bone, joint, and muscle disorders
Osteonecrosis
Causes of Osteonecrosis
Osteonecrosis is not a specific disease but a condition in which death of the bone is confined to one or more specific (localized) areas. There are two general categories of osteonecrosis: Traumatic (following an injury) Nontraumatic is the most common. The most frequent cause of traumatic osteonecrosis is a displaced fracture. In a displaced fracture, a bone breaks into two or more parts and moves so that the fractured ends are not lined up. The type of displaced fracture that causes osteonecrosis most often affects the hip (see Hip Fractures ) and most commonly occurs in older people. Another cause of traumatic osteonecrosis is a dislocation. A Overview of Dislocations occurs when the ends of bones in joints become completely separated from each other, as in a A displaced fracture or a dislocation may damage the blood vessels supplying the upper end of the thighbone (the femoral head, part of the hip joint), resulting in death of this part of the bone. This death of bone occurs less often in other areas of the body. Traumatic osteonecrosis Overview of Fractures (breaks in bones) and Nontraumatic osteonecrosis The most common factors causing or contributing to nontraumatic osteonecrosis are Use of corticosteroids (generally long-term and/or at high-doses) Excessive alcohol Other factors causing or contributing to nontraumatic osteonecrosis are Blood clotting (coagulation) disorders Chemotherapy Cushing Syndrome None Late effects of decompression sickness None Gaucher Disease None High level of lipids in the blood ( Dyslipidemia ) Human Immunodeficiency Virus (HIV) Infection None Liver disease Organ None Overview of Pancreatitis None Radiation Sickle Cell Disease None Smoking Systemic Lupus Erythematosus (SLE) and other Tumors Miscellaneous conditions (such as Chronic Kidney Disease and rare genetic mutations) Nontraumatic osteonecrosisoccurs without direct trauma or injury. This type may be caused by a disease or condition that results in the blockage of small blood vessels that supply certain areas of the bone. The areas most commonly affected are the femoral head (which is part of the hip joint), the knee, and the upper arm at the shoulder. This disorder affects men more often than women, occurs primarily in people between the ages of 30 and 50, and often affects both hips or both shoulders. The most common causes are Corticosteroid use (mainly when given at high doses, for long periods of time, or both) Chronic, excessive alcohol use (more than 3 drinks a day for several years) A number of other causes have been identified, but these occur much less often. These other causes include certain blood-clotting disorders, Sickle Cell Disease , liver disease, tumors, In approximately 20% of people with osteonecrosis, the cause is unknown. If one bone has nontraumatic osteonecrosis, the same bone on the opposite side of the body sometimes has it also, even if there are no symptoms. For example, if one hip is affected, approximately 60% of the time the other hip is affected. can occur in older people who have no specific risk factors for the disorder. SONK differs from other forms of osteonecrosis. SONK is thought to be caused by an insufficiency fracture. An insufficiency fracture occurs without direct trauma and is caused by normal wear and tear on bone that has been affected by Osteoporosis . However, osteonecrosis of the knee can also result from trauma or any of the 