Checkpoints for judging tunnel and anterior cruciate ligament graft placement.

This article examines how the relationship between sagittal and coronal anatomy, anterior cruciate ligament (ACL) graft dimensions, and tibial and femoral tunnel placement affects the posterior cruciate ligament (PCL) and roof impingement, and their undesirable clinical consequences of motion loss and instability. Based on these interrelationships, a variety of checkpoints are defined that can be used intraoperatively to determine whether placement of the tibial tunnel guidewire avoids PCL and roof impingement, and whether placement of the femoral tunnel guidewire avoids PCL impingement with either transtibial or transportal techniques. A simple, 3-dimensional tibial drill guide that consistently places the tibial tunnel correctly without PCL and roof impingement so the femoral tunnel, when drilled through the tibial tunnel, restores the normal tension pattern in the ACL graft also is described. Arthroscopic and radiographic checkpoints that assess the final placement of the ACL graft and tibial and femoral tunnels are discussed.