A New Zealand national joint registry review of 202 total ankle replacements followed for up to 6 years

Abstract

Background and purpose There have been few reports of large series of ankle replacements. The aim of this study was to document and evaluate the early results of a nationwide series of total ankle replacements (TARs) performed using second-and third-generation implants.Methods Records of total ankle replacements performed between February 2000 and November 2005 were retrieved from the New Zealand National Joint Registry and retrospectively reviewed at a mean of 28 months after the primary procedure. At 6 months post surgery, patient scores were generated from questionnaires. Comparisons between patient scores and categorical variables were made using ANOVA. Regression analyses using Cox proportional-hazards modeling were performed to determine predictors of failure. A Kaplan-Meier survivorship curve was used to describe the rate of prosthetic survival.Results 202 total ankle replacements were performed in 183 patients. 14 prostheses (7%) failed. The overall cumulative 5-year failure-free rate was 86%. An unfavorable patient score at 6 months after the initial procedure turned out to be a good predictor of subsequent failure. The cumulative 5-year failure-free rate was 65% at 5 years for patients with an unfavorable score, and 95% for those who had a favorable patient score. Each 1-point increase in the patient score (i.e. poorer outcome) corresponded to a 5% relative increase in the risk of failure (p < 0.05). In addition, longer operative time for the primary procedure was found in the group of TARs that subsequently failed (p < 0.05).Interpretation The National Joint Registry appears to be a useful tool for monitoring the trends in TAR surgery.

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).…”

“…We believe expansion of the clinical trial is justified, but longer followup with larger numbers of patients is required to assess the new TAA in the longer term. Years after operation Percentage not revised Henricson et al 2007 [24] Fevang et al 2007 [15] SooHoo et al 2007 [48] Hosman et al 2007 [26] Anderson et al 2003 [3] Wood & Deakin 2003 [54] Current study Fig. 7 The graph shows a trend of cumulative survival rates from similar studies; the current series shows the best results in the period analyzed.…”

“…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].…”

The Scandinavian Total Ankle Replacement: Survivorship at 5 and 8 Years Comparable to Other Series

“…Second-generation designs have been mostly uncemented with either a fixed or mobile polyethylene bearing and better results [4]. Second-generation 5-year survival rates range from 78% to 93% and the 10-year survival from 76% to 80% [8,11,13,21]. The STAR prosthesis (LINK1 STAR Scandinavian Total Ankle Replacement, Waldemar Link, Hamburg, Germany) is one such second-generation, three-component mobile-bearing uncemented device currently in use in Europe and recently granted conditional approval by the FDA in the United States [18].…”