Staged vs simultaneous bilateral unicompartmental knee arthroplasty for clinical outcomes A protocol of systematic review and meta-analysis

Background: Bilateral unicompartmental knee arthroplasty (UKA) can be divided into one or two stages clinically. Compared with staged bilateral UKA, whether simultaneous bilateral UKA has better clinical efficacy remains to be verified. Methods: PubMed, EBSCO, and Web of Science were searched by us for meta-analysis. Studies were considered eligible for inclusion if they included simultaneous and staged UKA. We excluded studies unrelated to the research question, studies in non-selected languages, and studies where the full-text was not available. The data were extracted by two independent investigators, and disagreements were resolved through discussions with a third party. If important data or information about the content of the paper were not available, authors were contacted. Publication bias in studies has been assessed. Meta-analysis was done using Review Manager 5.3. Results: The systematic review and meta-analysis identified 3370 trials, of which 8 studies (963 patients) compared simultaneous with staged bilateral UKA. The meta-analysis showed that the clinical outcomes of simultaneous bilateral UKA goes down in operating time (weighted mean difference [WMD]= -19.34, 95% confidence interval [CI] -22.44 to -16.25, P<.00001), postoperative hemoglobin (Std. mean difference [SMD]= -0.46, 95% CI -0.71 to -0.20, P=.0004), length of stay (LOS) (WMD= - 4.73, 95% CI -6.39 to -3.06, P<.00001), hospital cost (SMD= -5.42, 95% CI -6.54 to -4.30, P<.00001). There were no significant difference in blood transfusion, venous thrombosis, infection, cardiac complications, pulmonary complications, Oxford Knee Score (OKS) between simultaneous and staged bilateral UKA. Conclusion: Simultaneous bilateral UKA can effectively reduce the operating time, LOS, and hospital cost without increasing postoperative complications compared to stage bilateral UKA.