Your hip pain might be the sign of a rare condition known as AVN

Cellular death in the hip area has nothing to do with your mobile phone, but it does have everything to do with mobility. An interruption of the blood supply to bone components, particularly the shoulders, knees and hips, is what causes cellular death.

Bone is alive, but without blood tissue it dies. And ultimately, this leads the bone to collapse. This disease is known medically as Avascular Necrosis or AVN, and has aliases the include osteonecrosis, bone infarction, aseptic necrosis or ischemic bone necrosis.

AVN is not life-threatening, but it is debilitating. Although it isn’t well-known and its cause is unknown, AVN affects 10,000 to 20,000 Americans annually. Risk factors for AVN include Caisson’s disease, glycogen storage disease, renal disease, Sickle cell anemia, alcoholism and steroid use. The disease also has been linked to anti-inflammatory usage.

Although the patient group is diverse, men in their 40s or 50s are at greatest risk of developing AVN. Between 40 and 80 percent of patients will experience AVN bi-laterally, which means that if they are diagnosed with the disease on one side, it also may occur on the opposite side.

Although a patient may not initially experience symptoms, hip pain usually is the first indicator.

The earlier the diagnosis is achieved, the better the patient’s potential outcome. AVN has four stages that can progress over a period of several months to more than a year.

In Stage I, the hip is healthy; in Stage II, the patient experiences mild pain in direct proportion to the deterioration of the head of the femur (or ball of the hip joint). By Stage III, the patient will find it difficult to stand and bear weight on the hip, and joint movement will be painful.

During this stage, the ball of the hip has deteriorated to what is called a subchondral fracture and early collapse. Stage IV is a full collapse of the femoral head and degenerative joint disease, or DJD.

After discussing a patient’s medical history and symptoms, a doctor will examine the hip to determine which motions cause pain for the patient. An X-ray will be evaluated to confirm the diagnosis. If damage isn’t indicated on the X-ray, a bone scan or MRI will aid in obtaining a more detailed image of the femoral head in the hip to determine whether the disease is developing bi-laterally.

Treatment for AVN is recommended based on the stage of the disease coupled with the age of the patient. In Stage I, medication and crutches may be prescribed to provide relief and enable the bone to heal on its own. This treatment may require the patient to be non-weight-bearing for up to six months. It also has a failure rate greater than 80 percent.

Surgical treatment is recommended with a Stage II diagnosis, or very early in a Stage III diagnosis. A procedure known as a core decompression typically involves drilling one large hole in the core of the effected bone, with or without a bone graft, to reduced pressure and improve blood circulation in the hip.

Another surgical option is the vascularized fibular graft, which takes a healthy piece of bone from the fibula, along with the artery or vein, and transplants and reattaches it into the hip, to help healthy bone grow. Recovery can take several months.

Because most patients are diagnosed in late Stage III or IV of the disease, when the bone quality of the femoral head is poor (subchondral fracture) or has collapsed, total hip replacement is the most successful treatment for AVN.

This procedure replaces the damaged bone with artificial parts. Recovery takes about eight weeks.

If left untreated, AVN progresses and results in pain and severe osteoarthritis.

Treatment decisions for AVN ultimately are up to the patient and are based on his or her lifestyle and goals. If you are suffering with hip pain, talk with your primary care doctor about a referral to an orthopedic surgeon.

DiSimone is an orthopedic surgeon with UPMC Susquehanna.

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