Comparison of unicompartmental knee arthroplasty and total knee arthroplasty in the treatment of unicompartmental osteoarthritis: a meta-analysis

Background It is not clear whether unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA) leads to better outcomes in the treatment of unicompartmental knee osteoarthritis. The purpose of our meta-analysis was to compare the clinical outcomes of UKA and TKA in the treatment of unicompartmental knee osteoarthritis. Methods We searched all major medical databases for randomized controlled trials or well-designed quasi-randomized trials that compared UKA with TKA in the treatment of unicompartmental knee osteoarthritis and conducted a meta-analysis with RevMan software (The Cochrane Collaboration, Oxford, England) to compare the clinical outcomes after assessment of study quality and heterogeneity. Results The results of the meta-analysis indicated that UKA required more revisions in the group with follow-up of less than 5 years after operation (risk ratio [RR] = 3.47; 95% confidence interval [CI]: 1.23-9.77; P = 0.02), but the difference was not significant after 5 years (RR = 0.87; 95% CI: 0.29-2.60; P = 0.81). Patients who underwent UKA had better range of motion (weighted mean difference [WMD] = 6.431; 95% CI: 3.46-9.40; P<0.001) and fewer complications (RR = 0.20; 95% CI: 0.08-0.52; P = 0.0009) than those who had TKA. Knee Society Scores were similar between the groups (WMD = 0.16; 95% CI: -2.12-2.45; P = 0.89), but functional scores were higher for the UKA than TKA group (WMD = 1.96; 95% CI: 0.15-3.78; P = 0.03). Conclusions UKA provided better postoperative function and fewer complications than TKA. UKA called for more revisions in the group with follow-up of 5 years or less (follow up 0-5 years), but the difference was not significant after 5 years (follow-up 5-15 years).