The Frank Stinchfield Award: How Accurate Is the United States Centers for Medicare & Medicaid Services Definition of Success for Patients Undergoing Total Hip Arthroplasty?

Abstract

Total hip arthroplasty (THA) is a highly effective treatment for patients who have advanced arthritis. The United States Centers for Medicare & Medicaid Services (CMS) defines a successful THA as achieving a minimum 22-point improvement in the Hip Injury and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR). However, the accuracy of this criterion and how it correlates with patient satisfaction remains unclear. This study aimed to evaluate the validity of the CMS success criteria following primary THA. A multicenter cohort of 6,016 patients undergoing primary THA was prospectively enrolled. Patient demographics, comorbidities, and HOOS-JR scores were collected preoperatively and at one year postoperatively. Patient satisfaction was assessed using the International Society of Arthroplasty Registries scale. Patients were categorized as successful or unsuccessful based on CMS criteria and as satisfied or not satisfied based on the International Society of Arthroplasty Registries scale. Cross-classification of outcomes was performed, and a multivariate logistic regression model was used to identify factors associated with patients satisfied after THA yet labeled as "unsuccessful" by the CMS. A total of 5,429 patients (90.2%) reported satisfaction; however, only 4,625 patients (76.9%) met the CMS criteria for success. Among satisfied patients, only 4,397 patients (81%) were classified as successful by CMS standards. Discordance between success and satisfaction was strongly associated with baseline HOOS-JR. Predictors of satisfied patients classified as having unsuccessful outcomes include high body mass index, prolonged narcotic use, back pain, contralateral hip pain, health literacy, and poor baseline HOOS-JR and Veterans Rand 12-Item Health Survey mental component summary. Satisfied patients who had higher baseline HOOS-JR scores by 10 points were 2.7 times more likely to be classified as having an "unsuccessful outcome" by CMS. A substantial discrepancy exists between patient satisfaction and the CMS definition of success following THA. A more nuanced, risk-adjusted success metric that accounts for preoperative baseline scores may better align with patient-centered outcomes and improve its accuracy in defining successful outcomes after THA.