Introduction: Although the literature has confirmed the short and intermediate term efficacy of three-component mobile-bearing total ankle arthroplasty (TAA), the development of progressive periprosthetic bone abnormalities threatens the intermediate and long term survival of these implants. The aim of this study was to evaluate whether TAA quality requirements were met and analyze radiological changes in arthroplasties performed by members of the French Western Orthopedics Society.
Materials and methods: This retrospective multicenter study included 173 patients who underwent three-component mobile-bearing arthroplasty between 1997 and 2010 in eight centers in western France. The etiology was osteoarthritis (OA) in 78% of cases and rheumatoid arthropathy in 13% of cases. The radiographic assessment included preoperative and final postoperative standing anteroposterior (AP) and lateral view radiographs. Radiographs were reviewed for ankle alignment, improper implant positions, and periprosthetic bone anomalies. Intraprosthetic range of motion was evaluated in 111 cases on dynamic radiographs.
Results: Mean follow-up was 34 months (± 5). Fifteen percent of the cases presented implant malposition. Alignment was normal in 76% of cases. Intraprosthetic range of motion was 20.5° (± 3) in the cases that were evaluated. Bone cysts were observed in 33% of cases, radioluncencies in 72%, ossifications in 39%, migration of the tibial component in 5% and migration of the talar component in 27%. The latter were correlated to a range of motion of less than 15°. Additional surgery was necessary in 8% of cases to revise implants and/or for conversion to arthrodesis.
Discussion: The high rate of radiolucencies and bone cysts at a mean follow-up of 2.8 years is of concern and these arthroplasties should be closely monitored. Stiff ankles seemed to be at a higher risk for subsidence.
Level of evidence: IV - Retrospective study.
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