Osteonecrosis is a disease caused by reduced blood flow to bones in the joints.
In people with healthy bones, new bone is always replacing old bone. In osteonecrosis, the lack of blood causes the bone to break down faster than the body can make enough new bone. The bone starts to die and may break down.
You can have osteonecrosis in one or several bones. It is most common in the upper leg. Other common sites are your upper arm and your knees, shoulders and ankles. The disease can affect men and women of any age, but it usually strikes in your thirties, forties or fifties.
At first, you might not have any symptoms. As the disease gets worse, you will probably have joint pain that becomes more severe. You may not be able to bend or move the affected joint very well.
No one is sure what causes the disease.
Doctors use imaging tests and other tests to diagnose osteonecrosis. Treatments include medicines, using crutches, limiting activities that put weight on the affected joints, electrical stimulation and surgery.
Osteonecrosis can occur in people of any age, but it is most common in people in their thirties, forties, and fifties.
Osteonecrosis is caused when the blood flow to the bone decreases, but why this happens is not always clear.
Some known causes of osteonecrosis are:
- Steroid medications
- Alcohol use
- Increased pressure inside the bone.
Risk factors for osteonecrosis are:
- Radiation treatment
- Kidney and other organ transplants.
Osteonecrosis is more common in people with illnesses such as:
- Gaucher’s disease
- Caisson disease
- Blood disorders such as sickle cell disease.
Osteonecrosis can also affect people for no known reason, even if they have no other health problems.
When osteonecrosis first begins, you may not have any symptoms. You may start to feel pain when you put weight on a joint with osteonecrosis. As the disease gets worse, you may have more pain and the joint may hurt even when you rest. Pain may be mild or severe.
If the bone and joint start to break down, you may have severe pain and not be able to use the joint. For instance, if you have osteonecrosis in the hip, you may not be able to walk. The time from the start of symptoms to losing use of the joint can range from months to more than a year.
To diagnose osteonecrosis, your doctor will take your medical history and do a physical exam.
Your doctor may then order one or more tests to see which bones are affected:
- X ray
- Magnetic resonance imaging (MRI)
- Computed tomography (CT) scan
- Bone scan
- Bone biopsy
- Measure of the pressure inside the bone.
Treatment helps more if the disease is diagnosed early.
Treatment helps to keep bone in joints from breaking down. Without treatment, most people with the disease will have severe pain and limited movement within 2 years.
To decide on the best treatment, your doctor will find out:
- Your age
- The stage of the disease
- Where and how much bone has osteonecrosis
- The cause, if known. If the cause is steroid or alcohol use, treatment may not work unless you stop using those substances.
The goals in treating osteonecrosis are:
- To improve use of the joint
- To stop further damage
- To protect bones and joints.
For early stage disease, doctors may first order nonsurgical treatments. If they do not help, surgery may be needed.