Haemodynamic changes in the rat femur and tibia following femoral vein ligation.

Interference with venous outflow from a limb to stimulate fracture repair and bone growth has a long history, and its beneficial effects have been confirmed by many experimental and clinical studies. With the development of fracture fixation systems, the therapeutic use of circulatory intervention became redundant. Recently, a venous tourniquet effect has been cited to explain the enhancement of bone healing observed after fracture fixation with the Aircast system. As bone appears to be altered by venous stasis, it is important to characterise the vascular perturbations leading to these changes. Previous studies have often given conflicting results. This study investigated the short and long term haemodynamic effects of femoral vein ligation. Changes in blood flow rate and blood volume in the distal femur and proximal tibia of the rat were examined at 6 h and 1, 3 and 7 d following unilateral femoral vein ligation, and at 8 and 16 wk. Blood flows and volumes were generally reduced in the ligated limb 6 h after femoral vein ligation. This initial depression was followed by a relative increase (comparing the ligated limb with the contralateral unoperated bone) in blood volume during the 1st week. A significant relative reduction in epiphyseal vascular space was observed after 16 wk. A sustained reduction of arterial input to whole femora and tibiae was present in the ligated limb throughout the investigation although, for the cancellous knee joint epiphysis of the tibia, a localised relative increase in flow was apparent during the 1st week, again comparing the ligated limb with the nonligated contralateral bone.(ABSTRACT TRUNCATED AT 250 WORDS)