CMS-Proposed Substantial Clinical Benefit Thresholds Correlate with Patient-Reported Measures After Primary Total...

The U.S. Centers for Medicare & Medicaid Services (CMS) requires the collection of patient-reported outcome measures (PROMs) after primary total joint arthroplasty (TJA), with penalties for noncompliance affecting all Medicare reimbursement. The CMS will publish risk-standardized improvement rates based on substantial clinical benefit (SCB) thresholds of 22 points for the HOOS JR (Hip disability and Osteoarthritis Outcome Score for Joint Replacement) and 20 points for the KOOS JR (Knee injury and Osteoarthritis Outcome Score for Joint Replacement). Our aims were to determine if preoperative scores predicted postoperative PROMs, to externally validate the SCB thresholds, and to analyze them with different anchors.

We retrospectively identified patients who underwent TJA at our institution between 2015 and 2023. The HOOS JR and KOOS JR were prospectively collected in the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI); all other variables were obtained from electronic medical records. Logistic regression analyses and anchor-based receiver operating characteristic curves were generated to determine threshold values and the efficacy of using preoperative and postoperative scores as predictors of patient improvement, satisfaction, and willingness to repeat surgery.

In total, 3,465 cases (1,498 total knee arthroplasties [TKAs] and 1,967 total hip arthroplasties [THAs]) were included. Preoperative scores failed as predictors (area under the curve [AUC], <0.6) of patient improvement, satisfaction, and willingness to repeat surgery. The change in scores for TKA, particularly at 1 year postoperatively, was predictive of improvement (AUC, 0.79), satisfaction (AUC, 0.77), and willingness to repeat surgery (AUC, 0.71); and the change in scores for THAs was predictive of improvement (AUC, 0.85), satisfaction (AUC, 0.82), and willingness to repeat surgery (AUC, 0.77). The Youden index indicated that change thresholds of 24 points for patient improvement, 24 points for satisfaction, and 26 points for willingness to repeat surgery provided the best predictions at 1 year after THA. Similarly, change thresholds of 21 points for patient improvement, 22 points for satisfaction, and 24 points for willingness to repeat surgery provided the best predictions at 1 year after TKA. Twenty percent of patients did not achieve CMS-proposed SCB thresholds.

Although preoperative scores were not predictive of patient-reported outcomes, the degree of score improvement postoperatively was strongly associated with patient improvement, satisfaction, and willingness to repeat surgery. CMS-proposed SCB thresholds appear to be validated in our population and compare favorably with the thresholds produced in this study.

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.