Comparison of clinical and radiographic results of mobile-bearing total ankle arthroplasty between osteoarthritis and rheumatoid arthritis

Objectives Clinical results of mobile-bearing total ankle arthroplasty (TAA) for rheumatoid arthritis (RA) have been reported, but no studies have compared osteoarthritis (OA) and RA. Clinical and radiographic outcomes after at least 3 years were compared between OA and RA. Methods Eleven ankles with OA and 22 ankles with RA were followed after mobile-bearing TAA (FINE total ankle system). Clinical outcomes were assessed by the American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiographic outcomes were evaluated by the angular position of the implant, radiolucent lines, migration, and subsidence. Operative and postoperative complications were assessed. Results There were no significant differences in clinical outcomes, radiographic outcomes, or complications, except the final follow-up AOFAS total score (OA: 89.4 vs RA: 78.2; p = .044) and pain score (OA: 37.3 vs RA: 30.5; p = .041) at a mean follow-up of 83.4 months. Delayed wound healing occurred in 9.1% in RA and none in OA. Radiolucent lines were observed in 45% of both groups, and implant removal was performed in 9.1% and 18.2% of OA and RA, respectively; there were no significant differences. Conclusions The final follow-up AOFAS total score and pain score were significantly higher in OA after the FINE total ankle system. There was a discrepancy between radiographic abnormalities and implant removal in both OA and RA.