Driesman A, et al. - Investigators estimated the patient-reported outcomes (PROs) following TKA among 3 separate cohorts: opiate-naive patients, tramadol exposed subjects and other opiate-exposed cases in this retrospective study. They noticed the average preoperative KOOS scores of 50.4, 49.95, and 48.01 for the naive, tramadol, and narcotic populations, respectively. They observed that the tramadol receiving cases had the least gain in 3 months postoperative KOOS scores, improving on average 12.5 points vs the 19.1 and 20.1 improvements recorded in the narcotic and naive cohorts, respectively.