Tag Archives: fusion

Talectomy (astragalectomy) and tibiocalcaneal arthrodesis following traumatic talus fracture-dislocation

The Foot and Ankle Online Journal 12 (2): 4

by Dr Alison Zander, MBBCh, BSc (hons), MSc (PHNutr)1, Mr Anirudh Gadgil, MBBS, M.S. (Orth), FRCS (Ed), FRCS (Trauma & Ortho)2, Derek Protheroe, BSc(Hons), MSc, PgDip3*

Talus fractures occur rarely but are often associated with complications and functional limitations. Urgent reduction of associated dislocations is recommended with open-reduction and internal fixation of displaced fractures when adjacent soft tissue injury permits [1]. However, it is important to remember that there is a high incidence of long term complications, along with a significant impact on activities of daily living and quality of life.  This case report describes the successful treatment of a severely comminuted talar fracture dislocation with primary talectomy and tibio-calcaneal arthrodesis. A reminder that in selected cases that the talectomy (astragalectomy) may be a viable alternative.

Keywords: talus, comminuted, tibiocalcaneal arthrodesis, fusion, talectomy, astragalectomy, trauma, avascular-necrosis, AVN

ISSN 1941-6806
doi: 10.3827/faoj.2018.1202.0004

1 – Foundation Doctor, Cardiff and Vale University Health Board, University Hospital of Wales, Heath Park, Cardiff
2 – Consultant Orthopaedic Surgeon, Cardiff and Vale University Health Board, University Hospital of Wales, Heath Park, Cardiff
3 – Advanced Podiatry Practitioner, Prince Philip Hospital, Bryngwyn Mawr, Llanelli, Wales, SA14 8QF
* – Corresponding author: Derek.Protheroe@wales.nhs.uk


Talus fractures account for less than 1% of all fractures, they may be caused by high-energy trauma, and any other form of forced dorsiflexion injury to the ankle and foot [1]. Talar fractures may be classified anatomically as head, neck, body, lateral or posterior processes, displaced or non-displaced. A range of classifications have been established such as the original Hawkins, then modified by Canale & Kelly and then the Sneppe classification [2]. These sub-classifications help to guide treatment options[3]. Non-displaced fractures may be treated conservatively with a non-weight-bearing short-leg cast, whereas displaced fractures require open-reduction and internal fixation. Reconstruction after a talus fracture poses the greater surgical challenge if restoration of the articular surfaces is precluded secondary to comminution [4]. The talus is the second largest of the tarsal bones, with more than half of its surface being covered with articular cartilage, with no muscular attachments[1]. Therefore, the vascular supply of the talus is well-known to be tenuous, therefore predisposing the talus to significant ischemic injury after fractures [5]. Risk of post-traumatic avascular necrosis (AVN) increases with the magnitude of injury [6]. Extensive intraosseous anastomoses are present throughout the talus and are responsible for its survival during severe injuries. At least one of the three main anastomoses preserved may potentially allow adequate circulation via anastomotic channels [1].

Using the Hawkins’s classification system; 0-13% for grade I, 20-50% for grade II, 83-100% for grade III, and 100% for grade IV fracture dislocations result in AVN [1,6]. 

Clinical experience of talar fracture assessment and management is limited by their infrequent incidence, which is further exacerbated by the numerous sub-classifications of fracture, as previously alluded to. Case reports, although regarded as level V evidence can aid and develop an understanding of the risks and benefits of treatment options to achieve optimal patient outcomes [7].  Clinicians should maintain a high index of suspicion for AVN, which can only be diagnosed radiographically six to eight weeks following injury [8].  Furthermore, the potential for long term issues, such as hind-foot arthrosis and further revisionary surgery must be considered, alongside risks of repeated anesthetics for multiple procedures after complications. Approximately 25% of talus dislocations treated with internal reduction require additional surgery, including secondary arthrodesis [9].

Operative treatment measures for this area may be broadly split into two categories; joint sparing procedures – such as protected weight bearing, patella loading splints and bone graft or joint sacrifice procedures – such as talectomy and arthrodesis. Total talectomy and tibiocalcaneal arthrodesis may be viewed as a salvage procedure in this case report due to the case of severe comminuted fracture, where it may be impossible to anatomically reduce the talus and allow for adequate stable fixation. 

