Avascular Necrosis

The hip is a ball-and-socket joint made up of the femoral head (the ball) and the acetabulum (the socket).

Most people think of bones as solid structures that simply sit there and do their job.

In reality, bone is living, dynamic tissue.

Just like muscles, skin, and organs, bone depends on a healthy blood supply to receive oxygen and nutrients.

The femoral head has a somewhat unique blood supply compared to many other parts of the body. Because of the way blood vessels travel into the hip, the femoral head can be particularly vulnerable if that circulation becomes disrupted.

When blood flow decreases or stops, the bone may weaken from the inside out.

Initially, the cartilage covering the joint may remain normal. However, as the underlying bone loses strength, the smooth surface can eventually collapse.

Once the ball is no longer perfectly round, pain and arthritis often follow.

In some patients, the cause of AVN is clear.

In in most peole, it seems to appear out of nowhere.

Common causes and risk factors include:

Corticosteroid Use

Long-term or high-dose steroid use is one of the most common risk factors associated with AVN.

Steroids can affect the body’s ability to maintain healthy blood flow within bone tissue.

Excessive Alcohol Use

Heavy alcohol consumption has been linked to AVN and may interfere with blood supply to the femoral head.

Hip Trauma

A hip fracture or dislocation can directly damage the blood vessels that supply the femoral head.

Certain Medical Conditions

Conditions such as sickle cell disease, lupus, clotting disorders, and some autoimmune diseases can increase the risk of AVN.

Previous Cancer Treatments

Certain chemotherapy medications and radiation treatments may contribute to the development of AVN.

Idiopathic AVN

This is the medical way of saying, “we don’t know exactly why it happened.”

Surprisingly, many patients with AVN have no obvious risk factors at all.

Dr. Tauchen often sees patients who are otherwise healthy and active and are understandably frustrated when they learn they have AVN despite doing everything “right.”

Unfortunately, AVN is one of those conditions that sometimes develops without a clear explanation.

The symptoms of AVN can be remarkably similar to hip arthritis.

Many patients initially assume they pulled a muscle, overdid it at the gym, or slept in a strange position.

Common symptoms include:

Groin Pain

Pain deep in the groin is the most common symptom.

Patients frequently point directly to the front of the hip when describing their discomfort.

Pain with Walking

Activities that place weight on the hip often become increasingly uncomfortable.

Limping

As pain worsens, many patients begin to favor one side.

Reduced Range of Motion

The hip may feel stiff or tight, making it more difficult to bend, rotate, or perform everyday activities.

Pain with Exercise

Cycling, running, golfing, and other activities may become increasingly limited.

Pain at Rest

As AVN progresses, symptoms may begin occurring even while sitting or resting.

One clue that sometimes raises suspicion for AVN is the age of the patient.

While arthritis often develops later in life, AVN frequently affects younger adults who are otherwise active and healthy.

When a relatively young patient develops significant hip pain without an obvious explanation, AVN is often one of the conditions Dr. Tauchen considers.

Diagnosing AVN starts with a detailed history and physical examination.

Dr. Tauchen evaluates a patient’s symptoms, medical history, risk factors, and physical function.

X-rays are often the first imaging study obtained.

In the early stages of AVN, however, X-rays can appear surprisingly normal.

This is one reason the diagnosis is sometimes delayed.

When AVN is suspected, an MRI is often the most useful imaging test. MRI scans can identify changes within the bone long before those changes become visible on standard X-rays.

As the condition progresses, X-rays may begin to show flattening, collapse, or arthritis within the hip joint.

The stage of AVN plays an important role in determining treatment options and helping patients understand what to expect moving forward.

One of the biggest challenges with avascular necrosis is that symptoms often begin long before major changes appear on X-rays.

The earlier AVN is identified, the more treatment options may be available.

Unfortunately, once the femoral head collapses and arthritis develops, treatment most often become surgical.

Once the normally round femoral head loses its shape, the joint no longer functions smoothly.

For that reason, early evaluation is important when persistent hip pain does not improve as expected.

The goal is not simply to diagnose a condition. The goal is to preserve function, reduce pain, and help patients return to the activities they enjoy.

Whether that means maintaining an active lifestyle, keeping up with family, returning to sports, or simply walking without pain, Dr. Tauchen believes every treatment plan should focus on helping patients get back to living their lives rather than organizing their lives around their hip pain.