Avascular necrosis, also known as AVN and osteonecrosis, is a disease caused from inadequate blood supply to the bone which leads to bone death.  The disease is most common in adults aged 30-60 but can also occur in children, mainly from cancer therapy.  In the hip, the lack of blood supply causes death of the bone cells of the femoral head and may eventually result in collapse of the bone.  It can affect one or more bones and if left untreated, it can lead to destruction of the adjacent bones, tissues, and joints

Causes

Avascular necrosis is caused by insufficient blood supply to the bone leading to a loss of minerals and nutrients which normally keep bones healthy

Common causes of avascular necrosis in children include:

• Trauma – dislocation or bone fractures can injure blood vessels
• Long/Short term high dose steroid treatment
• Cancer treatments – radiation or chemotherapy
• Blood disorders – such a sickle cell disease and leukemia

Symptoms

In the early stages of avascular necrosis, there are no symptoms.  As the disease progresses, the patient may experience the following symptoms:

• Gradual increase in joint pain
• Pain occurring even at rest
• Limping and groin pain if the hip joint is involved
• Restricted range of motion

Diagnosis

A detailed medical history and physical examination will be performed at your visit.  Further diagnostic procedures may be ordered:

• Imaging studies – such as X-ray, magnetic resonance imaging (MRI), and computed tomography (CT) scan can determine the extent of bone damage and if the disease has spread to the surrounding tissues
• Bone scan – A small amount of radioactive material is injected into a blood vessel and collects in the bone.  A special camera takes pictures of the affected areas of bone
• Biopsy – A tissue sample is removed and sent for microscopic examination to rule out the presence of cancer cells in the bone

Nonsurgical Treatment

• Medications – Non-steroidal anti-inflammatory drugs (NSAIDs) may be prescribed to relieve pain.  Children with blood clotting diseases will be given blood thinners (anti-coagulants) to dissolve the clots
• Reduced weight bearing – rest and use of crutches may reduce weight on the affected bone in order to promote natural healing. 

Surgical Treatment

• Core decompression – In this surgery, the inner part of the bone (diseased bone) is removed thereby reducing pressure within the bone.  This increases the blood flow and helps form new blood vessels.  This procedure relieves pain and slows the progression of bone and joint destruction and is best performed in the early stages of AVN
• Arthroplasty or total joint replacement – This procedure is performed only when all other treatments are unsuccessful or when there is complete collapse of the bone with resulting joint destruction.  The joint is replaced with artificial implants
• Vacular grafting – Bone along with blood vessels and arteries are surgically transplanted to the affected bone providing an immediate blood supply to the area
• Bone grafting – This surgery replaces diseased bone with healthy bone, taken from the patient or from a bone bank, to increase blood supply to the area