[Hip osteonecrosis].

Hip osteonecrosis. Hip osteonecrosis of the is a relatively common pathology, responsible for pain and functional disability mainly affecting young people. It corresponds to bone necrosis of the femoral head, secondary to ischemic and/or cytotoxic mechanisms. They can be unilateral, bilateral or multifocal, thus testifying to the systemic nature of their origin and the importance of the general factors involved in their occurrence. Many risk factors are to be looked for, such as corticosteroid therapy, alcohol abuse, dyslipidemia or sickle cell anemia. MRI is the examination that allows a positive diagnosis and should be offered in the face of any unexplained pain in the young subject, with a normal X-ray. In advanced forms with a collapse of the joint surface and then secondary arthritis, surgical treatment with arthroplasty is the main possible option. The hip prosthesis provides these patients with a comfortable life; but it is not without risk taking into account the pathology which is usually the cause of osteonecrosis: in fact, osteonecrosis of the hip is often associated with serious medical pathologies such as hemoglobinopathies (sickle cell anemia in particular), taking corticosteroids in large doses in connection with organ transplantation or diseases such as lupus erythematosus, autoimmune diseases, hyperlipidemias and excessive alcohol intake. However, there are promising therapeutic advances, such as the use of mesenchymal stem cells, which could in the future improve the poor joint prognosis of aseptic osteonecrosis. These conservative treatments are recommended at a stage without collapse of the articular surface.