Blood flow rates in canine cortical and cancellous bone measured with 99Tcm-labelled human albumin microspheres.

Regional differences in bone blood flow rates in the femur and the tibia of dogs were measured with 99Tcm-labelled microspheres. The measurements show an average flow rate of 3.7 ml (100 g)-1 x min-1 in cortical bone. A more rapid pace was found in red marrow containing areas, with an average flow rate in the femoral head of 19.7 ml blood (100g)-1 x min-1, and in the femoral neck of 50.3 ml blood (100 g)-1 x min-1. In the calcar femorale the average flow rate was 9.0 ml (100 g)-1 x min-1, and compared to cortical flow a positive correlation between strain and perfusion seems obvious. No difference between cortical bone in tibia and femur was found. The flow rates in the red marrow of the femoral neck are remarkably high, but the flow in the cortical bone is relatively low. It is concluded that handling of fragments of cortical bone and the associated soft tissue is presumably critical, and that the surgical technique has to be quite gentle to obtain optimal conditions for fracture healing.