What is Avn

Avascular Necrosis (AVN) also called Osteonecrosis is the death of bone tissue due to lack of blood supply. When AVN occurs in hip joint, the top of the femoral head (the ball point) collapses and begins to flatten. The flattening creates a situation where the ball no longer fits to the Hip Joint socket and the joint begins to wear itself out. This condition if not treated leads to bone collapse in 2 years.
Avascular Necrosis (AVN) is a disease that may affect several different bones as a result of temporary or permanent loss of the blood supply to these bones. High risk includes who have taken large doses of steroids, alcoholics, certain fractures of the hip, Sickle cell anemia or other blood conditions, excessive smoking.
Blockage of blood vessel leading to a decreased blood flow to the bone triggers early changes in bone leading to Avascular Necrosis (AVN). Some medications such as corticosteroids can reduce the bone blood flow by increasing fatty marrow and the formation of fatty substance. Bone gets weaker and brittle further and collapse of femoral head. 
The femoral head is most commonly affected by this disease. Initially, patients are asymptomatic but in time Avascular Necrosis (AVN) leads to joint destruction requiring surgical treatment and in later stages total hip replacement. Although treatment has been facilitated by using international classification system, diagnosed through MRI and more aggressive surgical management, no universally satisfactory therapy has been developed even for early disease. 
Patients with Avascular Necrosis (AVN) of the femoral head often report groin or hip pain that can radiate to the buttocks, antero-medial thigh, or knee that is exacerbated by weight bearing and sometimes by coughing. The pain may initially be mild but progressively worsens over time and with use. Eventually, the pain is present at rest and may be present or even worsen at night; in which case, it may be associated with morning stiffness. 
Bone defects are a serious illness that can result after a pathological process has destroyed vital components of the bone. Most commonly the causative event is extensive trauma and subsequent infection. There are a variety of bone defects like traumatic fractures, nonunion fractures where the bone is unable to heal completely leaving the patient in pain and lifelong suffering. Variable methods of treating bone defects are decided according to the patient’s age general condition and degree of damage.