Factors influencing the survival status of the hip joint in post-collapse femoral head necrosis

Abstract

Background Despite hip function typically deteriorating in the post-collapse stage of osteonecrosis of the femoral head (ONFH), some patients can still demonstrate long-term favorable hip function, a state termed "survival with collapse". This study aims to identify the characteristics of patients suitable for "survival with collapse" in cases of ONFH.Methods This cross-sectional study included 65 patients (87 hips) diagnosed with post-collapse ONFH for ≥ 3 years (average 9.1 years, range 3-23 years). Hip function was assessed using the Harris Hip Score (HHS). Demographic, clinical, and radiographic data were compared between the favorable group (HHS > 80) and the poor group (HHS ≤ 80). Independent protective factors for hip function were identified by multivariate analysis and receiver operating characteristic (ROC) curve analysis was further applied to evaluate these factors' diagnostic efficacy. ResultsThe favorable and poor groups included 46 and 41 hips, respectively. Significant differences were found in body mass index (BMI), Association Research Circulation Osseous (ARCO) stage, collapse degree, Japanese Investigation Committee (JIC) classification, necrotic size, and hip subluxation between the two groups (p < 0.05).