Location of femoral/tibial tunnels in anterior cruciate ligament reconstruction and their impact on graft integrity: Magnetic resonance imaging review

Context: Despite advances in surgical techniques for anterior cruciate ligament (ACL) repair, a significant proportion of patients encounter persisting pain/instability of the knee postoperatively. Objectives: To assess the location of femoral/tibial tunnels on magnetic resonance imaging (MRI) and to correlate the findings with the ACL graft integrity/graft-related complications. Study Design/Settings: This was a cross-sectional study done at Burjeel Medical Centre, Muscat, Oman. Materials and Methods: The study period was between November 2015 and June 2017 on Philips Ingenia 1.5 Tesla MRI machine. A total of 30 male patients, age ranged from 20 to 43 years who presented with knee pain/instability 1 year postreconstruction of ACL, were recruited for the study. Results: Of 30 cases, 10 (33.33%) patients had an intact graft on MRI. Of the remaining 20 patients, graft impingement was noted in 15 patients (50%), graft tear in 3 cases (10%), and graft stretching with abnormal high T2 signal in the remaining 2 cases (6.67%). Associated findings of focal arthrofibrosis in the anterior knee joint space and tibial tunnel cysts were encountered in few patients who were not dealt with in this study. Out of 20 patients with graft abnormality, femoral tunnel was abnormally located in 3 (15%), tibial tunnel was located anterior to the MRI equivalent of Blumensaat's extension line partly or completely in 16(80%) and both tunnels were normally located in 1(5%). Conclusion: The location of the femoral/tibial tunnels is the most important determinant factor of postoperative graft integrity in ACL reconstruction patients.