In this study, the aim is to identify the modifications responsible for aseptic osteonecrosis of the femoral head and its structural evolution by the association of the micro scanner analysis and Raman spectrometry performed on the femoral heads removed during hip replacements. The study of femoral heads will allow the analysis of bone tissue at two different scales, both correlated with the biomechanical properties of the bone. Also, the association with preliminary MRI analysis will provide pathogenic explanations correlated to these modifications.

Inclusion Criteria for experimental group:

• Men
• Patients aged from 25 to 70 years
• Patient with an aseptic osteonecrosis of the femoral head established by medical Imaging (CT-scan, MRI or radiography)
• FICAT stage 3 or 4
• osteonecrosis etiologies : alcohol, corticosteroid therapy, idiopathic
• Surgical indication of hip prosthesis determined

Inclusion Criteria for control group:

• Men
• Patients aged from 40 to 70 years
• Patient with a primitive coxarthrosis
• Surgical indication of hip prosthesis determined

Exclusion Criteria for the 2 groups:

• Other causes of osteonecrosis (coagulopathy, barotrauma, trauma)
• Prior fracture of the upper extremity of the femur
• Prior cancer and hematological malignancies with bone locations
• Prior debilitating bone diseases
• Patient refusal to participate in the study
• Patient who isn't affiliated to a social security regimen