Avascular necrosis of femoral head (ANFH) is a severely disabling disease characterised by progressive groin pain, a limping gait, leg length discrepancy, collapse of the subchondral bone, limitation of hip function and eventual degeneration of the hip joint requiring total hip arthroplasty. The prevalence of ANFH is unknown but around 15,000 cases are reported in each year in the USA, with most cases being associated with mechanical disruption (hip trauma or surgery), hypofibrinolysis, steroid use, smoking, alcohol intake, haemoglobinopathies and hyperlipidaemia. Familial forms of ANFH appear to be very rare, with only three families identified so far. Age of onset in these familial cases ranges from 15-48 years (as opposed to between 3rd to 5th decade of life for other forms of ANFH). Transmission in familial cases is autosomal dominant and mutations in the type II collagen gene (COL2A1) have been detected in affected family members.
Last update: May 2008