A literature search was performed using the keywords ‘talectomy’, ‘astragalectomy’, ‘fracture’, ‘tibiocalcaneal arthrodesis’ and Boolean search terms. Ovid SP databases (including embase & medline) was used with no exclusion dates to allow for a search of all historical literature. It appears that there was only one other reference in 1955 to such a procedure following a traumatic fracture to the talus body [10]. Historically, this case involved a Royal Navy soldier, where following a dislocated fracture a primary talectomy and tibiocalcaneal arthrodesis was performed.

Figure 1 Preoperative radiographs lateral and AP views.

Case Report

A sixty eight-year-old lady with no significant past medical history presented to Accident and Emergency.  She had been a seat-belted, front-seat passenger of a car that suffered a high-speed head-on road traffic collision.  She sustained a grade I (Gustilo-Anderson) open, comminuted fracture dislocation of the talus (Figure 1) with puncture wounds on the lateral aspect of the talus.  The foot was neurovascularly intact initially. The ankle was manipulated and back-slab applied. Apart from body ache and multiple minor abrasions and bruises there were no other injuries.  Whilst she was waiting on the ward to have a CT scan performed she developed increasing pain in foot, numbness of toes and sluggish capillary refill in the toes, which were not relieved even after removing the plaster slab.  She was counselled that she would need to be rushed to the operating room to attempt to reestablish circulation to her foot with a plan to open reduce the fracture and stabilize it. She was also made aware of the possibility of having to excise the fragments if it was not possible to operatively stabilize the fracture.

Procedure

Under spinal anaesthesia, antibiotic cover and usual sterile draping, the lateral puncture wounds were thoroughly debrided and lavaged with saline.  The fracture was exposed using an anterior approach between tibialis anterior and extensor hallucis longus, carefully protecting the neuro-vascular bundle throughout the procedure.  The displaced fracture fragments of the talus, the medial malleolus and the medial hematoma all appeared to have caused pressure on the posterior tibial neurovascular bundle. 

Figure 2 One year follow-up radiographs.

This was relieved after opening the fracture and the toes regained their color.  Intra-operatively, it became apparent that the fracture could not be anatomically reduced and fixated adequately due to the severe degree of comminution, and lack of any soft tissue attachments to the majority of the fragments. Hence, the original plan of anatomical reduction and internal fixation of the fracture was abandoned.  All loose fragments were excised, which involved removing all of the posterior process and body of the talus. Using the cancellous bone from the excised fragments as autogenous graft, the calcaneal and tibial articular surfaces were fused using three 7.5 mm cannulated AO screws (Figure 2). A small lateral malleolar avulsion fragment was excised.  The medial malleolus fragment was reduced and fixed with a cancellous 4mm AO screw (Figure 2). Post-operatively, the foot was observed to be well-vascularised. The lateral wounds were allowed to heal with regular dressings and a plaster of Paris splint was applied.  

Postoperative care protocol

Postoperatively, the patient received intravenous antibiotics for 24 hours, limb elevation for 48 hours and prophylactic anticoagulation for six weeks. Mobilization started with physiotherapy, consisting of non-weight bearing for six weeks, partial-weight bearing in air cast boot for two weeks and then allowed to fully-weight bear with an air cast boot.  The patient was advised to stop using the air cast boot at three months. The wounds healed well and there were no other complications.  

Outcomes

Due to the urgency of care required and history of trauma it was not deemed appropriate to use any form of patient reported outcome measure at the time of incident. However, the patient was reviewed frequently for eight weeks until the wounds healed. Then, accordingly, when she was allowed to weight bear, again at six months, one year and two years post-injury.  At six months, the patient had no pain or tenderness, with some dorsiflexion and plantar flexion possible at the mid-tarsal level. One-year follow-up showed that the tibio-calcaneal fusion was solid via plain x-ray (Figure 2). Final follow up at two years, she had a 2 cm shortening of her right leg measured in a weight bearing manner (measured blocks) and appropriate footwear adaptations were incorporated on the right side.  She is very happy with the outcome, has no pain and is fully mobile and weight bearing without support. 

