SOFT-TISSUE BLOOD-FLOW FOLLOWING REAMED VERSUS UNREAMED LOCKED INTRAMEDULLARY NAILING - A FRACTURED SHEEP TIBIA MODEL

A study was performed to compare the effects of reamed versus unreamed locked intramedullary nailing on soft-tissue blood flow in a fracture d sheep tibia model. After creation of a standardized short spiral fra cture, each tibia was stabilized by insertion of a locked intramedulla ry nail, Ten animals were randomized into two groups: one that had rea ming prior to nail insertion and one that did not. Blood flow was meas ured in real time, using laser Doppler flowmetry. Skin and muscle perf usion measurements were made at three locations (proximal diaphysis, f racture site, and distal diaphysis) and at five time intervals (postfr acture; postnail insertion; and at 2-week, 6-week, and 12-week follow- ups). All animals were sacrificed at 12 weeks postoperatively. Muscle blood flow remained elevated longer in the reamed group than in the un reamed group, following completion of the procedure, Muscle perfusion was significantly greater in the reamed group than in the unreamed gro up (p < 0.033) and was significantly greater than skin perfusion at 2 weeks (p < 0.024). There was no difference in skin perfusion between t he reamed and unreamed groups at any time interval. The study demonstr ates that muscle perfusion is altered following reamed and unreamed in tramedullary nailing. The findings demonstrate the change in blood flo w in the surrounding soft-tissue envelope during the process of revasc ularization, following devascularization of a segment of tibial cortex by intramedullary nailing.