Background: It has been previously described that with increasing knee flexion angles, the popliteal artery tends to rest further away from the posterior tibial cortex, thus offering a safer position for procedures about the knee. These studies did not incorporate the use of a surgical thigh tourniquet, something commonly used by orthopedic surgeons. The purpose of this study was to evaluate the axial distance of the popliteal artery from the tibial PCL insertion and the posterior tibial cortex, with and without an inflated thigh tourniquet.
Methods: Institutional Review Board approval was obtained. Using 3T magnetic resonance imaging, six volunteer knees were evaluated in both full extension and 90 degrees of flexion, with and without a thigh tourniquet inflated to 200 mmHg. Axial images at the level of the PCL tibial insertion were obtained. The popliteal artery’s distance from the PCL tibial insertion and the posterior tibial cortex at this level were calculated.
Results: From the posterior tibial cortex, the mean distance at 0 degrees was 6.88 mm, and at 90 degrees was 9.43 mm. With tourniquet use, there was a significant decrease in the distance of the popliteal artery from the posterior tibial cortex in both 0 degrees and 90 degrees of flexion, 6.17 mm and 7.95 mm respectively. There was no significant change in distance with tourniquet use from the PCL tibial insertion.
Conclusion: The results of this study suggest that with an inflated thigh tourniquet, the popliteal artery rests closer to the posterior tibial cortex at the level of the PCL insertion than previously described. The posterolateral location of the artery relative to the PCL may suggest why we did not find any significant change. Our study found similar distances without tour- niquet use to similar previous studies.
