Measurement of the Whole and Midsubstance Femoral Insertion of the Anterior Cruciate Ligament: The Comparison with the Elliptically Calculated Femoral Anterior Cruciate Ligament Footprint Area

Abstract

Purpose:The purpose of this study was to measure the detailed morphology of the femoral anterior cruciate ligament (ACL) footprint. The correlation and the comparison between the measured area and the area which mathematically calculated as elliptical were also evaluated.Materials and Methods:Thirty nine nonpaired human cadaver knees were used. 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 whole footprint and the midsubstance insertion. Lateral view of the femoral condyle was photographed with a digital camera, and the images were downloaded to a personal computer. The area, length, and width of the femoral ACL footprint were measured with Image J software (National Institution of Health). Using the length and width of the femoral ACL footprint, the elliptical area was calculated as 0.25 π (length × width). Statistical analysis was performed to reveal the correlation and the comparison of the measured and elliptically calculated area.Results:The sizes of the whole and midsubstance femoral ACL footprints were 127.6 ± 41.7 mm2 and 61 ± 20.2 mm2, respectively. The sizes of the elliptically calculated whole and midsubstance femoral ACL footprints were 113.9 ± 4.5 mm2 and 58.4 ± 3 mm2, respectively. Significant difference was observed between the measured and the elliptically calculated area. In the midsubstance insertion, significant correlation was observed between the measured and the elliptically calculated area (Pearson's correlation coefficient = 0.603, P = 0.001). However, no correlation was observed in the whole ACL insertion area.Conclusion:The morphology of the femoral ACL insertion resembles an elliptical shape. However, due to the wide variation in morphology, the femoral ACL insertion cannot be considered mathematically elliptical.

The morphology of the femoral footprint of the anterior cruciate ligament changes with aging from a large semicircular shape to a small flat ribbon-like shape

“…After the evaluations were concluded, the differences were reviewed in a consensus meeting using a nominal group technique without a hierarchy. The shape of the femoral footprint was described as ribbon-like (or flattened), oval/elliptical, round/circular, semicircular, small-semicircular or undetermined in accordance with the classifications previously proposed [ 3 , 18 , 19 , 26 , 34 , 35 , 37 ].…”

“…The shape of the femoral footprint was described as ribbon-like (or flattened) [ 37 ], oval/elliptical, [ 3 , 18 , 19 , 21 , 26 , 34 , 35 , 38 ] round/circular [ 10 , 12 ], or semicircular [ 7 ]. In this study, a significant difference between the morphology was seen between cadavers of those younger and older than 50 years.…”

“…The dissection technique was standardized and performed in the same way by all the team members to ensure consistency, and was based on our own experience and the dissection protocols reported in previous studies [ 3 , 16 , 19 , 26 , 34 , 37 , 39 , 40 ]. The team consisted of a knee surgeon (FVC), an anatomist (REEO), and a senior orthopedic surgery and traumatology resident (JRPM).…”

“…ACL reconstruction was conventionally performed with a single-round femoral tunnel. However, some anatomical studies have revealed that the ACL femoral footprint is relatively elliptical in shape, not round [ 19 ]. Therefore, the use of bi-fascicular techniques or the realization of rectangular or oval tunnels have been proposed to try to imitate the native anatomy of the femoral insertion of the ACL in a more precise way.…”

Size Comparison of the Cadaveric Anterior Cruciate Ligament Midsubstance Cross-Sectional Area and the Cross-Sectional Area of Semitendinosus Double-Bundle Anterior Cruciate Ligament Reconstruction Autografts in Surgery

“…In recent ACL studies, the topics of focus have been mainly femoral and tibial ACL footprint anatomy, ACL biomechanical testing according to the reconstruction method, and graft selection. 5,6,13,15,[22][23][24][25][26][27][28][29][30][31] Many studies have reported that double-bundle reconstruction using hamstrings and rectangular BTB grafts 1,6,7,11,15 can reproduce native ACL footprint anatomy. However, not many studies have attempted to reveal the morphological correlation between the midsubstance of the reconstructed autograft and the native midsubstance ACL.…”