Discussion

Talus fractures occur rarely and are commonly associated with complications and functional limitations [11].  The main complication being osteonecrosis, Vallier et al reviewed 100 talus fractures and reported osteonecrosis with collapse (31%), ankle arthritis (18%), subtalar arthritis (15%). Operative intervention was complicated by superficial (3.3%) and deep infection (5%), wound dehiscence (3.3%), delayed union (1.7%) and non-union (3.3%) [11]. Restoration of the axial alignment has been recommended to ensure optimisation of ankle and hindfoot function. It has been reported that tibiotalar and subtalar ranges of motion are reduced by up to 50% and arthrosis occurs in roughly 50% of fractures classified as Hawkins type III and IV [4]. The original paper proposing Hawkins classification even stated that comminuted fractures or those involving the body of the talus, were believed to be more problematic injuries and outside the scope of his original article [12].

A range of classifications for talus fractures exist, the most famous being the original Hawkins classification [2]. 

Historically, cases of talus injuries date as far back to as 1608. Interestingly, a term was coined known as ‘aviator’s astragalus’ due to its high frequency of injury in aircraft accidents [12]. The first case of talectomy for compound fracture was reported in 1609 by Hildanus  [13]. The patient had jumped over a ditch and turned his ankle on landing, causing the talus to dislocate completely out of the skin.  The talus was removed completely, following which the man was seen walking without apparent discomfort. In 1931, Whitman reported use of astragalectomy in correction of a calcaneus deformity of the foot [14]. Although these accounts are reported anecdotally, they demonstrate that the procedures used then are used in a similar fashion to case descriptions today. Talectomy has been used as a salvage procedure in correction of pathological deformity in conditions like  Charcot-Marie-Tooth, neglected idiopathic clubfoot, neurogenic clubfoot, cerebral palsy, gunshot wound, hemiplegia secondary to head trauma, Volkmann ischaemic contracture, poliomyelitis, arthrogryposis, myelomeningocele, and Charcot arthropathy  [15-18]. Talectomy has been used for patients with osteomyelitis or osteonecrosis of the talus [19,20]. We found only one study which reported 4 cases of total talectomy for Hawkins Type III fractures dislocations of talus in 1993 [21].  However, tibiocalcaneal arthrodesis was formally not carried out in the patients in this series.

Detenbeck and Kelley (1969) reported dire results following total dislocation of the talus in nine cases, of which seven were open [22]. Eight of the nine developed sepsis; seven required secondary talectomy, five with tibio-calcaneal fusion. This report highlights the serious consequences of this kind of injury. Their recommendations were to apply a more aggressive approach to initial treatment using talectomy and some form of tibio-calcaneal arthrodesis as the primary treatment for fracture-dislocation of the talus.  

Predominantly, cases of tibio-calcaneal (TC) arthrodesis are described for treatment of post-traumatic AVN of the talus or for treatment of rheumatoid arthritis [23-25]. Authors have reported TC arthrodesis of nine ankles in eight patients; seven were for post-traumatic talar AVN and one for rheumatoid arthritis [25]. Fixation was achieved using 6.5 or 7mm cannulated screws or multiple staples, with autologous cancellous bone graft.  Fusion was achieved in all patients between 12 and 40 weeks with a 2cm leg length discrepancy. Complications included local infection, malunion, wound dehiscence, prominent fibula and two patients required supplemental external fixation.  

In 1972, Reckling reported early TC fusion after displaced talus fractures in eight feet; Steinmann pins were used to achieve fixation without the use of bone grafting [26].  No wound complications were reported and bone union was achieved within 17 weeks. 

The main draw-back of TC fusion is the shortening of 2 to 3 cm that is produced in the limb.  It is also possible that secondary arthrosis of other joints of the foot may occur over time after TC fusion.

Using the technique of tibio-calcaneal fusion there is a potential to increase the calcaneal pitch angle. Intra-operatively, the surgeon must be careful to keep this in mind and achieve a well-aligned position of the foot. 7.5 mm cannulated AO screws were utilised providing stable compression across the fusion surfaces and encouraged rapid fusion of the inferior tibial surface to calcaneal articular surface.  There are other modes of fixation discussed within the literature such as intramedullary nail, pre-contoured plates or an external fixator. This would depend not only the surgeon’s experience and preference but in this case the setting (trauma) and clinical scenario due to the compromised blood supply.

