The Swedish Ankle Arthroplasty Register: An analysis of 531 arthroplasties between 1993 and 2005

Abstract

Background Whether or not ankles can be replaced with reasonable safety has been the subject of debate. We present the results of a nationwide series of total ankle arthroplasties.Patients and methods All Swedish hospitals that implant or have implanted modern three-component ankle prostheses reported demographic data and date of index and revision surgery to a central register. After the data had been introduced into a database, prosthetic survival rates with exchange or permanent extraction of components as endpoint were calculated.Results Of the 531 prostheses implanted, 101 had been revised by June 15, 2006. The overall survival rate at 5 years was 0.78 (95%CI: 0.74-0.82). For the three surgeons who had inserted the majority of the STAR ankles, the survival rates became significantly higher after the first 30 cases had been performed and was estimated to be 0.86 (0.80-0.93) at 5 years. Lower age at index surgery implied increased risk of revision whereas diagnosis or gender did not.Interpretation Ankle replacement is a valuable alternative to arthrodesis. However, replacing an ankle is a demanding procedure and the survival is not comparable to that after hip or knee replacement. It is obvious that with increasing experience, the results-including prosthetic survival-will improve.

Total Ankle Replacement Compatible with Ligament Function Produces Mobility, Good Clinical Scores, and Low Complication Rates: An Early Clinical Assessment

“…Our data with 51 ankles at risk during the first year and a 4-year survival rate of 97.2% suggest few postoperative complications requiring component removal in contrast to reports from the registries [15,24,26] or from experienced surgeons [3,6,7,25,30,40,42,[51][52][53] (Fig. 7).…”

“…Third, we had a large number (75%) of posttraumatic osteoarthritic ankles compared with only 28% on average in a recent metaanalysis [48]. Another study suggests patients with posttraumatic osteoarthritis have higher complication and revision rates than patients with rheumatoid or primary osteoarthritis [24], and therefore this bias might reinforce the value of corresponding rates from the current study. Fourth, we report the range of foot-to-shank rather than that of the tibiotalar joint.…”

“…In one series of 122 cases with 1 to 3 years followup [25], revisions have occurred at 2, 5, 8, 9, 10, 11, 12, and 21 months. Our current trial has not reproduced the experience of the Swedish TAA registry of a higher failure rate among the first 30 cases contributed by individual surgeons [24].…”

“…The Kaplan-Meier method was used to calculate cumulative survival rates and Peto's method to calculate the 95% confidence limits for those rates [4]. The survival rates were compared with those in published series [3,15,24,26,46,52], particularly those from national registries [15,24,26], and the AOFAS scores, complication rates, and range of flexion results with Stengel's meta-analysis [48]. We used the regression utility in Microsoft Excel 2003 (Microsoft Inc, Redmond, WA, USA) to determine the statistical significance of the relationship between range of ankle flexion and bearing movement.…”

“…Recent publications from the Swedish [24], Norwegian [15], and New Zealand [26] registries have revealed a steady annual revision rate of TAA (with removal of components) of 2% to 3%, whereas a similar population study from California reported a 4.6% annual revision rate [46]. One meta-analysis with more than 1000 cases showed limited improvement in range of flexion, pain, function, and alignment, and a high rate of other complications [48].…”