A 27-year Meta-analysis of Ankle Arthroplasty

Abstract

Category: Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty is an alternative to ankle arthrodesis for the treatment of end-stage arthritis while maintaining greater ankle motion and functionality. Early generation implants had unacceptably high complication rates. However, increasing surgical experience and newer third-generation designs have the potential to offer better outcomes. A previous systematic review reported results from studies published between 1990 and 2005, focusing on second-generation implants. We performed a systematic review of the literature addressing the intermediate-long-term outcomes of interest in total ankle arthroplasty studies published since 2006, and we compared our findings to those from earlier generation implants. Methods: A comprehensive search of MEDLINE for all articles published from 3/25/2006 to 2/1/2017 was conducted with a minimum two-year follow-up. Two reviewers evaluated each study to determine whether it was eligible for inclusion and abstracted the data of interest. Meta-analytic pooling of group results across studies was performed. The analysis focused on third-generation ankle implants. Results: The previous systematic review identified 10 studies (n=852), whereas we identified 40 studies (n=4835). The prior study showed a five and ten-year survival rate of 78% and 77%, respectively; respective rates were 86% (p=0.001) and 76% (p=0.53) in ours and similar to the previous study. The revision rate following TAR was 7% in the earlier review (loosening/subsidence, 28%). In ours, the revision rate following TAR was 9.6% (p=0.10) (component loosening, 37%); 3.4% (p=0.02) of ankles were converted to arthrodesis. The mean post-operative Ankle-Hindfoot score was 78.2 points in the prior review and 80.1 (p=0.20) points for ours. There is significant (p<0.0001) heterogeneity (I2=92.94%) between the studies; a meta-analysis of proportions showed that 81.6%of subjects had good outcomes while 46.6% had an excellent outcome. Conclusion: Based on these findings, the outcomes for third-generation total ankle arthroplasty have no significant differences in survival rates when compared to second-generation implants. However, functional scores, range of motion, and overall patient outcomes were significantly higher in the third-generation implants. However, data from early generation studies were sparse in comparison, so direct comparative studies are needed to strengthen this conclusion.