ULTRASOUND OF THE PAINFUL HIP IN CHILDREN

The condition of “irritable hip” is well recognised in children and is probably the result of a transient synovitis of uncertain origin. It usually occurs in the under-10 years age group and is a benign condition which settles with bed-rest and analgesia. The synovitis causes an effusion and the diagnosis of “irritable hip” is retrospective when the effusion and symptoms have resolved. The radiological signs of irritable hip are non-specific. “Stand-off” of the femoral head from the acetabulum may occur in children with an effusion, but rotation of the femur can also produce this sign. Evidence of soft-tissue, or capsular, displacement has been shown to be more of a radiological artefact than a true sign (Brown, 1975). This report suggests that ultrasound is a useful additional method of imaging the hip joint in children with a painful hip.