Pub. date: 2008 | Online Pub. Date: September 15, 2008 | DOI: 10.4135/9781412963954 | Print ISBN: 9781412959087 | Online ISBN: 9781412963954| Publisher:SAGE Publications, Inc.About this encyclopedia
Clinical Trials outside U.S.: Avascular Necrosis
Anjan P. Kaushik
AVASCULAR NECROSIS (AVN), or osteonecrosis, is a painful condition in which bone tissue dies as a result of ischémie injury and is unable to regenerate itself. The head of the femur is affected in 90 percent of patients and is caused most commonly by traumatic hip injury but can also result from alcoholism, excess steroid use, vasculitides or coagulop—athies, Caisson disease, iatrogenic injury during hip surgery, radiation exposure, and sickle cell disease. In children, AVN of the femoral head can result from Legg—Calvé-Perthes disease, slipped capital femoral epiphysis (SCFE), and congenital hip dys—plasia. Other sites of avascular necrosis include the humérus of the upper arm, femoral condyles of the knee, scaphoid and lunate bones of the wrist, calca—neus and navicular bones of the foot, and the jaw. AVN mostly occurs in adults age 25 to 50 and in younger children, and it is more common in males than females (ratio ...