AVN Hip (Avascular Necrosis) (Osteonecrosis)

Overview

Avascular necrosis is basically death of the bone. One of the common areas it affects is the hip joint. The upper portion of the thigh bone is in the shape of a ball and forms a joint with the socket of the pelvic bone. These to bone ends together is called hip joint. The ball or head of the thigh bone (femur) has got the blood supply in a reverse fashion from the neck upwards. The blood vessels around the neck of the femur form a ring from which blood vessels travel upwards to the head of the femur. When the pressure increases in the capsule of the joint, it obstructs the blood supply. This leads to the death of the bone in the head area which is called necrosis. Necrosed bone will not be able to support the cartilage (the lining of the joint) and hence starts collapsing. As the bone collapses the shape of the ball starts changing. This leads to incongruence of the joint leading to arthritis. 

Causes

  • Joint injury

  • Fat deposition

  • Cholesterol

  • Smoking

  • Alcohol

  • Obesity

  • Usage of steroids and certain other medications

  • Sickle cell disease

Symptoms

Early stages of AVN are often without any symptoms. As the condition worsens one may end up having pain on walking and also notice the stiffness. Pain can gradually worsen and eventually lead to pain at night as well. Pain is commonly felt in the groin area or in the C shaped area around the hip. In some the pain can radiate to the knee.

When to see the Doctor?

This is one condition where the sooner the diagnosis is made the better. In majority of patients, the condition gradually deteriorates. Advanced AVN leads to collapse of the bone and change in the shape of the bone. Once these irreversible changes occur the conservative management may not be ideal for those patients.