Osteonecrosis: When Bone Dies from Lost Blood Supply

What it is

Osteonecrosis is caused by reduced blood flow to the bones in joints. Healthy bone is constantly replaced by new bone; in osteonecrosis, lack of blood makes bone break down faster than the body can rebuild it. The bone begins to die and may collapse.

Where and who

• Where: one bone or several — most often the upper leg, and also the upper arm, knees, shoulders and ankles.
• Who: men and women of any age, but usually people in their thirties, forties or fifties.

Symptoms

• Early: often none.
• Later: joint pain that grows more severe, and trouble bending or moving the joint.

Risk factors

No one knows exactly what causes it, but risk factors include:

• long-term steroid treatment;
• alcohol misuse;
• joint injuries;
• certain diseases, including arthritis and cancer.

Diagnosis and treatment

• Diagnosis: imaging and other tests.
• Treatment: medicines; crutches and limiting weight-bearing activity on the joint; electrical stimulation; and surgery.

Sources

Based on "Osteonecrosis," MedlinePlus, U.S. National Library of Medicine, drawing on the NIH National Institute of Arthritis and Musculoskeletal and Skin Diseases; a work of the United States government in the public domain.