An Analysis of Costs in the Year Before and After Total Knee Arthroplasty.

Background: While insurance claims database studies have reported on costs before total knee arthroplasty (TKA), the cost-efficacy of nonoperative treatment remains unclear in patients who eventually undergo TKA. Furthermore, we hypothesized that patients undergoing primary TKA would have lower costs in the year following surgery than if patients continued nonoperative treatment. The purpose of this study was to determine the costs of various nonoperative treatment modalities in the year before and following primary TKA.

Methods: We reviewed a consecutive series of 13,117 patients undergoing primary TKA from 2020 to 2022 at a single institution with claims data from Medicare and a single commercial payer. We recorded all office visits, intra-articular injections, bracing, physical therapy, and imaging in the 12 months before and immediately following the patient's primary TKA, analyzing costs by the payer. Patient-reported outcome scores, readmissions, and reoperations were also noted, and costs were included in the 12-month postoperative analysis.

Results: There were 5,516 (42.1%) patients who were insured by Medicare, 5,044 (38.5%) commercially insured and 2,557 (19.4%) insured by Medicare Advantage The mean total cost in the year before and after TKA declined from $760 to $598 (commercial), $583 to $351 (Medicare Advantage), and $580 to $370 (Medicare). Medicare patients had the greatest number of nonoperative treatments (6.5 versus 5.3 versus 5.1, P < 0.001) in the year before TKA. Patients in all three groups achieved the minimum clinically important difference for the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement at similar rates (74.8 versus 75.6 versus 72.7%, P = 0.35).

Conclusions: Patients undergoing primary TKA had lower costs in the year following surgery than they did with trial nonoperative treatment in the year prior. Further studies are needed to evaluate the cost-efficacy of nonoperative treatment modalities.