Bilateral Versus Unilateral Total Knee Arthroplasty: A Systematic Review and Meta-Analysis of Safety and Functional...

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 length of stay (LOS), ROM, Knee Society Score (KSS), Oxford Knee Score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and physical and mental HRQoL scores. Meta-analyses were conducted using random-effects models. Risk ratios (RRs) and mean differences (MDs) 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 Oxford Knee Score, as well as HRQoL scores, were broadly comparable, with possible improvements in 2-year KSS favoring SBTKA.

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