Osteonecrosis (ON) is a disease that affects the bone and leads to the breakdown of the
bone. Literally, the term means death of bone (osteo = bone, necrosis = death).
The disease affects the hip, knee and ankle joints. However, osteonecrosis of the hip
accounts for more than 90 percent of all osteonecrosis cases.
Approximately 10,000 to 20,000 people develop osteonecrosis in the U.S. This disease
primarily develops in people between the ages of 20 and 40. The average age is 38. If you
are healthy, your chances of developing osteonecrosis are quite small.
Children and teenagers can develop a form of osteonecrosis called
Legg-Calve-Perth's disease. The top or head of the femur (thighbone) loses
circulation and the bone cells die. The bone becomes soft and liable to collapse under
pressure. After a period of time, the head of the femur will heal in the collapsed
position leading to stiffness and pain.
Causes of Osteonecrosis Symptoms
There are two primary forms of osteonecrosis: post-traumatic and non-traumatic. A minor
injury will not cause ON and even most major traumas do not result in the disease.
Fractures where the blood vessels to a section of the bone are damaged have a chance of
resulting in ON.
Non-traumatic osteonecrosis is associated with other diseases such as lupus, kidney and
liver disease, sickle-cell disease, gout and clotting disorders. Drinking large amounts of
alcohol and receiving high-dosage shots of cortisone can also increase your chances of
developing the disease. However, over 30 percent of all people who develop osteonecrosis
are otherwise healthy. Doctors do not know why those people develop the condition.
Despite what caused the disease to develop, whether it was due to an injury or an
existing condition, the symptoms and course of the disease are similar.
The first symptoms commonly are pain and aching in the affected joint when it is being
used. The symptoms will start out slowly but will increase over time. Stiffness and
limping becomes common. The pain will be most likely concentrated in the groin area in hip
Unfortunately, by the time most people feel the first symptoms the disease has already
progressed. Your doctor will be able to use x-ray to diagnose the disease. The x-ray will
be able to show the area of the bone that is involved. In the earliest stages of the
disease, however, x- ray will not detect ON. In addition to x-ray, your physician may use
a tool called Magnetic Resonance Imaging (MRI) to detect ON. MRIs are able to find tissue
changes. A CAT scan, which is series of x-rays projected in a three dimensional figure,
may also be used to diagnose ON.
Treatments of Osteonecrosis and Osteonecrosis Symptoms
If the disease has progressed without detection for a long period of time, it will be
harder to treat and save the joint. Since osteonecrosis of the hip is by the far the most
prevalent, the following surgical treatments pertain to hip joints.
Non-surgical treatment options include the use of walkers and crutches. These devices
can help manage the pain while at the same time protect the joint until surgery. In
addition, the use of walkers and crutches can stop the progression of the disease while
other associated medical conditions are treated. However, this is not a long-term solution
and surgery is usually recommended. Today, joint replacements are largely successful but
when at all possible, your physician will try to save the original hip.
There are several surgical treatment options for osteonecrosis, including:
- Core decompression -- This simple procedure is used in mild to moderate cases. A hole is
created in the bone and a part of the bone is removed from the hip area. The use of
crutches is necessary for 6 weeks after the procedure to avoid fracturing the bone.
- Bone grafting -- The dead bone is removed and a bone graft is put in its place. The bone
graft is taken from the patient or from a bone bank. Crutches and/or walkers will need to
be used for up to a year to help the healing process.
- Vascularized bone grafting -- Similar to above procedure, the dead bone is removed and a
bone graft is put in its place. The difference is that in vascularized bone grafting the
bone graft comes with its own blood vessels. The body then doesnt have to create a
fresh blood supply.
- Osteotomy -- This procedure is not commonly performed, but may be used in special cases.
The bone is cut below the infected area and turned so that another portion of the bone
that is not affected by ON is the new weight- bearing area.
- Femoral head resurfacing -- A metal head is placed over the original femoral head to
slow the progression of the disease. Over time, a complete femoral head replacement will
need to be performed.
- Femoral head replacement -- The femoral head is replaced and a stem is placed inside the
- Total hip replacement -- Once the disease has progressed to the point the hip socket is
affected, a total hip replacement may be necessary. Hip replacements are usually
successful. The downside is that with todays technology, a total hip replacement may
not last as long as the life of the patient. That is why surgeons will wait to perform the
operation until it is absolutely necessary.