What is Osteonecrosis?

Orthopaedic & Spine Center

 

Jeffrey R. Carlson, MD

 

As a Fellowship-trained Orthopaedic Surgeon, I see people every day for a wide variety of bone and muscle problems.   Some conditions I treat regularly, such as knee arthritis or plantar fasciitis.  Other problems I diagnose more infrequently, like bone tumors or osteonecrosis.  However, just because I see less of them in my daily practice does not mean that I should not attempt to provide information about these less common conditions to patients (or potential patients) that may have questions.

Orthopaedic surgeon Dr Jeffrey Carlson

So if you come to visit me and I diagnose you with Osteonecrosis, what does that mean exactly?  First, I think it would be prudent to give a definition of the condition, to discuss what causes it and why it can happen to you.

Osteonecrosis literally means “death of the bone”.  Simply put, it is a loss of blood flow; therefore, loss of oxygen to the cells within the bone.  It is not a disease, but a lack of circulation. Usually, this happens in a small segment of a bone rather than an entire bone.  It can affect any of the large joints, but is most commonly seen in the shoulders and hips.

Circulation to the bone can be affected by many things:

1)    Use of oral steroids (most common reason)

2)    excessive use of alcohol (another common reason)

3)    trauma to the vessels feeding the bone, caused by injury

4)    blood clots or embolisms, like those caused by decompression sickness from scuba diving;

5)    radiation therapy

6)    fractures or dislocations near joints

7)    sickle-cell anemia

8)    Collagen disorders (Lupus, Sjogren’s disease)

People who have diabetes, gout or build-up of plaque in their arteries are at increased risk for this condition.  Although it can affect both sexes, it most commonly affects men, and tends to happen in the 30s, 40s, and 50s, although it can strike at any age.  Sometimes, osteonecrosis does not have an apparent cause.  This is called idiopathic osteonecrosis.

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Osteonecrosis progresses in pretty much the same fashion, no matter the causative factor involved.  Because bone is continually nourished by the blood, it quickly dies when deprived of its food and oxygen supply.  When this happens, your body will attempt to repair any damage to the bone through a very complex process called bone remodeling.  If the dead area of bone is very small, the body may be able to repair itself by adding new bone over the dead bone and restoring blood supply to the older bone.  This lesion may never be detected or bother the patient in any way.  This repair process can take up to two years, but for some patients, they will never even know that they had a problem with their bone.

For patients with more severe necrosis, this automatic bone remodeling process may not be able to adequately handle the size or severity of the problem.  Location also plays a big role here, as a hip being affected would be much more difficult than if a finger was affected.  In that case, surgical intervention may be required.

What are the symptoms of Osteonecrosis?  The main symptoms are a joint pain that increases over time, a limited range of motion in the joint and a joint which may hurt even when at rest.  Depending upon the location of the affected joint, a person may limp or try to accommodate their painful joint by altering their movements.  If the condition is advanced, the bone can collapse, which results in severe pain.  The bone is the support structure for the cartilage in a joint, so if the bone collapses, the cartilage in the joint may also be destroyed by this process as well.   Walking on a joint without cartilage to cushion the bone can cause great pain and disability when the joint bears weight.  Movement of the joint can also be very painful, as the cartilage surface will not be smooth and will cause grinding.

When a patient comes to me experiencing pain in the bone or joint, I perform a physical examination with specific activity tests that I ask them to perform.  In this way, I can best determine if the patient is being affected by arthritis, a musculoskeletal problem or something that needs further investigation.  I will ask the patient specific questions about the pain they are experiencing, when it happens, does the intensity of the pain vary, does it get better with rest, etc.  During this examination, I piece together the symptoms and confirm my suspicions by doing specific imaging tests.

