Comparison of Clinical Outcomes and Safety of Single-stage Bilateral and Unilateral Unicompartmental Knee Arthroplasty

Objective: To evaluate the effectiveness and safety of bilateral Oxford medial unicompartmental knee arthroplasty (UKA) in the patients under a single anesthetic procedure. Methods: Between October 2013 and December 2015, 225 knees of 181 (age 67.5 years) patients with at least two years of follow-up were evaluated. They were divided into two groups as unilateral group (group 1, n=137) and one-stage simultaneous bilateral group (group 2, n=44) for the comparisons. The outcome parameters were femoral and tibial component positions measured on the full-length radiographs, clinical outcomes using Oxford Knee Score (OKS), International Knee Documentation Committee Score (IKDC), patient reported satisfaction and complications. Results: Between the groups, the mean follow-up periods (p=0.125), age (p=0.447), preoperative body mass index (p=0.288), OKS (p=0.314) and IKDC (p=0.127) scores were not significantly different. Postoperatively, the mean flexion of the femoral component (p=0.544), posterior slope (p=0.511), varus-valgus angulation of the tibial components (p=0.358) were statistically similar between groups. Although the mean varus-valgus angulation of the femoral components (p=0.033) was statistically different between groups, the difference was too small to make clinical significance. The mean postoperative OKS (p=0.272) and IKDC (p=0.106) were similar between the groups. In group 1, 21 (16.0%) patients reported excellent, 91 (69.5%) good and 4 (3.1%) moderate satisfaction. Fifteen (11.5%) patients reported non-satisfaction. In group 2, patients reported excellent satisfaction in 20 (24.4%) knees, good in 50 (61.0%) knees patients moderate in 2 (2.4%) knees. Patients reported non-satisfaction in 10 (12.2%) knees (p>0.05). Eight (5.8%) complications in group 1 and, 3 (3.4%) complications in group 2 were observed. The number of complications was not statistically different between the groups (p=0.535). Conclusion: One-stage simultaneous bilateral Oxford medial UKA is a safe and effective method with acceptable complication rates compared to unilateral surgery. Keywords: Unicondillar, unicompartmental, knee, artrhroplasty, bilateral