[Total ankle joint replacement]

We evaluated the short- to mid-term results of an unconstrained total ankle prosthesis (S.T.A.R.) with uncemented fixation. Seventy-nine consecutive ankle replacements were performed in 76 patients between 1996 and 2000. The initial diagnosis was posttraumatic osteoarthrosis in 51 cases (64%), primary osteoarthrosis in 14 cases (18%), and systemic joint affection in 14 cases (18%). Although 29 revision operations were necessary, all implants became fix, and no implants have been removed. At the last follow-up control, 38 patients (62%) were very satisfied, 20 patients (33%) were satisfied, and 3 patients (5%) were satisfied with reservations. The obtained range of motion was 35 degrees (range, 15 to 55 degrees), with a maximal plantarflexion of 27 degrees (range, 15 to 45 degrees) and dorsiflexion of 8 degrees (-3 to 20 degrees). The AOFAS-Hindfoot-Score of the 61 patients scored 84 points (range, 51 to 100 points). After settling of the implants within 6 weeks, no migration was noted in any case, and all implants were considered to be stable. The favorable results were considered to be a result of the mechanical properties of the S.T.A.R. total ankle prosthesis that allow for unconstrained motion. The rate of revisions, however, was too high, and it was considered to be a result of the design of tibial and talar component, the tibial fixation and the poor instrumentation. Nevertheless, total ankle replacement was shown to be a viable alternative to ankle arthrodesis. A longer follow-up is, however, mandatory to evaluate the long-term prognosis.