Anatomic Single Bundle Anterior Cruciate Ligament Reconstruction Using Two Cross Pins: Cadaveric Study and Clinical Application

Background: Anatomic single bundle is a widely accepted technique for anterior cruciate ligament (ACL) reconstruction. The research question: are transverse pins safe to fix the ACL graft on the femoral side in anatomic single bundle ACL reconstruction? Material and Methods: Ten cadaveric femoral dry bones were tested in this study. Thirty mm long sockets were prepared in the center of the anatomic ACL footprints. Transverse pin guide for soft tissue graft was used to prepare pin sites through the femoral sockets using three different positions. The positions (A) and (B) had a lateral entry point and differ in their inclination in relation to the joint line; while (A) has a 15 ̊ open laterally plane, (B) has a 15 ̊ closed laterally. The last position (C) had a medial entry point for the transverse pins. The relations of the transverse pins to the anatomic landmarks (lateral epicondyle and articular cartilage) in addition to the path of the pins within the femoral sockets were recorded. Results: Pins inserted while the guide in position (A) crossed the center of the femoral sockets and were fully seated within the bone of the distal femur. Distal pins inserted through inclination (B) were found to penetrate the posterior cortex of the distal femur proximal to the lateral femoral condyle. Pins inserted from the medial side (C) achieved central position through the femoral tunnel. The entry point for transverse pins through lateral entry points was very close to the attachment of the lateral collateral ligament at the lateral epicondyle while medial entry point avoided important structures. Conclusion: Transverse pins inserted through the lateral entry point carry the risk of penetrating the posterior cortex of the femur and/or damage the attachment of the lateral collateral ligament. Medial entry point may give a safer approach but needs further adjustments of the guides and clinical trials of the technique.