Loss of Motion Due to Graft Impingement (Roof Impingement and Posterior Cruciate Ligament Impingement)

This article discusses how to prevent loss of extension from roof impingement and loss of flexion from posterior cruciate ligament impingement while performing an anterior cruciate ligament reconstruction. The definition, complications, and diagnosis of roof and posterior cruciate ligament impingement are discussed. The rationale and a proven technique for placing the tunnels with the transtibial technique in which the tibial tunnel is drilled first and the femoral tunnel is drilled through the tibial tunnel is presented. Clinical and biomechanical studies show that the key tunnel in the transtibial technique is the tibial tunnel. These studies also show that correct placement of the tibial tunnel in the sagittal and coronal planes, and subsequent drilling of the femoral tunnel through the tibial tunnel, avoids extension loss from roof impingement, avoids flexion loss from posterior cruciate ligament impingement, replicates the tension pattern of the intact anterior cruciate ligament, and restores anterior laxity to the reconstructed knee.