Disease & Condition Information
Health Library

Avascular Necrosis (Osteonecrosis) of the Knee

Overview

This condition occurs when a bone's normal blood supply is disrupted. The affected bone cells die and the dead bone weakens. The bone may begin to fracture and collapse, leading to arthritis.

Spontaneous Osteonecrosis of the Knee

There are two distinct types of this condition. One type, called spontaneous osteonecrosis, almost always affects only one knee. Doctors aren't completely sure what causes it to develop, but it seems to be linked to injury of the knee joint. Spontaneous osteonecrosis of the knee is most common in women who are older than age 55.

Secondary Osteonecrosis of the Knee

The other type is called secondary osteonecrosis. It usually affects both knees. Its cause is unknown, but it is linked to a variety of risk factors. These include corticosteroid use, alcohol abuse, and blood clotting disorders. Secondary osteonecrosis of the knee is most common in women who are younger than age 55.

Symptoms

Symptoms vary depending on the type of osteonecrosis. Spontaneous osteonecrosis typically causes the sudden onset of pain. This pain may be most noticeable during episodes of increased activity. It may occur when bearing weight or when climbing stairs. Pain may also occur at night. Secondary osteonecrosis is often associated with chronic, deep-rooted pain. Both types of osteonecrosis can limit the mobility of the knee joint.

Treatment

Treatment options may include nonsurgical options such as medications, knee braces, crutches, and the limiting of activities that cause pain. In advanced cases, surgery may be needed to repair or replace the joint.

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.