Dennison et al treated six patients who had previous failed surgery and suffered post-traumatic AVN of the talus [27]. The necrotic body of the talus was excised and TC fusion achieved using an Ilizarov frame, combined with corticotomy and a lengthening procedure.   Patients were aged between 27 and 67 years. Shortening was corrected in four patients, and bony fusion achieved in all. Four out of six patients reported good or excellent results. 

Thomas and Daniels in 2003 reported using talonavicular and subtalar arthrodesis as a primary fusion to treat a three week old Hawkins type IV traumatic comminuted neck of talus fracture in a 29-year-old man [28]. Their case had similarities to ours, in that open reduction internal fixation had been planned, however, this was not possible anatomically due to the degree of comminution.  The patient underwent 16 months of follow-up and despite successful fusion without avascular necrosis, he was unable to return to his job as a roofer. 

Hantira et al reported treating a comminuted open fracture of the body of the talus on the same day of injury by tibio-talar fusion using the Blair technique [29].  Küntscher nails and cancellous screws remained in situ while the graft healed and they were removed at four and eight weeks post-surgery, respectively.  The patient started active and assisted foot exercises 14 weeks following surgery, with partial-weight bearing on crutches 20 weeks after the injury.  Fusion was complete at 10 months after injury and the patient was reportedly almost pain free.

Conclusion

The severity of talus fractures has increased over the last 3 decades due to modern safety equipment resulting in higher survival rates from serious accidents [2]. Due to recent advances in surgical and fixation techniques, the tendency is to reduce the talar fractures as anatomically as possible and stabilize them with screws.  

It is worthwhile considering the option of a talectomy in conjunction with a primary tibiocalcaneal arthrodesis. although cases of talus fractures with comminuted dislocations are rare. In this particular case study, to attempt to perform an open reduction and internal fixation procedure may have increased the potential risk and complications associated with these procedures, mainly AVN, traumatic hind foot arthrosis both potentially requiring further surgery. Ultimately, increasing the potential for a high rate of long-term complications and a significant impact on activities of daily living and quality of life after such treatment [30].

In summary, surgeons should be flexible in their approach in regards to consideration of treatment options in order to maximise patient outcomes.  This case highlights that the procedure choice of a primary talectomy and tibio-calcaneal arthrodesis is a viable treatment option for traumatic dislocated comminuted talar fractures, which intra-operatively was unable to be anatomically reduced and fixated.

