Avascular Necrosis (AVN)


What is avascular necrosis? 

Avascular necrosis (AVN) of the hip is a painful condition that occurs when the blood supply to the head of the femur is disrupted. Because bone cells need a steady supply of blood to stay healthy, AVN can ultimately lead to destruction of the hip joint and severe arthritis. Although it can occur in any bone, osteonecrosis most often affects the hip.


What are the symptoms? 

AVN of the hip develops in stages. Many people have no symptoms in the early stages of avascular necrosis, but as the disease develops over time, hip pain is typically the first symptom. This may lead to a dull ache or throbbing pain in the groin area. As the disease progresses, it typically becomes more difficult to stand and put weight on the affected hip, and moving the hip joint becomes very painful. Later, as the surface of the femoral head collapses, the entire joint becomes arthritic, leading to loss of motion and stiffness.


How is AVN diagnosed?

Imaging tests are important in determining the diagnosis of avascular necrosis, as well as the severity of its progression. X-rays can reveal bone changes that occur in the later stages of avascular necrosis, but in the condition's early stages, x-rays usually appear normal. MRI scans have the ability to detect early changes in the bone that may not show up on other types of imaging, and may also show early AVN that has yet to cause symptoms. Dr. Potts may order an MRI of your hip in order to see more detailed images and evaluate how much of the bone is affected by the disease. 

It may take anywhere from months to years for the avascular necrosis to progress, so it is important to diagnose it as soon as possible. Studies show that early treatment is associated with better outcomes.


What is the treatment for AVN?

Although non-surgical treatment options — such as activity modification, anti-inflammatory medications, and limiting weight bearing with crutches  — can help relieve pain and slow the progression of the disease, the most successful treatment options are surgical. Patients with AVN that is caught in the very early stages (before the femoral head collapses) are potential candidates for hip-preserving procedures, such as a core decompression and bone grafting. If the disease has advanced to the point where the femoral head has already collapsed, the most successful treatment is total hip replacement.