Measures of Clinical Meaningfulness for the Hip Disability and Osteoarthritis Outcome Score Vary by Aseptic Revision Total Hip Arthroplasty Diagnosis

Background: Patient-reported outcome measures (PROMs) are increasingly important in assessing revision total hip arthroplasty (THA) outcomes, yet diagnosis-specific thresholds for clinical relevance remain largely undefined. This study aimed to determine diagnosis-specific minimal clinically important difference (MCID), patient-acceptable symptom state (PASS), and substantial clinical benefit (SCB) thresholds for the Hip Disability and Osteoarthritis Outcome Score (HOOS) subscales in aseptic revision THA. Methods: A prospective cohort of 466 patients who underwent aseptic revision THA between 2016 and 2022 was analyzed. Patients were stratified by diagnosis: aseptic loosening (n = 232), implant failure (n = 112), instability (n = 78), and periprosthetic fracture (n = 44). The HOOS-pain, HOOS-physical function short form (PS), and HOOS-Joint Replacement (JR) scores were collected preoperatively and at a 1-year follow-up. The MCID was calculated using distribution-based methods, while PASS and SCB were determined using anchor-based approaches. Results: The MCID thresholds ranged from 10.0 (aseptic loosening) to 12.9 (periprosthetic fracture) for HOOS-pain, 9.9 (instability) to 12.9 (periprosthetic fracture) for HOOS-PS, and 8.7 (aseptic loosening) to 12.1 (periprosthetic fracture) for HOOS-JR. The PASS thresholds varied from 67.5 (implant failure) to 72.5 (periprosthetic fracture) for HOOS-pain, 76.6 (periprosthetic fracture) to 80.0 (aseptic loosening, implant failure, and instability) for HOOS-PS, and 64.7 (aseptic loosening) to 73.5 (implant failure and instability) for HOOS-JR. The SCB thresholds spanned 15 (implant failure) to 35 (aseptic loosening) for HOOS-pain, 4.6 (periprosthetic fracture) to 22.0 (instability) for HOOS-PS, and 16.1 (instability) to 25.9 (implant failure) for HOOS-JR. Conclusions: This study established diagnosis-specific thresholds for MCID, PASS, and SCB across HOOS subscales in aseptic revision THA, demonstrating significant variability by preoperative diagnosis. Patients who have aseptic loosening showed the greatest improvement and highest likelihood of achieving clinically meaningful benefits, while those who have periprosthetic fractures and instability had lower rates of meaningful recovery. These findings provide a critical framework for outcome assessment and personalized patient counseling.