Sodhi N, et al. - The National Surgical Quality Improvement Program database was studied to analyze the predictors of longer operative times, predictors of longer lengths-of-stay (LOS) and also to assess the impacts of operative times on LOS in primary total knee arthroplasty. They recorded 93 ± 35 minutes of the mean operative time whereas the mean LOS was 3 ± 3 days. Following were the predictors of longer operative times: young age, male sex, and obesity. Significant associations of age, sex, and body mass index with LOS were also noticed. They recorded an association of increasing 30-minute operative time intervals with increasing LOS. Even after adjusting for patient factors, significant associations of longer operative times were noticed with longer LOS. They reported the greatest effect of operative times on LOS.