Feasibility of Osseous Landmarks for ACL Reconstruction-A Macroscopic Anatomical Study

Featured Application Osseous landmarks are of great importance in the anatomical placement of the graft in ACL reconstruction. Differentiating which of them are more reliable than others thus improves surgical procedures. During knee arthroscopy, easy orientation is important, and possible landmarks include the lateral intercondylar ridge (LIR) and the lateral bifurcate ridge (LBR). The objective was to show the feasibility of the LIR and the LBR as landmarks of the femoral attachment of the anterior cruciate ligament (ACL) among subjects with different levels of training. Thirty-six formalin-phenol-fixed lower extremities were acquired for this prospective macroscopic anatomical study. All soft tissue apart from the ligaments was removed. The two bundles of the ACL and their origins were identified, marked and photographed. Photographs were taken in an arthroscopic setting. An orthopedic surgeon, an anatomist and a medical student identified the ridges. The LIR existed in 80.6% of samples, while the LBR existed in 13.8% of samples. A significant difference existed between the raters in correctly identifying the LIR (p < 0.01). Due to its high frequency, the LIR seems more reliable than the LBR, especially as the LBR has the potential for false positive identification. Nevertheless, as these ridges are not easily discernible, the surgeon has to know the anatomy of the intercondylar notch perfectly to stand even a small chance of correctly placing drill holes in ACL reconstruction. New guidelines for more easily recognizing LIR and LBR arthroscopically are proposed.