[Proximal humerus fractures: clinical assessment and functional outcome in patients with osteonecrosis of the humeral head].

Introduction: Fractures of the proximal humerus resulting in three or more fragments represent a high risk of necrosis. The former is the second most frequent site of necrosis, only after the femur, due to either traumatic or nontraumatic causes. The former are the most common, with an incidence rate of necrosis of 13-34% in fractures with more than four fragments.

[Nontraumatic causes of bilateral avascular necrosis of the femoral head: link between hepatitis C and pegylated interferon].

Background: Avascular necrosis of the femoral head is a frequent condition in patients with a history of trauma. The major pathologic causes include vascular diseases, malignancies, hypercoagulability states, long-term steroid treatment, and some patients have a history of hepatitis C infection treated with pegylated interferon and ribavirin. Upon studying the behavior of the hepatitis C virus, Seef, Foster and Poynard found a hypercoagulability state that causes interruption of retinacular blood flow to the femoral head, without an increased incidence of osteonecrosis in this patient group.