The Journal of Arthroplasty, Volume 35, Issue 1, 7 - 11

Patient Outcomes Following Total Joint Replacement Surgery: A Comparison of Hospitals and Ambulatory Surgery Centers

Carey, Kathleen et al.
Hip Knee


For several years, many orthopedic surgeons have been performing total joint replacements in hospital outpatient departments (HOPDs) and more recently in ambulatory surgery centers (ASCs). In a recent shift, the Centers for Medicare and Medicaid Services began reimbursing for total knee replacement surgery in HOPDs. Some observers have expressed concerns over patient safety for the Medicare population particularly if Centers for Medicare and Medicaid Services extends the policy to include total hip replacement surgery and coverage in ASCs.


This study used a large claims database of non-Medicare patients to examine inpatient and outpatient total knee replacement and total hip replacement surgery performed on a near-elderly population during 2014-2016. We applied propensity score methods to match inpatients with ASC patients and HOPD patients with ASC patients adjusting for risk using the HHS Hierarchical Condition Categories risk adjustment model. We conducted statistical tests comparing clinical outcomes across the 3 settings and examined relative costs.


Readmissions, postsurgical complications, and payments were lower for outpatients than for inpatients. Within outpatient settings, readmissions and postsurgical complications were lower in ASCs than in HOPDs but payments for ASC patients were higher than payments for HOPD patients.


Our findings support the argument that outpatient total joint replacement is appropriate for select patients treated in both HOPDs and ASCs, although in the commercially insured population, the latter services may come at a cost. Until further study of outpatient total joint replacement in the Medicare population becomes available, how this will extrapolate to the Medicare population is unknown.

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