両側対側全膝関節置換術 vs 片側全膝関節置換術：安全性および機能的転帰に関する系統的レビューおよびメタアナリシス

Total knee arthroplasty (TKA) is a common procedure for end-stage knee osteoarthritis. The comparative safety and functional outcomes of simultaneous bilateral TKA (SBTKA) versus unilateral TKA (UTKA) remain uncertain. This systematic review evaluated the complication rate, range of motion (ROM), functional recovery, and health-related quality of life (HRQoL) in patients who underwent SBTKA or UTKA.

We performed a comprehensive literature search identifying 52 studies, including 5,859,125 patients who underwent SBTKA or UTKA. Outcomes assessed included complications, mortality, and readmission rates from the in-hospital period to 90 days, as well as lengths of stay (LOS), ROM, Knee Society Score (KSS), Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and physical and mental HRQoL scores. Meta-analyses were conducted using random-effects models. Risk ratios (RR) and mean differences (MD) were calculated for dichotomous and continuous outcomes, respectively.

Patients who underwent SBTKA had a longer LOS (mean 0.8 days; 95% confidence interval [CI]: 0.3 to 1.3; P = 0.003) and higher complication rates (RR 1.42; 95% CI: 1.21 to 1.67; P < 0.001) compared with patients who underwent UTKA. Mortality (RR 1.12; 95% CI: 0.79 to 1.59; P = 0.55) and readmission (RR 1.13; 95% CI: 0.91 to 1.41; P = 0.29) were similar between groups. Functional outcomes, including ROM, KSS, and OKS, as well as HRQoL scores, were broadly comparable, with possible improvements in two-year KSS favoring SBTKA.

Compared with UTKA, SBTKA is associated with a higher risk of complications and a longer LOS, while functional outcomes, range of motion, and health-related quality of life appear comparable between the two groups. Further high-quality studies are needed to clarify long-term outcomes and guide patient selection.