Most theories concerning osteonecrosis of the femoral head have as their central focus ischemia of bone. This has been difficult to prove because of lack of a method for direct measurement of bone blood flow. The authors evaluated femoral head blood flow in five patients with established femoral head osteonecrosis using laser Doppler flowmetry. Blood flow within the “avascular” segment was lower than that of the normal cancellous bone of the intertrochanteric region. A surrounding zone of hyperemia was noted in four of the five patients. Laser Doppler flowmetry was easy to use and is a reproducible method for direct estimation of bone-blood flow.
* Department of Orthopaedics and Rehabilitation, Vanderbilt University, Nashville, Tennessee; Laboratory for Experimental Surgery, Davos, Switzerland.
** Laboratory for Experimental Orthopaedics Inselspital, Bern, Switzerland.
† Laboratory for Experimental Surgery, Davos, Switzerland; M. E. Muller Institute for Biomechanics, University of Bern, Bern, Switzerland.