The Journal of Bone and Joint Surgery, Vol 63, Issue 3 442-448, Copyright © 1981 by Journal of Bone and Joint Surgery, Inc
Hemodynamics of the femoral head
WJ Launder, DS Hungerford and LH Jones
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.
CLINICAL RELEVANCE: In the immature individual, venous tamponade may well
be involved in the development of Legg-Perthes disease. A bout of
nonspecific synovitis may elevate intracapsular pressure sufficiently to
obstruct venous outflow. This creates an increase in intra-osseous pressure
and a decrease in femoral head blood flow. Hemodynamic changes of this
magnitude have not been shown to induce Legg-Perthes disease; however, a
strong suspicion exists that such alterations may be linked to the disease.
In the adult, venous tamponade probably is not involved in the pathogenesis
of avascular necrosis. The maintenance of intramedullary venous drainage of
the epiphysis into the metaphysis may account for the fact that vascular
necrosis of the femoral head rarely develops in adult patients with
osteoarthritis or rheumatoid arthritis plus an inflammatory synovitis of
the hip.