Long-Term Clinical and Radiological Outcomes of Cementless Total Knee Arthroplasty in Patients with Rheumatoid Arthritis.

Background: Total knee arthroplasty (TKA) is an established treatment for end-stage rheumatoid arthritis (RA). Although cemented fixation has traditionally been preferred because of concerns regarding poor bone quality, advances in implant design and osseointegration have renewed interest in cementless fixation. This study evaluated the long-term clinical and radiological outcomes of cementless TKA in patients with RA. Methods: A retrospective single-center study included adult patients with RA who underwent primary cementless TKA between 2004 and 2021 using the same cruciate retaining implant. Clinical outcomes were assessed using range of motion (ROM), Visual Analog Scale (VAS), Oxford Knee Score (OKS), and patient satisfaction. Radiographic evaluation assessed implant fixation, while implant survivorship was analyzed using bilateral clustering via a Marginal Cox model analysis. Results: Seventy-five cementless TKAs performed in 52 patients were analyzed after a mean clinical follow-up of 10.8 ± 3.8 years. Mean ROM was 101° ± 26.5°, mean VAS score was 0.88 ± 1.84, and mean OKS was 40.3 ± 7.1. Overall, patients were satisfied or very satisfied in 89.6% of implants. Radiographic assessment showed no evidence of progressive radiolucent lines, osteolysis, implant subsidence, aseptic loosening, or malalignment. Only one revision was required because of periprosthetic joint infection, resulting in an implant survivorship of 98.3% at long-term follow-up. Conclusions: Cementless TKA demonstrated excellent long-term implant survival, durable radiographic fixation, and favorable clinical and functional outcomes in patients with rheumatoid arthritis. These findings support modern cementless fixation as a reliable and effective alternative to cemented TKA in carefully selected RA patients.