Patient-Level Value Analysis in Primary Total Knee Arthroplasty: An Analysis of Time-Driven Activity-Based Costs and...

Value in health care is defined as optimized patient-centered outcomes and streamlined costs of care. A patient-level value analysis (PLVA) is a novel value-based health care research method. In a PLVA, the ratio of outcomes to cost is calculated for each individual patient in a cohort, and factors that optimize value are investigated. We performed a PLVA in primary total knee arthroplasty (TKA). We conducted a retrospective analysis of a prospectively maintained multi-institutional arthroplasty registry. A total of 2,789 primary manual TKAs were analyzed. Knee Osteoarthritis Outcome Score-Physical Function Short-Form (KOOS-PS) scores and costs of care using time-driven activity-based costing (TDABC) were collected. All costs were converted from U.S. dollars to arbitrary cost units (CUs) to protect confidential hospital financial data. The primary outcome was the value quotient (Value _KOOS-PS), or the ratio of 1-year improvement in KOOS-PS to the cost of care, which was converted to a scale with a maximum of 100. Multivariable forward linear regression determined factors impacting value in primary TKA. The mean improvement in KOOS-PS was 15.2. The mean cost of care was 859 CUs. The largest contributors to cost were the implant cost (378 CUs, 44.0%) and intraoperative personnel cost (173 CUs, 20.1%). Patient and hospital factors independently correlated with improved TKA Value _KOOS-PS included home discharge (adjusted mean difference: +7.8; p < 0.001), outpatient surgery (adjusted mean difference: +3.6; p < 0.001), lower preoperative KOOS-PS score (adjusted mean difference: +0.6; p < 0.001), lower Charlson Comorbidity Index (adjusted mean difference: +0.6; p = 0.006), and lower body mass index (BMI; adjusted mean difference: +0.2; p = 0.001). Using TDABC and patient-reported outcome measures, we performed a PLVA. We found that the largest contributor to the cost of care was the implant cost. The highest value TKAs occurred in an outpatient setting with home discharges, for patients with more severe preoperative knee symptoms, fewer comorbidities, and lower BMI. Surgeons and hospital administrators can use these findings to inform strategies to optimize value in TKA.