Reperfusion pattern of the immature femoral head after critical ischemia -A microsphere study in pigs

The topographic reperfusion pattern of the femoral head after critical isch emia has not yet been investigated. We determined the blood flow of the por cine hip regions with the femoral head epiphysis divided into 24 subregions by the tracer microsphere technique. Blood flow was measured under steady- state conditions, at the end of a 6-hour increase in intracapsular hip join t pressure to 250 mm Hg, and 4 hours after release of the joint tamponade. Total femoral head epiphyseal blood flow decreased with ischemia and regain ed steady-state perfusion after tamponade. The reperfusion pattern of the f emoral head epiphysis appeared identical with that of the steady state befo re ischemia. However, 2 of the II experimental epiphyses remained ischemic in the reperfusion phase. We conclude that hip joint tamponade above the arterial pressure level for 6 hours causes global ischemia in the femoral head epiphysis in the immatur e pig, without regional differences in reperfusion, and that reperfusion oc curs at a level like that of the steady state before ischemia.