Three-dimensional characterization of the femoral footprint of the posterior cruciate ligament.

Abstract

The purpose of this study was to define an anatomic standard for the femoral footprint of the posterior cruciate ligament (PCL) based on 3-dimensional (3D) surface reconstructions of computed tomography (CT) scans of cadaveric knees. The femoral insertion of the PCL was identified and marked with drill holes in 7 cadaveric knees. CT scans were performed on each specimen, and 3D computer models were generated. The distance from the condyle edges to the margins of the footprint were referenced to the total condylar size parallel and perpendicular to the femoral axis and intercondylar notch. The mean ratio of the anteroposterior width of the medial femoral condyle referenced parallel to the intercondylar notch measured 0.08 ± 0.02 for the anterior border, 0.60 ± 0.08 for the posterior border, 0.16 ± 0.05 for the proximal border, and 0.44 ± 0.06 for the distal border. The mean ratio of the superior-inferior height of the medial femoral condyle with respect to the apex of the intercondylar notch corrected and referenced perpendicular to the intercondylar notch measured 0.14 ± 0.04 for the anterior border, 0.44 ± 0.07 for the posterior border, 0.03 ± 0.02 for the proximal border, and 0.56 ± 0.07 for the distal border. This cadaveric study provides an anatomic reference for mathematical analysis of the femoral PCL footprint using CT-based 3D topographic modeling. The average PCL center point is located 25% down from the roof of the notch and 38% from anterior to posterior from the anterior condyle with regard to total medial femoral condyle length. This study provides a standard of measurement for future studies that use advanced imaging to evaluate the accuracy of PCL reconstruction.