26 year old male with sickle cell disease and early AVN before collapse treated with core decompression and insertion of tantalum trabecular metal rod.

Avascular necrosis (also known as AVN or osteonecrosis) of the femoral head is a condition where there is disruption of the blood supply to the ball of the hip joint. The cause is unknown in a number of cases but it can be associated with alcohol excess and steroid treatment for conditions such as kidney disease, juvenile rheumatoid arthritis and systemic lupus erythmatosus (SLE).

It is common in patients with sickle cell disease. This causes death of the bone, which is can be very painful. The dead bone is not as strong as living bone and with time the dead bone collapses so that the ball is flattened and no longer spherical. This leads to shortening, reduced range of hip movement and secondary arthritis of the hip.

Once collapse has occurred the most effective treatment is a total hip replacement; collapse is easily seen on normal xrays. However if the disease is identified before collapse (normal xrays) on an MRI scan it can be treated by drilling the femoral head, a procedure called core decompression. This procedure decompresses the bone and stimulates healing provided the area of dead bone is not too great. A metallic rod can be inserted in addition to reduce the risk of subsequent collapse.