Artroplastia total de rodilla en pacientes con artritis reumatoide

background: the knee joint is involved in about 90 % of the patients with rheumatoid arthritis (ra). the main purpose of this study was to evaluate the outcome of a total knee arthroplasty (tkr) in patients with rheumatoid arthritis, and analyze the performance of different designs used. methods: 590 tkr were performed between 1997 and 2006, we evaluated 51 (9.5%) arthroplasties in 39 patients with ra diagnosis, followed up for an average of 3.48 years. average age was 59 years. the implants used were 21 monoblock (insall), national make, and thirteen modular, foreign design. (9 pfc "sigma" j & j depuy, warsaw, indiana usa and 4 scorpio stryker howmedical osteonic). the remaining 17 were pfc polyethylene tibial type "all poly" (j & j depuy, warsaw, in. usa). in four patients (8%) femoral and tibial stems were required. results: all patients had a good clinical and radiological outcome, without significant differences between different implants. there were 2 cases of infection (4%), and an extensor mechanism rupture. conclusions: it is an interesting option to use an all-polyethylene tibial component in patients with ra, because it is more economical than modular ones. the surgeon should take into account poor bone quality and the need to insert pins or metallic wedges.