Predicting Medicare Candidates for Outpatient Hip Arthroplasty

Much as it did with total knee arthroplasty, the Centers for Medicaid and Medicare Services (CMS) is gearing up to promote outpatient total hip arthroplasty.

BUT not all Medicare patients should have large joint arthroplasty in the outpatient setting. How to predict which are best suited for outpatient, particularly among the Medicare population?

That was the question that a group of University of Connecticut researchers decided to tackle with this novel and important research.

Their study, “Predicting Inpatient Status After Total Hip Arthroplasty in Medicare-Aged Patients,” appears in the February 2019 edition of The Journal of Arthroplasty.

Mohamad Halawi, M.D. an orthopedic surgeon at the University of Connecticut Health Center in Farmington and co-author on the study, explained the objective of this study to OTW. “Effective January 1, 2018, the Centers for Medicare and Medicaid Services (CMS) removed total knee arthroplasty (TKA) from its inpatient-only list. This move has created significant confusion among surgeons and hospitals due to limited information on the selection criteria for outpatient vs. inpatient surgery in this patient population.”

“As a result, arthroplasty surgeons have come under increased pressure by regulatory entities to default to outpatient status for most TKAs despite lack of evidence to support this practice.”

“Currently, CMS is soliciting public comments to follow the same suit for total hip arthroplasty (THA). In anticipation for such a policy change in the near future, we aimed to ignite interest and discussion early in the process, so we are better prepared and potentially avoid repeating the confusion that has afflicted the process for TKA.”

The authors used the American College of Surgeons National Surgical Quality Improvement Program database and analyzed 30,587 inpatient total hip arthroplasties and 17,024 outpatient THAs.

Dr. Halawi describe the study methodology to OTW, “Using a large national database, we identified a number of patient characteristics that are associated with a hospital length of stay (LOS) exceeding two midnights—this is the time benchmark established by CMS to qualify for inpatient status.”

“A simple, internally validated predictive nomogram was constructed based on those patient characteristics. It is important to note that 92% of patients analyzed in our study had LOS greater than two midnights. This indicates that while outpatient THA is feasible in Medicare-aged patients, it is certainly not the standard. This should be taken into consideration by policy and regulatory bodies.”

“We hope this work stimulates further interest and discussion in the arthroplasty community. Further studies are needed to externally validate our predictive risk stratification tool. Until we have well-established selection criteria, arthroplasty surgeons not experienced with outpatient surgery should not be pressured to default to outpatient admission in Medicare patients.”