Key PointsQuestionWas total knee replacement (TKR) removal from the Medicare inpatient-only (IPO) list in 2018 associated with changes in outcomes in Medicare patients?FindingsIn this cohort study of 37 588 Medicare fee-for-service procedures in a US state administrative database, older, Black, and female patients, as well as patients treated at safety-net hospitals, were less likely to undergo outpatient TKR. When compared with total hip replacements, the IPO policy was not associated with changes in outcomes after TKRs, except for an increase of $770 per encounter.MeaningThese results suggest that there may be disparities in access to outpatient TKRs; TKR removal from the IPO list resulted in a modest increase in cost for surgical encounters but no difference in postoperative health care utilization.