Comparison of the efficacy of total knee arthroplasty with different prostheses for knee valgus

Abstract

Objective To compare the efficacy of fixed bearing(FB) and rotating bearing(RB) in total knee arthroplasty (TKA) for knee valgus. Methods Data of 203 cases with valgus knee deformity who had undergone TKA procedure from January 2007 to December 2013 were retrospectively analyzed. 181 cases were primary joint replacement. They were divided into FB group and RB group. 168 patients (168 knees) were followed-up for more than 2 years. 83 cases (83 knees) were in FB group, and 85 cases (85knees) were in RB group. There were 57 males and 111 females, aged from 40 to 79 years, with an average age of 59.3±7.2 years. Among them, 153 cases were osteoarthritis and 15 cases were rheumatoid arthritis. Activities of the knee, tibiofemoral angle on X-ray, Hospital for Special Surgery (Hospital for Special Surgery, HSS) knee score and the SF-36 scale scores were recorded before surgery and at the final follow-up. Results All patients were followed up for 24 to 84 months (average, 37.4 months). The average knee activities of the fixed bearing and rotating mobile bearing were from 72.8°±13.1°and 71.2°±12.8° before surgery to 106.5°±9.8°and 115.4°±7.9° at final follow-up. The average tibiofemoral angle on X-ray decreased from 16.8°±5.3° and 15.2°±4.7° preoperatively to 5.6°±2.3 and 5.2°±2.1° at the final follow-up. The HSS knee score improved from 47.5±7.1 points and 49.6±8.9 points to 89.1±4.6 points and 90.2±5.3 points at final follow-up. The SF-36 scale scores improved from 52.3±15.4 points and 50.1±17.9 points to 81.6±12.3 points and 82.2±14.5 points at the final follow-up. At the latest follow-up, except the Range of motion, there were no statistically significant in any other indicator between two groups. Two cases appeared postoperative deep venous thrombosis symptoms. One case had joint stiffness early, and the symptoms improved after strengthen functional exercise. No infections, delayed knee instability, implant loosening or subsidence was found during the follow-up. Conclusion For patients with mild to moderate knee valgus, both fixed and rotating bearing with same soft tissue balance technique can improve the knee function and correct the valgus deformity, and the recent results are satisfactory. Key words: Genu Valgum; Arthroplasty, replacement, knee; Prostheses and implants