The 'cold hip' sign on bone scan. A retrospective review.

The "cold hip" sign on bone scan is often seen in patients referred with irritable hip. This sign is due to fluid in the hip joint under pressure causing impaired perfusion of the structures within the joint capsule. In a retrospective review, 22% of patients with this sign on bone scan were found to have septic arthritis at surgery. This fact would appear to justify surgical drainage or aspiration of any hip showing this sign on scan. An attempted follow-up study through the medical records was incomplete because of the short follow-up on most patients. The possibility that temporary impairment of blood supply to the head of the femur causes long-term damage to the hip is unanswered on this study, and a long-term recall follow-up study is underway.