Size correlation between the tibial anterior cruciate ligament footprint and the tibia plateau

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 tibia plateau.

Twenty-four 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, and anterior-posterior (AP) and medial-lateral (ML), lengths of the tibia plateau and area of tibia plateau were measured with Image J software (National Institution of Health).

The sizes of the native femoral and tibial ACL footprints were 72.3 ± 24.4 and 134.1 ± 32.4 mm(2), respectively. The AP lengths of the whole, medial and lateral facet of the tibia plateau were as follows: 44.5 ± 4.1, 40.8 ± 4.1 and 36.8 ± 4 mm, respectively. The ML length of the tibia plateau was 68.3 ± 5.5 mm. Total area of tibia plateau was 2,282.9 ± 378.7 mm(2). The AP length of the lateral facet of the tibia plateau (Pearson's correlation coefficient = 0.508, p = 0.011) and the total area of tibia plateau (Pearson's correlation coefficient = 0.442, p = 0.031) were significantly correlated with the size of the tibial ACL footprint.

For clinical relevance, the AP length of lateral facet of the tibia plateau and total area of tibia plateau are significantly correlated with the size of the tibial ACL footprint. It might be possible to predict the size of the ACL measuring these parameters.