Javier Beltran

Chapter 103 – Osteonecrosis

Key Points Younger patients are affected more often by osteonecrosis than by osteoarthritis, and osteonecrosis has significantly greater long-term morbidity. Corticosteroids are the most common cause of nontraumatic osteonecrosis. The femoral head is the most common site of osteonecrosis. In rare instances, osteonecrosis of the jaw has been associated with bisphosphonate exposure. This phenomenon is more common with repeated intravenous infusions of bisphosphonates. Case reports of osteonecrosis of the jaw in association with other medications, such as denosumab, have been reported. 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, innate immunity, and oxidative stress may play a role in the pathogenesis of osteonecrosis. Epigenetics may alter the predisposition to develop osteonecrosis. MRI 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 surgical treatment of femoral head osteonecrosis has many variations, most symptomatic patients eventually require total hip arthroplasty. Knowledge of risk factors and early detection are crucial to the successful management of osteonecrosis. Because of the lack of successful treatment options, new modes of management focus on the prevention of osteonecrosis.