Carola H, et al. - A systematic review and meta-analysis were intended to investigate the sport habits of patients before and after primary total knee arthroplasty (TKA). Researchers carried out to search PRISMA guidelines, MEDLINE and Scopus for studies reporting the physical activity level and sport habits of patients before and after primary TKA based on validated activity scores or an activity questionnaire. They performed random effect models to pool the mean differences (MD) of activity score values and the difference between pre- and postoperative sport participation rates. Researchers enrolled 25 studies including a total of 6035 TKAs. The level of physical activity significantly elevates following primary TKA according to validated activity scores. According to the UCLA activity score, young patients (≤ 55 years) had the highest gain in physical activity following primary TKA. Sport participation exhibits a slight but non-significant reduce; intermediate and high-impact sports were abandoned to a large degree while participation rates for low-impact sports predominantly elevated. changes were noted in RTS, although approximately 70% resume sport activities.