Topography of the Femoral Attachment of the Posterior Cruciate Ligament By Osmar V. Lopes Jr., MD, Mario Ferretti, MD, Wei Shen, MD, PhD, Max Ekdahl, MD, Patrick Smolinski, PhD, and Freddie H. Fu, MD Investigation performed at the Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania Background: The success of posterior cruciate ligament reconstruction has varied. The objective of this study was to determine quantitatively and qualitatively the topography and osseous landmarks of the femoral footprints of the anterolateral and posteromedial bundles of the posterior cruciate ligament in order to enhance repair. Methods: Twenty unpaired knees from twenty human cadavers were evaluated. The surface features of the femoral footprints of the anterolateral and posteromedial bundles of the posterior cruciate ligament were studied by means of macroscopic observation and three-dimensional laser photography. Results: We observed, both visually and with three-dimensional laser photography, an osseous prominence located proximal to the femoral footprint of the posterior cruciate ligament in eighteen of the twenty human knees. This osseous landmark, denominated the ‘‘medial intercondylar ridge,’’ determined the proximal border of the posterior cruciate ligament footprint. In eight of the twenty knees, we observed a small osseous prominence between the an- terolateral and posteromedial bundles of the posterior cruciate ligament. A clear change in the slope of the femoral footprint of the posterior cruciate ligament was seen between the anterolateral and posteromedial bundles. The average area of the posterior cruciate ligament footprint (and standard deviation) was 209 ± 33.82 mm 2 , the average area of the anterolateral bundle was 118 ± 23.95 mm 2 , and the average area of the posteromedial bundle was 90 ± 16.13 mm 2 . Conclusions: The femoral footprint of the posterior cruciate ligament has a unique surface anatomy, with a medial intercondylar ridge being frequently present and a medial bifurcate ridge being less frequently present. Clinical Relevance: These anatomical findings may assist surgeons in performing posterior cruciate ligament recon- struction in a more anatomical fashion. T he posterior cruciate ligament is considered to be the primary restraint to posterior knee translation and a secondary restraint to varus, valgus, and external rota- tion of the knee joint 1 . It is composed of two functional bundles: the anterolateral bundle and the posteromedial bundle 2,3 . It has been demonstrated that these two bundles have distinct patterns of tension during the range of motion of the knee joint. The anterolateral bundle is taut near 90° of flexion, and the posteromedial bundle is taut at nearly full extension 2,4 . The success of posterior cruciate ligament reconstruc- tion has been variable 5,6 . Some recent studies have shown that double-bundle posterior cruciate ligament reconstruction can restore knee kinematics better than can single-bundle poste- rior cruciate ligament reconstruction 7-9 . Previous studies have demonstrated that the placement of the femoral tunnel for the posterior cruciate ligament reconstruction is more important than the placement of the tibial tunnel in terms of restoring graft forces 10,11 . Knowledge of the anatomy of the posterior cruciate ligament is crucial to understanding the function of its two bundles as well as to improving the outcome of reconstruction surgery. Although many studies have provided important in- formation about the femoral footprint of the posterior cruciate ligament 2,12-17 , we are not aware of any published detailed an- atomical evaluations of the bone landmarks and topography of Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated. 249 COPYRIGHT Ó 2008 BY THE J OURNAL OF BONE AND J OINT SURGERY,INCORPORATED J Bone Joint Surg Am. 2008;90:249-55 d doi:10.2106/JBJS.G.00448