Funding declaration: None  

Conflict of interest declaration: None

References

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  3. Lamothe JM and Buckley RE. Talus fractures: a current concepts review of diagnoses, treatments, and outcomes. Acta Chir Orthop Traumatol Cech. 2012; 79(2):97-106.
  4. Ptaszek, A (1999) Immediate Tibiocalcaneal Arthrodesis with Interposition Fibular Autograph for Salvage After Talus Fracture: A Case Report. Journal of Orthopaedic Trauma. 13(8): 589-592.
  5. Pearce DH, Mongiardi CN, Fornasier VL, Daniels TR. Avascular necrosis of the Talus: A pictorial essay. RadioGraphics. 2005; 25(2):399-410. 
  6. Balaji GG and Arockiaraj J. Bilateral talus fracture dislocation: is avascular necrosis inevitable? BMJ Case Rep. Aug 25;2014. pii: bcr2014205367. doi: 10.1136/bcr-2014-205367
  7. Cutler L and Boot DA. Complex fractures, do we operate on enough to gain and maintain experience? Injury. 2003; 34(12):888-91.
  8. Melenevsky Y, Mackey RA, Abrahams RB, Thomson NB. Talar Fractures and Dislocations: A Radiologist’s Guide to Timely Diagnosis and Classification. Radiographics. 2015; 35(3):765-79.
  9. Weston JT, Liu X, Wandtke ME, Liu J, Ebraheim NE.  A Systematic Review of Total Dislocation of the Talus. Orthop Surg. 2015; 7(2):97-101. 
  10. Marsden CM (1955). Ankle fusion after complete talectomy in fracture dislocation of the talus. Journal of the Royal Army Medical Corps. 101(1):60-2.
  11. Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeorzan BJ. Talar neck fractures: results and outcomes. Journal of Bone & Joint Surgery. 86: 1616-1624.
  12. Alton T, Patton DJ, O.Gee A (2015) Classification in Brief: The Hawkins Classification for Talus Fractures. Clinical Orthopaedics and Related Research. 473(9): 3046-49.
  13. Hilandus F (1608): Report quoted in Opera, quae extant omnia (1946), Obs. 67, p. 140. Francofurti ad Moenum : Beyer.
  14. Whitman A , Astragalectomy – Ultimate Result.  Americal Journal of Surgery. 1931; 11(2):357–358.
  15. Gursu S, Bahar H, Camurcu Y, Yildirim T, Buyuk F, Ozcan C, et al.  Talectomy and Tibiocalcaneal Arthrodesis with Intramedullary Nail Fixation for Treatment of Equinus Deformity in Adults. Foot Ankle Int. 2015 Jan; 36(1):46-50. doi: 10.1177/1071100714550649
  16. Ruet A, Desroches A, Pansard E, Schnitzler A, Denormandie P.  Role of talectomy in management of severe equinovarus deformity in adults. Annals of Physical and Rehabilitation Medicine. 2014 May; 57:e197. doi: 10.1016/j.rehab.2014.03.719
  17. Joseph TN and Myerson MS. Use of talectomy in modern foot and ankle surgery  Foot Ankle. Clin N Am. 2004; 9:775–785.
  18. Daghino W, Di Gregorio G, Cerlon R. Surgical reconstruction of a crush injury of the talar body: a case report. J Bone Joint Surg Am. 2011 Jul; 93(14):e80.
  19. Stapleton JJ, Zgonis T. Concomitant Osteomyelitis and Avascular Necrosis of the Talus Treated with Talectomy and Tibiocalcaneal Arthrodesis. Clin Podiatr Med Surg. 2013 Apr; 30(2):251-6. doi: 10.1016/j.cpm.2013.01.001
  20. Kharwadkar N, Nand S, Walker AP. Primary talectomy for severe fracture-dislocation of the talus with a 15-year follow up: case report. Foot Ankle Int. 2007; 28(2):272-275.
  21. Gunal I, Atilla S, Araç S, Gürsoy Y, Karagözlu H. A new technique of talectomy for severe fracture-dislocation of the talus. J Bone Joint Surg Br. 1993 Jan; 75(1):69-71.
  22. Detenbeck LC and Kelly PJ. Total Dislocation of the Talus. J Bone Joint Surg Am. 1969 Mar; 51(2):283-288.
  23. Cinar M, Derincek A, Akpinar S. Tibiocalcaneal arthrodesis with posterior blade plate in diabetic neuroarthropathy. Foot Ankle Int. 2010; 31(6):511-516
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  27. Dennison MG, Pool RD, Simonis RB, Singh BS. Tibiocalcaneal fusion for avascular necrosis of the talus. J Bone Joint Surg Br. 2001; 83(2):199–203.
  28. Thomas RH, Daniels TR. Primary fusion as salvage following talar neck fracture: a case report. Foot Ankle Int. 2003 Apr; 24(4):368-71. 
  29. Hantira H, Al Sayed H, Barghash I. Primary ankle fusion using Blair technique for severely comminuted fracture of the talus. Med Princ Pract. 2003 Jan-Mar; 12(1):47-50E
  30. Stake IK, Madesan JE, Hvaal K, Johnsen E. Surgically treated talar fractures. A retrospective study of 50 patients. Foot and Ankle Surg. 2016; 22:85-9.

Intramedullary rodding of a toe – hammertoe correction using an implantable intramedullary fusion device – a case report and review

by Christopher R. Hood JR, DPM, AACFAS1, Jason R. Miller, DPM, FACFAS2pdflrg

The Foot and Ankle Online Journal 9 (4): 1

Development of a hammertoe is a commonly encountered problem by the foot and ankle surgeon. In long-standing deformity, the pathologic toe becomes fixed with patient complaints of pain, corns, and calluses and, in the immunocompromised patient, ulceration with potential infection and amputation. A common correction of the deformity is through lesser toe interphalanageal arthrodesis, commonly performed at the proximal joint. There are numerous techniques and new devices on the market to help assist in holding position until fusion is achieved.  The author demonstrates a case report utilizing a fixation device that has characteristics similar to that of an intramedullary rod. Additionally, a retrospective, observational study involving 35 toes that have undergone an arthrodesis procedure of the proximal interphalangeal joint using an intramedullary fusion device to stabilize the fusion site is reviewed. This device imparts its stability in a manner similar to that of intramedullary rods in long bone fixation.

