Femoral Tunnel Length in Low Antero-Medial Portal Anatomic ACL Reconstruction
Introduction: Injury to the anterior cruciate ligament (ACL) is the commonest cause of knee instability. Arthroscopic intra articular ACL reconstruction with soft tissue graft is the standard treatment for symptomatic ACL deficient individuals. Non anatomical ACL reconstruction results in loss of range of movement, residual laxity and graft failure. This study aims to make an assessment of femoral tunnel length through a precise low anteromedial portal for the femoral tunnel.
Materials and Methods: A prospective study was conducted on fifty patients who presented with acute or chronic ACL insufficiency to the Orthopaedics Department at Baby Memorial Hospital, Calicut, during the period April 2013 to April 2014. Males aged 18 to 45 were included. Females, revisions, associated fractures, and flexion less than 110 degrees were the exclusion criteria. All patients underwent pre-operative clinical and MRI assessment. Low anteromedial portal was used in all patients for the femoral tunnel.
Results: The mean age of patients was 29.42 years. Most common mode of injury was sports injuries. Femoral tunnel length was between 50 mm and 36 mm with mean length of 42.80 mm and standard deviation of 3.938. Condyle AP diameter and tunnel measurement correlation coefficient value was 0.347 and condyle width and tunnel measurement correlation coefficient value was 0.538.
Conclusion: Low anteromedial portal, placed 5mm medial to the medial border of patellar tendon just above the medial meniscus, can overcome the drawback of short femoral tunnel in anatomical ACL reconstruction. Hyper flexion of the knee is recommended for femoral tunnel drilling. Femoral tunnel length is positively correlated with the lateral condyle width and AP measurement.