Acetabular osteophyte-like ossification in DDH: association with labral morphology and age

Background Developmental dysplasia of the hip (DDH) is a common pediatric condition. The labrum-acetabular cartilage complex (LACC) undergoes morphological changes, but its relationship with acetabular osteophyte-like ossification (AOO) remains unclear. Purpose: To investigate the associations of AOO with LACC morphology and age.Purposes To investigate the associations of AOO with LACC morphology and age.Patients and Methods We retrospectively reviewed preoperative pelvic radiographs, MRI, and CT images of 180 patients (199 hips) with DDH from January 2015 to December 2022. Acetabular index (AI) and Tönnis grade were assessed on radiographs, LACC morphology classified on MRI, and AOO identified on multiplanar CT reconstructions. Group comparisons, multivariable logistic regression, interaction analysis, and ROC analysis were performed.Results AOO occurred in 44/146 (30.1%) inverted and 10/53 (18.9%) everted hips. In children >2 years, AOO was more frequent in the inverted group (p = 0.031), whereas no difference was found in those ≤2 years (p = 0.515). Multivariable analysis showed age was the most consistent independent correlate of AOO in the overall cohort (OR=1.022, p < 0.001). LACC morphology was not significant in the full model but became significant after excluding AI (OR=3.792, p = 0.012). In children >2 years, inverted LACC was independently associated with AOO (OR=7.66, p = 0.008), with a significant age-by-LACC interaction (p = 0.042). Age predicted AOO in both LACC groups (AUC 0.800 and 0.735). AOO predominantly involved the posterior acetabulum.Conclusion Age was the most consistent independent correlate of AOO, while the effect of LACC morphology was age-dependent. Inverted LACC was strongly associated with AOO in children >2 years with a posterior predilection. These exploratory and hypothesis-generating findings require prospective validation.