Long-term follow-up of the Conaxial (Beck-Steffee) total ankle arthroplasty

Between 1975 and 1977, 30 patients with traumatic arthritis or rheumatoid arthritis underwent 36 Conaxial (Beck-Steffee) ankle replacements (DePuy, Warsaw, IN). Thirty-two were primary replacements and four were revisions of previous ankle arthroplasties. Twelve patients had traumatic osteoarthritis and 18 patients had rheumatoid arthritis. The average age at operation of patients with rheumatoid arthritis was 61 years (range 28-67 years) and with osteoarthritis was 52.9 years (range 32-72 years). The average follow-up was 10.8 years, with a range of 10 to 13 years. Early postoperative complications included wound dehiscence in 39% of patients (14 patients), deep wound infection in 6%, fractures of the medial or lateral malleolus in 22%, and painful talofibular impingement in 14%. At 2-year follow-up, 27% of the ankle replacements were loose. Sixty percent were loose at 5 years and 90% were loose at the 10-year follow-up. Ten patients had implant removal and attempted fusion. Six, or 60%, fused in an average of 5 months. Of those patients who achieved ankle fusion, four had internal fixation and iliac crest autografting, one had a Charnley compression apparatus with allograft bone, and one had internal fixation with allograft bone. The constrained Conaxial ankle replacement should no longer be implanted because of a 90% loosening rate at 10 years and an overall complication rate of 60%.