Ankle fusion as a treatment option for end-stage ankle osteoarthritis (OA) has been reported as the “gold standard”.1 Most patients who undergo ankle fusion experience significant early pain relief postoperatively.1-3 However, many patients with an ankle fusion develop long-term degenerative changes in adjacent joints.2,4 This progressive development of degenerative changes may require addition fusion surgery, eg, subtalar fusion.5
A nonunion or malunion of an ankle fusion is an uncommon but severe post-surgical complication.1 In patients with painful nonunited or malunited ankle arthrodesis, takedown of the arthrodesis and subsequent implantation of a total ankle prosthesis may be a treatment option.
Newton performed three total ankle replacements (TARs) using the Newton Ankle Implant in patients with nonunion of a prior ankle fusion.6,7 The initial ankle fusion was performed because of avascular necrosis of the talus. In one patient, four unsuccessful fusion attempts were performed. All three implants failed, requiring one prosthesis revision and two lower leg amputations. Therefore, the author stated that TAR should not be performed in patients with a previously failed ankle fusion.6,7
In 2004, Greisberg et al published a retrospective study of 23 procedures in 22 patients to review takedown of ankle fusion and conversion to TAR using the Agility prosthesis.8 At a mean follow-up of 30 months, 18 patients (19 ankles) were available for clinical and radiological review. In three patients, a lower leg amputation was performed because of significant residual pain. In the remaining 16 ankles, a significant functional improvement was detected as assessed by the AOFAS score. Thus, in this study a remarkable rate of postoperative complications with a failure rate of 42.1% was reported. However, the authors suggested that this procedure is a viable alternative to amputation, primarily in patients with a definable source of pain and who have not had previous malleolar resection during the initial ankle fusion.8
Between 1999 and 2004, Hintermann et al performed 29 conversions of painful ankle fusion to TAR in 27 patients using the HINTEGRA TAR.9,10 At a mean follow up of 56 months, most patients (82.7%) were satisfied with results and showed significant pain relief and functional improvement as assessed using VAS and AOFAS scores, respectively. One ankle had to be revised because of persistent pain and significant loosening of the talar component. All but one tibial component were stable; the talar component was found to have migrated in four ankles but was asymptomatic in two of them.9,10
Atkinson et al published a case report addressing clinical outcome and gait analysis following conversion of tibiotalocalcaneal fusion to TAR using HINTEGRA implants.11 Two years after the conversion to TAR, the patient was subjectively delighted with her increased mobility and functional improvement. The objective results of her gait analysis, which included comfortable walking pace, stride length, and cadence, showed a trend toward normalization of gait mechanics.11
In 2010, Barg and Hintermann published the detailed technique of this procedure.12 The absolute contraindications for the procedure include:
* Non-manageable hindfoot deformity
* Highly comprised soft tissues and large scars on the medial side
* Severe vascular and/or neurological deficiency
* Active osteomyelitis and/or deep infection
* Chronic pain syndrome existing over years
* Neuropathic disorders (Charcot arthropathy).12
This procedure may be used with some restrictions (relative contraindications) in the following cases:
* Previous fibulectomy
* Long-standing immobilization
* More than 3 cm shortening of the affected leg
* High demands for physical and sports activities
* Diabetic syndrome without polyneuropathy.12
In conclusion, current studies show favorable mid-term results after conversion to TAR in patients with painful ankle arthrodesis.9-11 However, this procedure is technically more demanding that primary TAR and should be limited to foot and ankle surgeons with adequate experience in primary TAR. Additionally, careful preoperative planning and selection of patients are very important factors in achieving a good clinical outcome.
- Nihal,A., Gellman,R.E., Embil,J.M., and Trepman,E.: Ankle arthrodesis. Foot Ankle Surg, 14:1-10, 2008.
- Coester,L.M., Saltzman,C.L., Leupold,J., and Pontarelli,W.: Long-term results following ankle arthrodesis for post-traumatic arthritis. J Bone Joint Surg Am, 83-A:219-228, 2001.
- Plaass,C., Knupp,M., Barg,A., and Hintermann,B.: Anterior double plating for rigid fixation of isolated tibiotalar arthrodesis. Foot Ankle Int, 30:631-639, 2009.
- Fuchs,S., Sandmann,C., Skwara,A., and Chylarecki,C.: Quality of life 20 years after arthrodesis of the ankle. A study of adjacent joints. J Bone Joint Surg Br, 85:994-998, 2003.
- SooHoo,N.F., Zingmond,D.S., and Ko,C.Y.: Comparison of reoperation rates following ankle arthrodesis and total ankle arthroplasty. J Bone Joint Surg Am, 89:2143-2149, 2007.
- Newton,S.E., III: Total ankle arthroplasty. Clinical study of fifty cases. J Bone Joint Surg Am, 64:104-111, 1982.
- Newton,S.E.: An artificial ankle joint. Clin Orthop Relat Res, 142:141-145, 1979.
- Greisberg,J., Assal,M., Flueckiger,G., and Hansen,S.T., Jr.: Takedown of ankle fusion and conversion to total ankle replacement. Clin Orthop Relat Res, 424:80-88, 2004.
- Hintermann,B., Barg,A., Knupp,M., and Valderrabano,V.: Conversion of painful ankle arthrodesis to total ankle arthroplasty. J Bone Joint Surg Am, 91:850-858, 2009.
- Hintermann,B., Barg,A., Knupp,M., and Valderrabano,V.: Conversion of painful ankle arthrodesis to total ankle arthroplasty. Surgical technique. J Bone Joint Surg Am, 92 Suppl 1 Pt 1:55-66, 2010.
- Atkinson,H.D., Daniels,T.R., Klejman,S., Pinsker,E., Houck,J.R., and Singer,S.: Pre- and postoperative gait analysis following conversion of tibiotalocalcaneal fusion to total ankle arthroplasty. Foot Ankle Int, 31:927-932, 2010.
- Barg,A. and Hintermann,B.: Takedown of painful ankle fusion and total ankle replacement using a 3-component ankle prosthesis. Tech Foot & Ankle, 9:190-198, 2010.