Costs of Outpatient TKA Higher Than Unicompartmental Knee Arthroplasty

A presentation at the 30th AAHKS Annual Meeting reported on a study comparing the true facility costs of patients undergoing outpatient total knee arthroplasty (TKA) with those undergoing unicompartmental knee arthroplasty (UKA). The study is in response to the removal of TKA from the Centers for Medicare and Medicaid Services (CMS) Inpatient Only list.
 
Researchers reviewed 2,310 outpatient TKA and 231 UKA patients from 2015-2019 performed by 31 surgeons at two hospitals. If the patient’s hospital stay was less than two nights they qualified as outpatient. Facility costs were determined by comparing implant costs, supplies, medications and personnel costs between TKA and UKA patients using a time-driven activity-based costing algorithm.
 
Lead author, Emanuele Chisari, M.D., and co-authors Michael Yayac, M.D., Chad A. Krueger, M.D., Jess H. Lonner, M.D., and P. Maxwell Courtney, M.D., found that when compared to patients undergoing UKA, outpatient TKA patients had higher mean implant costs ($3,403 vs. $3,081, p<0.001) and overall hospital costs ($6,350 vs. $5,594, p<0.001). The review also found that outpatient TKA patients had a greater length of stay (1.2 days vs. 0.5 days, p<0.001) and great postoperative personnel costs ($783 vs $166, p<0.001) than UKA patients. It was noted that TKA patients did have higher body mass indexes and older ages when compared to UKA patients (p<0.005).
 
The study concluded that “despite the TKA now being reimbursed from CMS at the same rate as UKA, TKA has increased facility costs to the hospital and CMS should consider appropriately reimbursing outpatient TKA for the additional personnel costs due to a longer length of hospital stay when compared to UKA.”
 
The study abstract can be found here.