A patient of nephrotic syndrome taking steroids for 6 years presented with a limp gait and of limitation of abduction and internal rotation. He most probably has:

Ans. is 'b' ie Avascular necrosis of hip "The femoral head is the commonest site of symptomatic osteonecrosis (avascular necrosis), mainly because of its peculiar blood supply which renders it vulnerable to ischemia.Non traumatic osteonecrosis is seen in association with infiltrative disorders of the marrow, Gaucher's ds Sickle cell ds. coagulopathies, Caisson's ds., SLE and more commonly - high dosage of corticosteroids administration and alcohol abuse."Clinical features of avascular necrosis of hip"The presenting complaint is usually pain in the hips (or in over 50% of cases, both hips), which progresses over a period of 2-3 yrs to become quite severe."On examination the pt. walks with a limp and may have a positive Trendelenburg's sign.The thigh is wasted and the limb may be 1-2 cm short.Movements are restricted, particularly abduction and internal rotation."A characteristic sign is a tendency for the hip to twist into internal rotation during passive flexion. This corresponds to Sectorial sign in which, with the hip extended, internal rotation is almost full, but with the hip flexed it is grossly restricted."