Proximity of the posterior cruciate ligament insertion to the popliteal artery as a function of the knee flexion angle: Implications for posterior cruciate ligament reconstruction

Purpose: The purpose of this study was to determine if an optimal knee flex ion angle existed that would minimize the risk of neurovascular injury from the passage of transtibial hardware during posterior cruciate ligament (PC L) reconstruction. Type of Study: Cadaveric. Materials and Methods: Fourtee n fresh-frozen cadaveric knees were mounted in a Plexiglas apparatus that c ould be set at 5 different knee flexion angles (0 degrees, 45 degrees, 60 d egrees, 90 degrees, and 100 degrees) while joint distention was maintained. Each knee underwent magnetic resonance imaging in the axial and sagittal p lanes at each of the 5 flexion angles to determine the distance between the PCL tibial insertion and popliteal artery. Results: The mean distance, ove r all 5 flexion angles, between the PCL insertion and the popliteal artery in the axial plane was 7.6 mm, whereas the mean distance in the sagittal pl ane was 7.2 mm. There was a significant: increase in distance with progress ive flexion in both planes. Maximum mean distances were noted at 100 degree s of flexion in both the axial (9.9 mm) and sagittal (9.3 mm) planes. An ar tificial line mimicking the path of a transtibial drill passed through the popliteal artery in 10 of 10 cases at the 0 degrees, 45 degrees, 60 degrees , and 90 degrees angles, and in 6 of 10 cases at the 100 degrees angle. Con clusions.: The results of this study suggest that increasing knee flexion r educes, but does not completely eliminate, the risk of arterial injury duri ng arthroscopic PCL reconstruction.