Worse Patient-Reported Outcomes and Spino-pelvic Parameters after Total Hip Arthroplasty for Rapidly Progressive Osteoarthritis of the Hip Compared to Osteoarthritis: A Propensity-matched Cohort Study

Background This study aimed to assess the association between the disease process of hip osteoarthritis and total hip arthroplasty (THA) outcomes; this is a critical issue, as rapid progression has been postulated to be responsible for patient dissatisfaction post-THA. Methods This retrospective case-control study included 255 patients who underwent THA and completed a mean follow-up duration of 42.1 months (range, 24.0 to 77.0). We classified patients into those who had (n = 26) and did not have (n = 229) rapidly progressive osteoarthritis of the hip (RPOA), defined as a narrowing rate of joint space ≥ 2 mm yearly or a ≥ 50% loss within 12 months, excluding any other cause of a destructive arthropathy. Propensity score-matched cohorts for age, sex, body mass index, and spino-pelvic measures were created, and the outcomes were compared between the two groups. Results After successfully matching RPOA (n = 25) and non-RPOA patients (n = 50), there were significant differences in minimum clinically important difference (P = 0.009 for European Quality of Life 5-Dimension [EQ-5D], and P < 0.001 for low back pain), patient acceptable symptom state (P = 0.015 for EQ-5D, and P < 0.001 for Hip Disability and Osteoarthritis Outcome Score Joint Replacement score), patient satisfaction (P = 0.028), and T1 pelvic angle (TPA) as an indicator of global sagittal spinal deformity (P = 0.017). There was a correlation between TPA and low back pain in the RPOA group (r = 0.628, P < 0.001). Conclusion Patients who exhibited RPOA before undergoing THA showed worse patient-reported outcomes compared to those who did not have rapid progression. Our study highlights the critical role of the disease process in influencing THA outcomes, advocating for a paradigm shift towards more meticulous preoperative evaluations, including global spinal deformity, standardized diagnostic criteria, and tailored interventions.