Femoral tunnel in revision anterior cruciate ligament reconstruction.

The failure rate after anterior cruciate ligament (ACL) reconstruction performed by expert surgeons is estimated to be in the range of 10-15%, and only 60% of patients undergoing this surgery are able to resume sporting activities comparable to those they engaged in prior to the traumatic incident. Incorrect femoral tunnel placement is one of the main causes of failed ACL reconstruction and this must be remembered when undertaking revision surgery. There are various possible errors that can be committed and, to plan revision surgery correctly, it is fundamental to study the position of the existing femoral tunnel(s) both on classic anteroposterior and lateral plain radiographs and on computed tomography scans with frontal, sagittal, and coronal sections, and also using three-dimensional reconstruction. In-depth anatomical knowledge and familiarity with the various possible surgical techniques are also mandatory for a successful surgical outcome.