Bone scintigraphy of hip joint effusions in children.

Thirty-eight children with hip pain of acute onset were studied by bone scintigraphy. Nine patients had diminished radiotracer deposition involving the entire proximal femoral ossification center. This could be related to infarction or compression of the blood supply by a tense joint effusion. Eight of these patients had joint aspiration confirming the presence of an effusion. Five patients had follow-up studies after aspiration, and femoral-head uptake reverted to normal in all but one which subsequently proved to be infarcted. A photopenic zone was seen on blood pool images in 10 patients, many of whom were also aspirated of fluid. Bone scintigraphy is useful in the diagnosis of joint effusions and can give information as to the state of perfusion of the femoral head. Follow-up studies after aspiration can differentiate infarction from reversible ischemia.