Abram SGF, Yusuf B, Alvand A, et al. - This study was undertaken to investigate the correlation between manipulation under anesthetic (MUA) after primary knee arthroplasty and subsequent revision surgery. Researchers distinguished patients who had undergone primary knee arthroplasty from April 2011 to April 2016 with minimum 1-year follow-up to April 2017 from the national hospital episode statistics for England. Individuals undergoing MUA within 1 year to the same knee were distinguished, characterizing the populations for the MUA and non-MUA cohorts. They applied a Cox proportional hazards model to ascertain the hazard for revision, adjusting for type of primary arthroplasty, gender, age group, year, comorbidity index, obesity, regional deprivation, rurality, and ethnicity. The study included a sum of 309,650 primary arthroplasty cases (309,650 patients). Individuals who had undergone MUA within 1 year of primary arthroplasty were at a 5-fold increased risk of subsequent revision even after excluding cases of infection or fracture. Future evaluation of the etiology of stiffness after primary knee arthroplasty and the optimal treatment options to improve results is verified.