The Short to Mid-Term Outcome of Constrained Condylar Knee and Rotating Hinge Knee for Rheumatoid Arthritis Patients with Severe Knee Deformity and Instability

Abstract

Objectives: This study retrospectively investigated the short-to mid-term outcome of primary legacy constrained condylar knee (LCCK) and rotating hinge knee (RHK) prosthesis in patients with rheumatoid arthritis (RA) having severe varus/valgus deformity, instability and/or bone loss.

Methods: Between January 2000 and December 2016, LCCK and RHK prostheses had been performed for RA amelioration in 16 knees of 12 patients. There was a postoperative follow-up minimum of 1 year. Finally, 14 knees of 10 patients who underwent LCCK and two knees of two patients who underwent RHK were analyzed respectively. The average follow-up duration was 5.7±2.3 years, all patients were female, and the average age and RA duration at the time of surgery was 59.9±9.5 years old and 23.9±13.7 years, respectively. The clinical outcome was analyzed by the Knee Society Score (KSS) in addition to function preoperatively and at the final visit. Imaging outcome was investigated by the femoral tibial angle (FTA), and radiolucent lines both pre- and postoperatively.

Results: KSS knee score (8.0±9.1→95.4±4.3), function score (13.8±16.6→55.9±18.4), and radiographic FTAs (161.7±18.6→173.4±1.1) were improved after operation. Non-progressive radiolucent lines around components were seen in nine knees (56.3%). No infection or reoperation after LCCK and RHK have so far been observed in this study.

Conclusion: Primary LCCK and RHK prosthesis in patients with RA were achieved with excellent short-to mid-term clinical and radiographic results.