Keywords: ArrowLokTM, arthrodesis, digit(al), fusion, hammertoe, implantable device, intramedullary, surgery, Kirschner wire

ISSN 1941-6806
doi: 10.3827/faoj.2016.0904.0001

1 – Premier Orthopaedics and Sports Medicine, Malvern, PA, Malvern, PA
2 – Premier Orthopaedics and Sports Medicine, Malvern, PA, Fellowship Director, Pennsylvania Intensive Lower Extremity Fellowship, and Residency Director, Phoenixville Hospital PMSR/RRA, Phoenixville, PA
* – Corresponding author: Christopher R. Hood JR, DPM, AACFAS, crhoodjr12@gmail.com


The hammertoe deformity is one of the most common presenting problems and surgical corrections encountered and performed by the foot and ankle surgeon [1,2]. Correction through lesser interphalangeal (proximal interphalangeal joint, PIPJ, or distal interphalangeal joint, DIPJ) resection and fusion was first described by Soule in 1910 [1]. Since then many modifications have been made to the procedure from various methods of bone preparation at the fusion site to extramedullary (EM) Kirschner wires (KW) and intramedullary (IM) fusion devices (IMFD) to stabilize the fusion site until osseous healing has been achieved [1, 3-6].

The choice to adapt fixation from EMKW to IMFD buried inside the bone stemmed from the desire to improve surgical outcomes, namely decreasing surgical site infection (SSI) rates among other inherent problems with KW use [5]. Since their introduction onto the market, many of these new have held true in decreasing these complication rates, achieving similar outcomes regarding fusion rates, with the bonus of higher patient satisfaction and a decreased (almost eliminated) infection rate [2, 7-10].

Here we present an example of an IMFD, different in construct than others on the market, which has not yet been reported on. This device gives another option to the surgeon when it comes time for digital fusion procedures with the added versatility of various lengths when multiple digital joints need to be fused simultaneously. The construct of this device, unlike others, garners its strength and stability from its length, purchasing the subchondral bone plate and acting in a manner similar to an intramedullary rod used in other orthopaedic fixations scenarios.

Methods

Case Report

Our patient, a 49 year-old female, presented with a chief complaint of a right second toe deformity. Conservative measures of strapping, padding, and shoe modifications were attempted, but ultimately failed. She elected to proceed with arthrodesis of the digit. She was followed at post-op weeks 2, 4, and 8. At week 8, osseous bridging was noted across the osteotomy site (Figure 1). The patient had no complaints and was discharged. She returned to the office 2 years later for a different complaint and x-rays revealed fusion across the PIPJ with no loss in hardware fixation (Figure 2).

fig1a fig1b

Figure 1 Case report patient at (left) 2 weeks and (right) 8 weeks post-operation. Note fusion on medial side of arthrodesis site at 8 weeks.

fig2

Figure 2 Case report patient seen 2 years later. Complete fusion with no loss of fixation.

 

Surgical Technique

A #15 blade is used to make an incision across the PIPJ of the digit. This is dissected down to the deep capsule taking care to create a surgical plane between the superficial and deep fascial layers. Retraction is utilized to protect neurovascular structures located around the digit. A transverse tenotomy of the long extensor is performed just proximal to the PIPJ and soft tissues are freed up from the proximal phalanx head and middle phalanx base. Cartilage resection is performed with a sagittal saw at the head of the proximal phalanx and base of the middle phalanx.

