[Posterior capsule releasing in total knee arthroplasty for patients with rheumatoid arthritis with stiff knees in flexion].

Objective: To investigate the correct method of bone resection and posterior capsular soft tissue releasing in total knee arthroplasty (TKA) for the patients with rheumatoid arthritis with stiff knee in flexion.

Methods: From November 2009 to January 2012,15 patients with rheumatoid arthritis with stiff knee in flexion underwent primary TKA and releasing of the posterior soft tissues. There were 7 males and 8 females,aged 22 to 75 years old (58.7 years old on average). The preoperative range of movement(ROM) was (3.2 ± 1.7)°. According to Knee Society score (KSS) criterion, the preoperative clinical score was 23.3 ± 12.5 and functional score was 35.2 ± 9.8. Based on the correct osteotomy, effective releasing of posterior structures was used for different degrees of flexion contracture during the TKA procedure.

Results: All the patients were followed up, and the average duration was 2.3 years (1.6 to 3 years). At the latest follow-up,the KSS clinical score was 81.7 ± 6.5 and functional score was 82.8 ± 9.3. The flexion and extension ROM of the knee joint was (103.5 ± 13.1). Three knees remained 50 flexion contracture deformity, but the function of the affect knees was good.

Conclusion: The effective releasing of the soft tissue of posterior capsule is a major management for correction of the flexion contracture in TKA. The correct releasing of posterior structure can not only achieve fundamental gap of TKA but also effectively avoid bone over-resection.