Osteonecrosis

Osteonecrosis affects younger patients more often than osteoarthritis and has significantly greater long-term morbidity. Corticosteroids constitute the most common cause of nontraumatic osteonecrosis. The femoral head is the most common site of osteonecrosis. Bisphosphonate use is associated with osteonecrosis of the jaw. The final common pathway in the pathogenesis of osteonecrosis is disruption of blood supply to a segment of bone. Abnormalities in lipid metabolism, bone homeostasis, regulation of apoptosis, coagulopathies, and oxidative stress may play a role in the pathogenesis of osteonecrosis. Magnetic resonance imaging is currently the optimal test for early diagnosis and identification of the extent of osteonecrosis. Nonsurgical treatment of osteonecrosis does not change the natural history of the disease. Although there are many variations on surgical treatment of femoral head osteonecrosis, most patients eventually require total hip arthroplasty. Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis. Due to the lack of successful treatment options, new modes focus on prevention of osteonecrosis.