Khow YZ, Goh GS, Chen JY, et al. - This study was undertaken to investigate the prevalence of patients who lost or gained weight, ascertain whether postoperative weight change influences functional outcome, and distinguish predictors of weight change after simultaneous-bilateral total knee arthroplasty (SB-TKA). Researchers examined prospectively collected registry data of 560 patients who had undergone SB-TKA. They applied the Chi-square test to compare functional outcomes between groups. Predictors for postoperative weight changes were assessed by multivariable logistic regression. After SB-TKA, up to 41% of patients experience significant weight changes. The outcomes revealed that the older individuals with higher preoperative BMI were more likely to gain weight, while higher preoperative BMI with more comorbidities were less likely to lose weight following SB-TKA, nevertheless, postoperative weight changes do not seem to influence functional outcomes.