BLOOD-FLOW TO THE IMMATURE HIP - ULTRASONIC MEASUREMENTS IN PIGS

We quantitatively analyzed blood flow through the major arteries suppl ying the pig's femoral head during various hip positions and following ligation of Various vessels in order to identify the vascular abnorma lities which may be responsible for the development of avascular necro sis during the treatment of developmental dysplasia of the hip. Our fi ndings reveal that a decrease in total brood flow to the femoral head occurs when the hip is held in the frog leg position with ligation of the deep femoral artery and proximal ligation of the lateral femoral c ircumflex artery, and ligation of the deep femoral artery, together wi th the lateral femoral circumflex artery proximally. In contrast, neit her distal ligation of the medial femoral circumflex artery nor latera l femoral circumflex artery alone nor holding the hip in the Lange pos ition caused a statistically significant decrease in total flow. We al so observed a unique steal effect on total proximal femoral blood flow , with the hip held in the frog leg position. In 4 of 7 pigs, we found a reversal of flow in the medial femoral circumflex artery.