In RA patients with a very aggressive disease, pathological changes in the knee occur in 90% of cases in the end-stage period. These changes are often accompanied by severe deformities, such as flexion contracture, valgus deformity, and more rarely varus deformity. In order to provide soft tissue balance, these deformities require additional surgery before implantation of the prosthesis. In this article the authors describe different methods, depending on the nature of the deformities, such as posterior release and lateral soft-tissue release, which should be done in successive stages. The problem of the patella and loss of bone stock for reconstruction is briefly discussed.