Implantation of the IMFD is performed per the devices surgical technique guide. First, the IM canals of the proximal and middle phalanx are reamed with the supplied 1.6mm diameter reaming device down to but not through the subchondral plate into the adjacent joint. This position is checked on fluoroscopy and length is measured off of the wire, summing the proximal and middle phalanx measurements and choosing the sized implant available. Next the proximal phalanx is broached with the supplied 2.7mm broaching device. The depth of the broach is noted per the ruler on the device (7-10mm depth). The appropriate implant is positioned at the corresponding proximal phalanx reaming depth and placed within the proximal phalanx IM canal. The digit is then grasped and manipulated to place the distal end of the implant into IM canal of the middle phalanx. Once inserted, the implant can be released and the bones are manually compressed across the resection point. Closure consists of re-approximation of the extensor tendon and capsule around the fusion site for extra-medullary stability, and layered closure of the superficial fascia and skin.

Patient Audit

A CPT code audit of 28285 (correction hammertoe, eg. Interphalangeal fusion, partial, or total phalangectomy) from March 1, 2011, to July 15, 2015, was performed. Over that time period, the resulting search yielded 60 patients who had 89 digital surgeries. Patients that had arthroplasty, arthrodesis not performed with the studied device, the studied device plus KW, or isolated DIPJ arthrodesis were excluded. Ultimately, 35 toes in 23 patients had isolated PIPJ fusions using this technique.

Results

The case patient was seen at post-operation weeks 2, 4, and 8. Signs of fusion were noted at week 4 and complete fusion was noted at week 8 radiographically. No loss of fixation was noted at any point. Patient satisfaction was high at discharge.

The CPT audit identified 35 toes that underwent PIPJ arthrodesis using the studied device. Average follow-up was 110 days. There was zero (0%) cases of hardware failure noted. In a single instance (2.8%), the device appeared to have rotated 90 degrees on its long axis, but fixation was still maintained. Two toes (5.7%) were misaligned with  slight medial angulation of the digit. There were zero occurrences of either a superficial or deep incisional infection as defined by the CDC [11]. No patient required revision surgery or a return to the operating room for a complication secondary to the index digital arthrodesis procedure.

Discussion

One of the biggest problems with arthrodesis of the PIPJ can be attributed to the use of EMKW for temporary stabilization across the fusion site until osseous union is achieved. The use of KW for fixation was first described by Taylor in 1940 [1]. Since that time, surgeons have battled against the complications of this technique such as pin-tract infections, digital edema, delayed or non-union of the arthrodesis site due to lack of compression, rotational instability, bent or broken wires, and patient dissatisfaction and apprehension due to the protruding wire and its impending removal [2,10]. External wire exposure infection rates range from 0-18% [1,5,12]. Studies have reported 40% of the wire infections were related to external factors through irritation at the skin-pin interface secondary to trauma and water-contamination [5]. Because of this, Creighton et al (1995) first presented a new technique of the single buried KW in digital fusion [5]. In more recent times, various IMFDs have been manufactured to give the surgeon options of fixation other than the aging gold standard KW. Canales et al (2014) in a recent paper noted 68 IMFDs on the market as of February 1, 2014 [6]. Normal incidence of surgical site infection after foot and ankle surgery has been reported between 1% and 5.3% [13, 14]. Creighton et al (1955) reported an infection rate of 3.5% with his buried KW technique while more recent fusion products have reported similar results ranging from 0%-5% [2,5,7,10]. Our results were similar with a 0% superficial or deep infection rate for the 35 toes at average patient follow-up of 110 days.  No patient at any point or length of follow-up presented for care of digital infection.

One such product for IM digital fusion is the Arrow-LokTM Hybrid implant (Arrowhead Medical Device Technologies, LLC., Collierville, TN) and is the specific implant used by the senior author and reviewed in this article. The implant is made of one solid piece of ASTM F-138 stainless steel, has a core diameter of 1.5mm (0.059”) with a proximal 3-dimensional (3-D) barbed arrow-shaped head 3.0mm by 3.5mm or 2.5mm and distal 3-D arrow-shaped head 3.0mm by 3.5mm. It comes in variable lengths ranging between 13mm and 50mm and in 0° and 10° plantar bend angles [15-17] (Figure 3). There is no special handling or pre-operative storage restriction placing a handling time limitation on implementation [17]. Its use in various clinical situations (PIPJ and DIPJ arthrodesis) as well as surgical tips and tricks have been published on, but to the authors best knowledge no literature exists on loss of correction and infection rates [15,18].

fig3

Figure 3 Intramedullary fusion device comes in straight (top) or 10° angulation (bottom). Key regions include (A)overall length, 13-50-mm; (B) distal tip diameter, 3.5-mm; (C) proximal tip diameter, 2.5-mm or 3.5mm; (D) length of proximal angle segment, variable 6-9-mm; (E) length of proximal angle segment, variable 10-26-mm.

