EP1.26 Magnitude of Acetabular Correction, Not Chronological Age, Predicts Functional Outcome After Periacetabular Osteotomy: A Prospective Cohort Study

Abstract Background Periacetabular osteotomy (PAO) is an established joint-preserving procedure for symptomatic acetabular dysplasia; however, the relative contribution of surgical correction compared with patient-related factors, particularly age, remains incompletely understood. Determining the true predictors of postoperative functional recovery is essential for optimizing patient selection and improving long-term outcomes. Purpose This study aimed to identify independent predictors of functional improvement following PAO, with specific evaluation of whether chronological age influences outcomes when controlling for correction magnitude and preoperative cartilage status. Methods A prospective cohort of 36 patients undergoing PAO for symptomatic acetabular dysplasia was analyzed at a minimum follow-up of seven years. All patients had Tönnis grade 0–2 osteoarthritis at baseline. Functional outcomes were assessed using the Harris Hip Score (HHS), while radiographic evaluation included measurement of the lateral center–edge angle (LCEA) and acetabular index (AI). Multivariate regression analysis was performed to determine predictors of functional improvement, defined as the change in HHS, incorporating age, cartilage status, body mass index, and magnitude of radiographic correction. A subgroup analysis compared outcomes between patients younger than 40 years and those aged 40 years or older. Results At a mean follow-up of 7.8 years, patients demonstrated significant and sustained functional improvement. Multivariate analysis identified the magnitude of LCEA correction as an independent predictor of functional gain (β = 0.41, p < 0.01). Chronological age was not a significant independent predictor after adjustment for cartilage status and correction magnitude (p = 0.21). Patients aged 40 years or older achieved improvements comparable to those of younger patients, although their absolute postoperative scores were slightly lower. All cases requiring conversion to total hip arthroplasty occurred in patients with preoperative Tönnis grade 2 osteoarthritis and suboptimal acetabular correction of less than 12 degrees. Conclusion Functional outcomes following PAO are primarily driven by the adequacy of acetabular correction rather than chronological age. Older patients with preserved cartilage can achieve meaningful improvement comparable to younger individuals, provided that optimal correction is achieved. Surgical planning should prioritize precise restoration of acetabular coverage, and age alone should not be considered a contraindication for PAO in appropriately selected patients.