Anton H Hosman1, Rhett B Mason, Toni Hobbs, Alastair G Rothwell. 1. Department of Orthopedic Surgery and Musculoskeletal Medicine, Christchurch School of Medicine and Health Sciences, University of Otago, Christchurch, New Zealand. antonhosman@gmail.com
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.
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.
Authors: Alexej Barg; Matthias D Wimmer; Martin Wiewiorski; Dieter C Wirtz; Geert I Pagenstert; Victor Valderrabano Journal: Dtsch Arztebl Int Date: 2015-03-13 Impact factor: 5.594