Hemodynamics of the femoral head

We have determined the pressure-flow relationships of the canine femoral head during venous tamponade of the hip capsule. Intra-osseous pressures were determined before and after infusion of the joint with saline solution to a pressure of sixty-five centimeters of water. Femoral head blood flow was simultaneously determined by the indicator-dilution technique utilizing isotopically labeled microspheres. In puppies, pressure in the femoral head rose 248 per cent while flow dropped by 60 per cent after inflation of the capsule. In adults, no statistically significant change in either pressure or flow was seen. Thus, in the immature animal, venous tamponade results in increased pressure and decreased blood flow. In the mature animal, venous tamponade does not alter intra-osseous pressures or blood-flow rates due to the intact intramedullary venous drainage of the adult femoral head.