Intracapsular pressure in hip synovitis in children.

Scintimetry and intracapsular pressure recordings were performed in 10 painful hips in children. Maximum intracapsular pressures were recorded with the hip in extension or in 90 degrees of flexion. Minimum pressures were recorded with the hip in semiflexion. Extremely high pressures were recorded in extension/maximum internal rotation. In 3 cases the pressure exceeded the estimated systolic blood pressure. There was a close correlation between the volume of aspirated fluid and intracapsular pressure. In a case of septic arthritis, ischemia in the epiphysis was noted scintigraphically. This ischemia was reversed following decompression by aspiration.