Abstract
Twenty-four replacements were performed in 19 patients (13 female: 6 male), with average age of 33 years (18-40). All had severe polyarticular rheumatoid arthritis. Pre-operatively 12 ankles had no angular deformity, 9 were in valgus and 3 in varus. All had associated hindfoot disease. Some of these patients are part of two larger studies of the Scandinavian Total Ankle Replacement (STAR) and the Buechel-Pappas (BP) replacement. In this group there were 20 STAR and 4 BP replacements. Average follow-up was 62 months (36 to 120). Twenty-one replacements had good pain relief and function. The AOFAS hindfoot score for pain improved from 0 to 36 (max 40) and for function from 25 to 35 (max 60). Three have failed. One ankle had a 25-degree valgus deformity pre-operatively and this recurred and caused failure at 11 months. The second failed at 34 months due to aseptic loosening of the talar component. Both of these were converted to tibio-talo-calcaneal fusions with an intra-medullary nail. The third failure had never provided satisfactory pain relief in spite of appearing satisfactory on clinical and radiological examination. Exploratory surgery was carried out at 36 months but failed to produce an improvement and at 61 months the decision was made to revise the replacement to a fusion. However, due to concurrent health problems, this has not yet been done. We offer replacement to patients with severe polyarticular rheumatoid disease especially if there is a stiff but well aligned hindfoot. In the light of increased experience, we now consider valgus or varus deformity of greater than 20 degrees to be a contra-indication to replacement. This is because the deformity tends to recur leading to pain, loosening and failure.