 

The theory of construct of the ArrowLokTM is similar to that of an intramedullary rod (IMR) in fracture care (Figure 4). One of the biggest benefits of the ArrowLokTM device is due to the various available lengths ranging from 13mm to 50mm, the largest identifiable span on the market. Both transfer loads across a break in long bones, whether it be a fusion (ArrowLokTM) or fracture (IMR) site [19]. This IM position is closer to the anatomic axis of the bone and aids to resist bending while the circular round construct resists loads equally in all planes. Mechanical load testing at a quarter of a million cycles at up to 89N showed no signs of wear or fatigue of the ArrowLokTM  or bone [16]. Furthermore, in instances where both PIPJ and DIPJ fusion is needed, one longer device can be used versus two separate devices to be squeezed into a tight space [15]. This results in a location of potential stress riser in the middle phalanx between the distal and proximal ends of the two implants as described in the above situation. This is important when a common results regarding digital fusion (either implanted devices and percutaneous k-wires), the bulk of the non-osseous fusions are made up of fibrous unions which rarely impact the outcome of the surgery and are still considered a surgical success [7,8]. When osseous fusion is not achieved and weaker fibrous tissue fills the fusion interface, much of the strength of the fusion lies in the inherent strength of the implant device.

fig4a fig4ab fig4c

Figure 4 Like an IM rod (left), the ArrowLokTM device (right) garners its strength through its length spanning the osteotomy site to transfer loads and end arrow tips acting as a locking screw, preventing rotation, shortening and gapping, all reasons for failure of fixation.

 

figure-5

Figure 5 DIPJ arthrodesis with the ArrowLokTM device.

The 3-D arrow-ends of the ArrowLokTM act similar to proximal and distal locking screws in IMRs. This secures the device and prevents rotation, compression, shortening, or gapping, resulting in loss of fixation. Compared to a standard 1.6mm  (0.0062”) EMKW, the ArrowLokTM has comparable resistance to bending, increased resistance to pull-out (21x more resistant), and increased resistance to rotational forces (12x more resistant) [16]. These problems are inherent to EMKW use due to the design lacking IM compressive purchase and inability to prevent rotation, leading to potential non-solid fusion and mal- or non-union.

IMRs bending rigidity is based off of diameter and in solid, circular nails, is proportional to nail diameter to the third power [20]. Diameter also affects nail fit with a well fitting nail, reducing movement between the nail and bone, friction between the two maintaining reduction [20]. Reaming with the initial KW and broach help increase this contact relationship. With a 1.5mm core diameter, the ArrowLokTM is a tight fit within the phalangeal canal and increases bending rigidity and construct strength. The long, solid, one-piece design differs from others on the market in not having regions of thinner diameter metal and having two pieces that snap together at the junction of the fusion site – both which lead to sites of potential breakdown [9]. One study demonstrated a 20.7% rate in fracture at internal fixation site using Smart Toe® (Stryker Osteosythesis, Mahwah, NJ) versus 7.1% in 0.062-inch buried IMKW use [9].

Conclusion

The recent literature has demonstrated that utilization of these newer devices like the ArrowLokTM for correction of the hammertoe deformity provide a safe method with low complication rates similar to other products on the market.8 Furthermore, with the decrease and almost elimination of infection rates, despite the higher cost of the implant compared to a KW, the potential for infection complications and the associated cost is avoided. In our retrospective case review, ArrowLokTM showed a lack of hardware failure, zero infection rate, and high patient satisfaction. Due to its available lengths, IMR type construct, and ability to cross two fusion sites at once, this device offers another option for the surgeon in digital fusion.

Conflict of Interest

Dr. Jason R. Miller is a consultant for Arrowhead Medical. Arrowhead Medical Device Technologies had no knowledge or influence in study design, protocol, or data collection related to this report.

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