Shah A, et al. - Researchers sought to identify patient-related factors that influence the length of stay (LOS) post-total knee arthroplasty (TKA). In this review, they analyzed 68 eligible studies that were identified from PubMed, Embase, OVID Medline via a search using variants of the terms “total knee arthroplasty” and “length of stay”. The influence of prognostic variables on LOS post-TKA was considered as the primary outcome. Overall 21,494,459 patients with mean age 66.82 years (range, 15 to 95 years), who were undergoing TKA, were examined. Females comprised 63.8% (12,165,160 of 19,060,572 reported) of the study sample. The identified predictors of increased LOS were increased age, female gender, body mass index > 30, non-white race, American Society of Anaesthesiologists > 2, Charlson Comorbidity Index > 0 and preoperative hemoglobin < 130 g/L. With the implementation of perioperative “fast-track” programs, a steady decline in the mean LOS has been reported over the past decades.