AAOS Now

Published 9/2/2021
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Ariel DeMaio

Outpatient TJAs Performed at ASCs Are Associated with Lower Costs, Admission Rates Than Those Performed at HOPDs

The type of facility where an outpatient total joint arthroplasty (TJA) is performed significantly impacts outcomes, complications, and costs associated with the procedure, according to an analysis that appeared to favor performing TJAs at ambulatory surgical centers (ASCs) over hospital outpatient departments (HOPDs).

The findings will be presented by Azeem Tariq Malik, MD, an orthopaedic surgery resident from The Ohio State University Wexner Medical Center, as a poster on display during the Thursday–Friday poster session.

“Although TJAs are historically considered as inpatient surgeries, the rising costs of healthcare, coupled with advancements in technology and perioperative care, have urged physicians to consider transitioning this procedure to the outpatient setting,” the authors explained. For this analysis, Dr. Malik and researchers assessed the safety and value of undergoing TJA at either type of outpatient facility.

They queried a private payer claims dataset of Medicare Advantage, Medicaid Managed Care, and commercially insured patients for elective total hip arthroplasty (THA) or total knee arthroplasty (TKA) claims between 2007 and 2017. Researchers identified patients who underwent procedures at HOPDs (location code ‘22’) or freestanding ASCs (location code ‘24’).

The cohort was stratified according to surgery type (TKA or THA) and by surgery setting (ASC or HOPD). Next, a propensity-scoring model, which accounted for differences in age, gender, race, region, comorbidity burden, and plan type, was used to create “matched” groups of patients undergoing surgery at ASCs and HOPDs.

Investigators performed multivariable logistic regression and generalized linear modeling to assess for any significant differences in 90-day outcomes and costs between ASCs and HOPD.

The cohort included:

  • TKAs: 320 in ASCs and 3,901 in HOPDs
  • THAs: 230 in ASCs and 1,700 in HOPDs

Propensity-score matching identified a matched group of 588 TKAs (ASC, 294; HOPD, 294) and 426 THAs (ASC, 213; HOPD, 213).

In the TKA cohort, the authors found no significant differences in 90-day outcomes between ASCs and HOPDs, with similar rates of medical complications, wound complications, bleeding, implant-related complications, revisions, and emergency department visits. However, readmission rates were significantly lower for TKAs performed in an ASC compared to an HOPD (6.1 percent versus 10.9 percent; P = 0.029).

For THAs, the researchers observed significantly lower rates of 90-day revisions (0.5 percent versus 5.2 percent; P = 0.016) and readmissions (6.6 percent versus 12.7 percent; P = 0.025) when procedures were performed at an ASC as opposed to an HOPD. Again, they noted no differences in rates of medical complications, wound complications, bleeding, implant-related complications, and ED visits between either outpatient facility cohort.

Notably, performing surgery in an ASC versus an HOPD resulted in significant risk-adjusted cost savings, from $5,400 per case for TKAs to $7,800 per case for THAs.

“Based on the results, it appears that performing elective TJAs at a freestanding ASC, versus an HOPD, is associated with largely similar complication rates, slightly lower readmission rates, and approximately $5,000 to $8,000 cost savings per case,” the authors concluded.

The study will be on display as P0740 today and tomorrow in Academy Hall, Sails Pavilion, from 7 a.m. to 5 p.m.

Dr. Malik’s coauthors of “Total Joint Arthroplasty in Free-standing Ambulatory Surgical Centers vs. Hospital-Owned Outpatient Departments–An Analysis of 90-day Complications and Costs” are Adam Mark Gordon, MD; Daniel Li, MD; Mengnai Li, MD; Ryan Todd Voskuil, MD; Safdar Nasim Khan, MD; and Thomas J. Scharschmidt, MD.

Ariel DeMaio is the managing editor of AAOS Now. She can be reached at ademaio@aaos.org.