Avascular necrosis of femoral head presenting as pathological subcapital neck of femur fracture: An unclassified presentation

Avascular necrosis of femoral head is not an uncommon chronic disorder of hip in adults. The patient presents to the health facility with varied range of symptoms based on the degree of collapse of the head and arthritic changes at hip. Avascular necrosis of hip presenting as subacute condition with pathological sub capital neck of femur fracture has not yet been reported. The commonly used Ficat and Arlet, university of Pennsylvania, association research circulation osseous and the Japanese Investigation Committee on Osteonecrosis do not include such a presentation in the classification nor is management. We report this in an Indian patient aged 42, tailor by occupation presenting with pain and worsening of limp following a squatting event. MRI revealed avascular changes on both hips and sub capital neck of femur fracture on the left. We managed him with an uncemented total hip arthroplasty. The other side was managed conservatively as he was asymptomatic. He had a good result with a Harris hip score of 97 at 7th month follow up.