoot has been bruised by a direct, intense force, such as the impact of a traffic accident, whereas the stress fracture of this bone can be suspected when the feet of athletes are subjected to repetitive, physical loads. However, when the midfoot is subjected to indirect and acute one-time force, such as dancing or running, clinicians may not perform a CT scan or MRI because they generally do not suspect the occurrence of a fracture, thereby diagnosing the tenderness and swelling around the midfoot as a sprain and/or bruise. Therefore, our suspicion of the isolated, nondisplaced medial cuneiform fracture is noteworthy even when the patient’s midfoot has been subjected to indirect and acute one-time force during running. Although the bipartition of the medial cuneiform was not observed in both our patients, a clinician should suspect the presence of midfoot pain related to the bipartition of the medial cuneiform bone as a differential diagnosis. Steen et al [7] proposed that the bipartition of the medial cuneiform can be associated with midfoot pain following an acute injury.

As reported in the earlier reports, treatment for isolated, nondisplaced medial cuneiform fracture can be conservative [3, 5]. In both of our patients, CT scan taken at five weeks after injury exhibited bony union without complications, such as malunion or displacement. Although the patient’s hallux ROM showed recovery two months after injury, SAFE-Q scores remained unfavorable. In particular, SAFE-Q scores of the first patient were worse, which could have resulted from persistent swelling around her midfoot. At three months after injury, the SAFE-Q scores were better in both patients, except the shoe-related scores of the second patient. We were not able to ascertain any causes for the low shoe-related scores in the second patient. At eight months after injury, the SAFE-Q scores were almost full scores in the second patient, while the SAFE-Q scores were not conducted in the first patient.

Interestingly, CT scan exhibited a similar fracture type in both patients: dorsal and plantar bone fragment with avulsion fracture of the lateral–distal–plantar cortex. Because the fractures in both patients included joint surfaces (navicular–cuneiform joint and cuneiform–metatarsal joint), bone fragment displacement was contraindicated. Therefore, surgery using embedded screws may be an appropriate treatment option for fixation of dorsal and plantar bone fragments. Surgery, such as definitive fixation, is likely to maintain non-displacement until bony union is achieved. Definitive fixation is particularly appropriate for athletes because it enables early and successful recovery (because athletes are able to actively return to their respective sports sooner) compared to conservative treatment. We strongly suggest that more study is needed to assess the effect of surgical treatment options on recovery after isolated, nondisplaced medial cuneiform fracture.

Conclusion

Isolated medial cuneiform fracture can be induced by an indirect force while running and should be diagnosed by CT and MRI.

Acknowledgements

Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent:  Informed consent was obtained from all individual participants included in the study.

Funding declaration and Conflict of Interest:  This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. There are no conflicts of interest to declare.

Reference

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Spring 2017


Issue 10 (1), 2017


Small-vessel vasculitis: A review and case report
by Kinna A. Patel, DPM


Retained foreign body in the foot presenting as tenosynovitis of the flexor digitorum longus tendon
by Muhammad Haseeb, Muhammad Farooq Butt, Khurshid Ahmad Bhat


Clinical clearing of moderate and severe onychomycosis with the Nd:YAG 1064nm laser and post treatment prevention with tolnaftate
by Myron A. Bodman DPM, Marie Mantini Blazer DPM, Bryan D. Caldwell DPM, Rachel E. Johnson DPM


Raynaud’s-like symptoms induced by prescription medication
by Robert L. van Brederode, DPM, FACFAS


Temporary bridge plating of the medial column in Chopart and Lisfranc injuries
by Alaa Mansour DPM, Lawrence Fallat DPM, FACFAS


A unique presentation of recurrent cavus foot of an adolescent patient with Marfan syndrome: A case report
by Kaitlyn L. Ward DPM, Philip R. Yearian DPM, FACFAS


Letter to the Editor – Response
by Edward S Glaser and David Fleming