Osteonecrosis can be definitively diagnosed by using X-Ray, Bone Scan, CT Scan or MRI imaging studies.  The best imaging study that I order when I suspect osteonecrosis is an MRI.  The MRI will show the reparative response of the bone in contrast to the bone without blood flow and can give a stark contrast which is very recognizable.  If for some reason the diagnosis is questionable, a biopsy of the bone can also be performed for a pathological diagnosis.  A biopsy requires a needle to be placed in the bone to remove a piece that can be analyzed under a microscope.  This test requires an invasive procedure and can be painful but is very rarely used as the MRI usually gives a definitive diagnosis.

When I have confirmed a diagnosis of osteonecrosis, I begin to look for the underlying reason.  For example, if the patient has a condition that causes their blood to clot, which results in a compromised blood flow to a specific area of bone, blood-thinning medications may help to dissolve the clots and get the blood flowing to the problem area of the bone again.  There may be other conditions where I can treat the underlying disease and affect a better outcome when I treat the osteonecrosis.

If I catch the condition in its early stages, I may have the patient rest the affected area and take over-the-counter pain relievers.  I may order physical therapy and in some cases, a brace or crutches.  This conservative treatment usually is a stopgap measure, but in a few cases, the problem will resolve.  I may also add the use of a bone-growth stimulator, which is an electronic device that supplies the bone with a gentle electric current to encourage healing and growth.

Usually a person with a confirmed diagnosis of osteonecrosis will require surgery to fix the problem.  Before I recommend a surgery to remedy the problem, I must take into consideration the following things:

  1. Location of the osteonecrosis
  2. Severity of the problem/stage of disease
  3. The amount of pain my patient has
  4. My patient’s age and physical condition

My options for surgery will usually involve cutting out the affected area of bone, or grafting bone, with or without its own blood supply, to the necrotized bone.  Sometimes I have to cut out the affected portion of the bone in a large chunk, taking out the diseased section, reattaching it to the other bone in the limb and stabilizing it with plates and screws so that it heals properly and relieves stress on the bone.  This is called osteotomy.  When the majority of a joint is affected, a total joint replacement may have to be performed.  A smaller procedure that is very commonly used is a “core decompression”. This procedure is performed by placing a drill into the affected bone to create a localized “fracture” scenario.  Whenever the bone is injured, the body responds by sending healing help in the form of blood vessels.  This new controlled “fracture” stimulates the body to grow new blood vessels in the area of necrosis, which should form new bone and allow for healing.

All of these surgeries are complex and the outcomes from the surgery can vary from permanent disability to complete healing and restoration of function.  That is why it is important to choose a highly-skilled surgeon with an Orthopaedic Fellowship who has experience in performing these types of surgeries.

My patients who do the best after surgery for osteonecrosis usually are younger and more motivated to return to their full activities.  A typical recovery period can range from 6 weeks for a joint replacement, to 3 months for a bone graft surgery.  Although the joint replacement may have a shorter recovery time, in younger patients, we will try to maintain the patient’s own bone rather than replacing it.  In bone preservation surgery, it is imperative to restrict activities and allow the blood vessels to form and provide the nutrition that is needed to heal the bone.

Most cases of osteonecrosis cannot be prevented; however there are things that you can avoid to lessen your risk.  They are:

  1. Avoid excessive alcohol consumption
  2. Avoid excessive steroid use
  3. Avoid getting decompression sickness when scuba diving

Getting a diagnosis of osteonecrosis can be scary; however, treating it effectively can best be accomplished through a partnership with a qualified, Fellowship-trained Orthopaedist who can evaluate and diagnose your condition and make the best recommendations based on your personal circumstances.

Dr. Jeffrey R. Carlson is a Fellowship-trained, Board-certified, Orthopaedic Spine Specialist who practices at Orthopaedic & Spine Center in Newport News, VA.  Dr. Carlson currently serves as Chief-of- Surgery at Mary Immaculate Hospital in Newport News, VA.  For more information about Dr. Carlson and his practice, go to www.osc-ortho.com .  Check out the Patient Testimonials posted by Dr. Carlson’s patients.  For an appointment, call 757-596-1900.