Avascular necrosis (AVN), or osteonecrosis or bone infarction, is death of bone tissue attributed to interruption of the blood supply. At the onset, there may be no symptoms. But gradually joint pain may develop and may limit the ability to move. Complications include collapse of the bone or joint surface.
In sickle cell disorder, the risk factor of having AVN is very high due to the complications from restricted blood supply to vital organs in the body. Up to 50% of sickle cell patients may develop AVN by the time they reach the age of 35. However, it is very rare in sickle cell trait (SCT), a much milder form of sickle cell disease in which patients are usually asymptomatic.
Treatment for AVN is recommended based on the stage of the disease coupled with the age of the patient. In Stage I, medication and crutches may be prescribed to provide relief and enable the bone to heal on its own. This treatment may require the patient to be non-weight-bearing for up to six months. It also has a failure rate greater than 80-percent.