Osteonecrosis, also called avascular necrosis is death of the bone tissue and marrow. In marrow infarctions, the cancellous bone and marrow are involved while the cortical bone is usually not damaged and neither is the underlying cartilage.

There are various causes. Post trauma, long term cortisone therapy, autoimmune diseases, chemotherapy, air or fat embolism are some of the primary ones but in most causes the cause remains unknown.

Osteonecrosis can, in theory, affect any epiphyseal segment of the bone but the one usually affected is the femur at both the head (hip) and condyle (knee). Even the talus (foot/ankle bone) and the humeral head can sometimes be affected by this disease. The systems are often delayed and difficult to interpret, mostly involving pain in the limb.

Diagnosis is usually made through an MRI or CT as traditional x-rays are often negative in the first 6 months after the disease starts. If not treated, osteonecrosis evolves into structural collapse of the trabecular bone and deformation of the bone profile with subsequent joint incongruity that can lead to serious secondary arthritis. They possible treatments depend upon the degree and extension of the necrotic area.

In cases of low-grade damage and those of minimum size, conservative treatments can be tried such as weight bearing restriction and hyperbaric oxygen therapy and/or shock wave therapy. In cases with a greater degree of damage or those that are larger in size, surgery is required to remove the diseased tissue and possibly a graft of growth factors (bone protein) and/or mesenchymal stromal cells and/or support scaffolds. We have now treated over 100 cases of avascular necrosis of the femoral head using this method with excellent results, saving the femoral head and avoiding prosthesis in 85/90% of cases.

In cases where there is impaired cortical profile and/or arthrosic cartilage alterations, prosthetic replacement of the segment involved is often necessary. Considering that osteonecrosis of the femoral head affects mostly young and active patients, it is easy to imagine the high social cost of this pathology with severe patient morbidity and disability.