Increased Metal Component Failure with STAR Total Ankle

Abstract

Category: Ankle Arthritis Introduction/Purpose: With the increasing total ankle arthroplasty (TAA) literature, there is a need to further examine the outcomes across a wide variety of implants. The purpose of this study is to review the existing literature and identify trends among current individual TAA implants. Methods: A comprehensive search of MEDLINE for all articles published between 1996 and 2021 was conducted with a minimum two-year mean 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, examining for individual implant survival and component failure. Seventy-three implant groups met inclusion criteria (3rd and 4th generation implants only), composed of STAR (20), Salto (mobile bearing) (10), Salto Talaris (11), Hintegra (8), Zimmer (6), INBONE II (6), INBONE I (4), Infinity (4), Cadence (4). 41 groups (56.2%) were implanted with mobile bearing devices and 32 (43.8%) with fixed bearing implants. In total, 6498 subjects were included with a mean age of 61.77 years and mean BMI of 28.5 kg/m2. At mean follow-up of 62.2 months, the overall reoperation rate was 21.13% and metal component revision rate was 10.16%. Results: Multivariate analysis of all implants, controlling for follow-up duration, found a statistically significant difference in the metal component survival rate (p=.036) and reoperation rate (p=.007) with the STARs TAAs surviving significantly worse and undergoing reoperation at a significantly higher rate than all other implants. There was no statistically significant difference in the rate of metal component revision (p=.768), tibial component failure rate (p=.095), or talar component failure rate (p=.089). Analysis of the Salto Talaris vs Salto found a significant difference in metal component survival rate (Salto=90.68%, Salto Talaris=97.81%; p=.002). Lastly, analysis of the INBONE I vs II implants found INBONE I had a significantly greater rate of revision due to metal component failure (INBONE I=9.8%, INBONE II=3.4%; p=.002). Conclusion: Based on current literature, it appears that the STAR total ankle implant has a statistically significantly lower rate of metal component survival and higher rate of reoperation than the other 3rd and 4th generation implants examined, even when controlling for study follow-up duration. The fixed bearing Salto Talaris had statistically significantly better survival rate than the mobile bearing Salto. These findings are important to physicians when considering implants for total ankle arthroplasty.