Association Between Bone Trace Metal Accumulation and Idiopathic Aseptic Osteonecrosis of the Femoral Head in a Mining Region of Katanga (DR Congo)

Background : Aseptic osteonecrosis of the femoral head (ONFH) is a disabling orthopedic condition, frequently affecting young adults, with a multifactorial etiology. In mining regions such as Katanga (Democratic Republic of Congo), chronic exposure to trace metal elements (TMEs) raises concerns regarding environmental contributors to bone disease. This study aimed to evaluate the association between bone TME concentrations and the occurrence of ONFH in an environmentally exposed population. Methods : A case-control study was conducted between 2017 and 2025 at Medpark Clinic, Lubumbashi. Bone samples from 56 patients undergoing total hip arthroplasty were analyzed, including 36 cases of idiopathic ONFH and 20 controls with primary osteoarthritis. TME concentrations (Pb, Co, Cd, Cr, Zn, Cu, As, Mn, Mg, Ni, Al) were measured in femoral heads using Inductively Coupled Plasma–Optical Emission Spectrometry (ICP-OES). Exposure was defined by Z-scores >2 relative to a reference population. Bivariate and multivariate analyses were performed to assess associations. Results : Patients with ONFH were significantly younger than controls (mean age 49.5 vs. 62.9 years; p = 0.004). Bone concentrations of lead and cobalt were significantly higher in ONFH cases. Multivariate analysis revealed that elevated bone lead levels (adjusted OR = 20.4; 95% CI: 2.30–181.57) and age ≤50 years were independently associated with ONFH. No significant associations were found for other TMEs. Conclusion : This study provides the first direct evidence of a strong association between chronic bone accumulation of lead and cobalt and the development of aseptic osteonecrosis of the femoral head in a mining-exposed African population. These findings underscore the need for environmental surveillance and public health interventions in high-risk regions.