Avascular Necrosis

Avascular necrosis can result from a traumatic injury such as hip fracture or dislocation that disrupts the blood vessels or bone marrow supplying the joint. When not caused by injury, AVN is believed to result from the combination of genetic predisposition as well as metabolic and mechanical factors that affect blood supply to the joint. Common metabolic risk factors for hip AVN include alcoholism, the prolonged use of steroids, chemotherapy and immune suppressing drugs, lupus, sickle cell anemia and other hereditary disorders. However, in about 20% of cases the cause is unknown.

Lack of a blood supply to the head of the thigh bone (femur) can disrupt mature bone cell health & turnover which in turn can lead to the fracture and collapse of the femoral head. Subsequently, the articular cartilage at the head of the femur can also collapse leading to disabling arthritis of the hip joint sometimes necessitating urgent orthopedic intervention.

This condition often develops in stages over the course of months to a year. The primary symptom is pain in the groin, thigh, or buttocks region. As the disease progresses it can become difficult to move the joint and bear weight on the affected hip due to collapse of the femoral head. Two-thirds of patients report pain at rest and one third report pain when lying down to sleep at night.

The expert clinicians at LALL Orthopedics ⁺ will conduct a comprehensive exam including a thorough review of your medical history to determine metabolic causes, review imaging findings such as x-rays and perform a detailed physical exam. An MRI may be useful to evaluate the amount of affected bone and reveal early osteonecrosis on the opposite hip even before symptoms develop.

Early diagnosis is important for disease management, but most patients have little to no symptoms in the early stages and do not present for evaluation until significant damage has already occurred. Each patient with symptomatic avascular necrosis (AVN) of the hip is unique requiring an individualized treatment plan. The goal is to preserve the biological hip joint for as long as possible taking into consideration the patient’s quality of life, age, mobility, occupation and lifestyle.

The primary treatment options for hip AVN include nonoperative conservative treatment, joint-preserving procedures, and total hip replacement. Nonsurgical treatment can help treat pain and slow progression. For patients with a diagnosis of early-stage necrosis, hip-preserving procedures can prevent the collapse of bone.

Nonsurgical treatment includes physical therapy, the use of assistive devices like a cane, and anti-inflammatory treatments, which may provide temporary relief of symptoms.

Early-stage surgical options include hip preservation procedures that help restore bone health and blood supply, thereby slowing, sometimes reversing, disease progression. Recovery from these procedures requires a few weeks to months, however, once completed patients can expect full unassisted return to function and complete pain relief.

• Core decompression: a minimally invasive 10-15 minute outpatient surgical procedure used to relieve pressure and create channels for new blood vessel growth. It has been clinically proven to be very successful in early-stage AVN disease and can prevent progression to severe arthritis.

Advanced stage AVN requires open surgical intervention. Options include:

• Vascularized bone grafting: A segment of bone is retrieved from the fibula (a lower leg bone) with its blood supply and transplanted into the head of the thigh bone. This procedure restores the bone scaffold with vascular blood supply.
• Osteotomy: This procedure is utilized to remove diseased bone followed by bone grafting. This procedure can delay the need for a total hip replacement.
• Total hip replacement (THA): removal and replacement of the head of the thigh bone and socket to completely reconstruct the hip joint thereby curing the hip of AVN. This definitive procedure has been clinically proven as the gold standard for hip pain relief with an extremely high success rate and low rate of complications.