One-stage bilateral unicompartmental knee arthroplasty is a suitable option vs. the two-stage approach: a meta-analysis.

To compare one-stage vs. two-stage bilateral unicondylar knee arthroplasty (UKA) in terms of complications, mortality, reinterventions, transfusion rate, days to discharge, and outcomes for the treatment of bilateral mono-compartmental knee osteoarthritis.A systematic review was performed in the PubMed, Web of Science, and Cochrane databases up to February 2021. Randomized controlled trials, case-control studies, and case series describing the use of bilateral UKA were retrieved. A meta-analysis was performed on complications, mortality, reinterventions, transfusion rate, and days to discharge comparing one-stage vs. two-stage replacement, and outcomes were also reported. Assessment of risk of bias and quality of evidence was performed with the Newcastle-Ottawa Scale.Fifteen articles were included on 1451 patients who underwent bilateral UKA (44.9% men, 55.1% women, mean age 66 years). The systematic review documented, for bilateral one-stage UKA: 2.6% major and 5.4% minor complication rates, 0.5% mortality, 1.9% reintervention, 4.1% transfusion rates, and 4.5 mean days to discharge. No studies reported functional differences. The meta-analysis did not find differences for major complications, minor complications, mortality, reintervention, transfusion rates, or days to discharge versus two-stage bilateral procedures. The operative time was 112.3 vs. 125.4 minutes for one-stage and two-stage surgeries, respectively. The overall quality of the retrieved studies was high.Bilateral single-stage UKA is a safe procedure, with a few complications, and overall positive clinical results. No differences were found in terms of complications, mortality, reinterventions, transfusion rate, and days to discharge in comparison with the two-stage approach. Cite this article: 2021;6:1063-1072. DOI: 10.1302/2058-5241.6.210047.