SLR - December 2017 - Christopher L. Clement

A Prospective Study of Four Total Ankle Arthroplasty Implants by Non-Designer Investigators

Reference: Lefrancois T, Younger A, Wing K, Penner M, Dryden P, Wong H, Daniels T, Glazebrook M. A Prospective Study of Four Total Ankle Arthroplasty Implants by Non-Designer Investigators. J Bone Joint Surg Am. 2017 Feb 12;99(4):342–348.

Scientific Literature Review

Reviewed By: Christopher L. Clement, DPM
Residency Program: Southern Arizona VA Health Care System, Tuscon, AZ

Podiatric Relevance: With the number of Total Ankle Arthroplasty (TAA) implants on the rise, it is imperative that podiatric physicians know which TAA implants have better outcomes as reported by patients. These authors present on four common TAA implants and hypothesize that there will be differences in patient outcomes at a minimum of two years.  

Methods: The authors included a total of 451 (75 Agility, 209 Hintegra, 92 Mobility and 75 STAR) TAAs in their study. The mean follow-up time was 4.5 years +/- two years (3.5 years for the Hintegra, 4.2 years for the Mobility, 6.1 years for the Agility and 6.2 years for the STAR group). At annual visits, the patients reported their scores. Scores were obtained from Ankle Osteoarthritis Scale (AOS), physical component summary (PCS) and mental component summary (MCS). Implant selection was decided by the treating surgeon.  
Results: Patients with a Mobility implant showed less mean improvement in the AOS total score, less mean improvement in the AOS pain score and less improvement in the AOS disability score. Mobility implant patients also showed the lowest mean improvement in PCS and MCS scores, but there was a notable overlap of confidence intervals. The number of complete revisions, where the metal components were not retained, was 17 in the Agility group, 17 in the Mobility group, six in the STAR group and 16 in the Hintegra group. The STAR implant was the only implant that required reoperation for an isolated polyethylene liner exchange due to polyethylene liner failure.

Conclusions: Importantly, this study demonstrated acceptable outcomes of the four TAA prostheses. Outcomes from the patient-reported scores were comparable between three of the four prostheses, including Hintegra, STAR and Agility. 

Educational Opportunities