Total ankle replacement for end-stage ankle arthritis: outcome and indications

Objective To explore the clinical results of total ankle replacements with the Scandinavian Total Ankle Replacement (STAR) prosthesis for end-stage ankle arthritis. Methods Data of 73 cases with end-stage ankle arthritis who received Scandinavian total ankle replacement from January 2005 to May 2013 were retrospectively analyzed. They were 34 males and 39 females, with an average age of 59.6 years old (range, 37-76 years old), average body mass index (BMI) of 25.3 kg/m2 (range, 21.8-28.0 kg/m2). All patients were classified into stage-3 arthritis according to Morrey-Wiedeman. Kofoed, American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and visual analog scale (VAS) were used to evaluate the function of foot and ankle. Patients with a hindfoot deformity below 10° were compared with those who above 10°; and patients above 55 years old were compared with those who below it. Results 5 replacement failed (2 liner ruptured and received replacement; 2 metal components displaced, 1 received TTC fusion and the other underwent revision with inferior tibiofibular joint fusion, the last patient suffered from deep infection and received the STAR removal and secondary fusion) in 73, and the rest were followed up for 12 to 110 months (average, 55.2 months). 59 patients were satisfied with or without reservations. The satisfaction rate was 80.8% (59/73). The pre-op values of AOFAS, Kofoed, VAS and range of motion (ROM) were 46.6±3.5, 43.0±4.7, 8.7±0.7, 34.4°±7.1° and the post-op values were 86.6±4.3, 82.6±4.6, 3.0±1.0, 45.1°±8.2° respectively, and all were significantly improved compared with before. The AOFAS, AOFAS Function and ROM values of patients below 55 years old were 86.1±3.8, 47.0±2.7, 45.7°±7.0°, and the same values of patients above 55 were 86.7±4.6, 46.8±3.1, 44.9°±8.8°. The AOFAS, AOFAS Function and ROM values of patients with above 10° coronal deformity were 86.1±4.7, 47.0±2.7, 43.0°±7.7°, and the same values of patients below 10° were 86.8±4.2, 46.8±3.1, 46.1°±8.2°. There was no difference between the groups. Conclusion The STAR is the preferable surgical treatment option in patients with end-stage ankle arthritis, showing high reliability and effectivity in pain relieving and function improvement. Key words: Ankle joint; Osteoarthritis; Arthroplasty, replacement, ankle