抄録
Objective: The low contact stress (LCS) mobile bearing knee arthroplasty (DePuy Orthopaedics Inc, Warsaw, Indiana) has been in extensive use. Most of the results have been reported in predominantly osteoarthritis (OA) patients. There have been only a few studies with respect to the performance in patients with rheumatoid arthritis (RA) over an intermediate to long-term period. The objective of this retrospective study was to report 5 to 20 year clinical results in such patients.
Methods: Between July 1988 and June 2013, the senior author (T.Y.) performed 143 primary LCS mobile bearing total knee arthroplasties (TKAs) in 107 patients with RA. The mean age of the patients at the time of the surgery was 68 years.
Results: More than five years after the procedure, 64 patients (87 knees) were alive and 13 patients had died. Fifty two (56 knees) of 64 patients (87 knees) were followed clinically and radiographically. We revised two knees during the 2 to 14 year period of follow-up. One patient had a revision using a ceramic implant (KU-4) because of metal allergy. The other patient underwent an additional patellar replacement because of anterior knee pain 14 years after the primary surgery. The mean clinical Japanese Orthopedic Association score was 85 (70 to 95), at final follow-up and the mean passive range of motion was 129° (95° to 155°). The survival rate was 96% at 91 months. No radiological evidence of loosening was noted in 27 cementless knees. Thirty-three knees had no replacement of the patella. Fourteen patients had surgery to other joints in addition to their TKA with other arthroplasties in seven and treatment of seven fractures.
Conclusion: We found good clinical results for the LCS mobile knee arthroplasty in patients with RA, which were similar as the results in patients with OA.
