Outcome of knee revisions for osteoarthritis and inflammatory arthritis with postero-stabilized arthroplasties: a mean ten-year follow-up with 90 knee revisions.

PURPOSE: Patients with rheumatoid arthritis (RA) and osteoarthritis (OA) may require revision total knee replacement. Few studies have compared post-operative complications, results and risk of re-revision in RA and OA patients.

MATERIAL AND METHODS: Forty-five RA patients who had undergone revision TKA from 1998 to 2010 were selected and matched with 45 OA patients who had revision during the same period. Results of the use of a revision postero-stabilized implant in osteoarthritis were compared to results of its use in inflammatory arthritis. With a mean follow-up of ten years (range, 5-17 years) we determined differences in comorbidities, risk for peri-operative adverse events, functional and radiological results, and risk of subsequent re-revision, between patients suffering from OA versus RA.

RESULTS: There were higher comorbidities, post-operative (<30 days) adverse events, and mortality at average ten years FU in RA than in OA patients. The mean overall changes in function scores were greater for the RA revision group when compared with the OA revision group. Taking steroids (Cox's regression, p = 0.001), and methotrexate or TNFα blockers (Cox's regression, p = 0.02) were not significant factors for radiolucent lines in RA and for loosening. At average ten years followup, patients with RA undergoing revision TKAs were not more likely to have a re-revision (4 among 45 patients; 9 %) than patients with OA undergoing revision in our department (7 patients; 15 %).

CONCLUSIONS: Similar results for the knee were observed in these two forms of arthritis in spite of the fact that the initial local joint status and general health status are worse in inflammatory rheumatoid arthritis than in "degenerative" osteoarthritis. However, complications were more frequent with RA.