ACL footprint size is correlated with the height and area of the lateral wall of femoral intercondylar notch

The purpose of this study was to reveal the correlation between the size of the native anterior cruciate ligament (ACL) footprint and the size of the lateral wall of femoral intercondylar notch. Eighteen non-paired human cadaver knees were used. All soft tissues around the knee were resected except the ACL. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the periphery of the ACL insertion site was outlined on both the femoral and tibial sides. An accurate lateral view of the femoral condyle and the tibial plateau was photographed with a digital camera, and the images were downloaded to a personal computer. The size of the femoral and tibial ACL footprints, length of Blumensaat's line, and the height and area of the lateral wall of femoral intercondylar notch were measured with Image J software (National Institution of Health). The sizes of the native femoral and tibial ACL footprints were 84 +/- A 25.3 and 144.7 +/- A 35.9 mm(2), respectively. The length of Blumensaat's line and the height and area of the lateral wall of femoral intercondylar notch were 29.4 +/- A 2.8 mm, 17.1 +/- A 2.7 mm, and 392.4 +/- A 86 mm(2), respectively. Both the height and the area of the lateral wall of femoral intercondylar notch were significantly correlated with the size of the ACL footprint on both the femoral and tibial sides. For clinical relevance, the height and area of the lateral wall of femoral intercondylar notch can be a predictor of native ACL size prior to surgery. However, the length of Blumensaat's line showed no significant correlation with native ACL size.