Cortical Bony Thickening of the Lateral Intercondylar Wall: The Functional Attachment of the Anterior Cruciate Ligament

Abstract

Background: The anatomy of the anterior cruciate ligament (ACL) has become the subject of much debate. There has been extensive study into attachment points of the native ligament, especially regarding the femoral attachment. Some of these studies have suggested that fibers in the ACL are of differing functional importance. Fibers with higher functional importance would be expected to exert larger mechanical stress on the bone. According to Wolff’s law, cortical thickening would be expected in these areas. Purpose: To examine cortical thickening in the region of the ACL footprint (ie, the functional footprint of the ACL). Study Design: Descriptive laboratory study. Methods: Using micro–computed tomography with resolutions ranging from 71 to 91 μm, the cortical thickness of the lateral wall of the intercondylar notch in 17 cadaveric knees was examined, along with surface topography. After image processing, the relationship between the cortical thickening and surface topology was visually compared. Results: A pattern of cortical thickening consistent with the functional footprint of the ACL was found. On average, this area was 3 times thicker than the surrounding bone and significantly thicker than the remaining lateral wall ( P < .0001). This thickening was roughly elliptical in shape (with a mean centroid at 23.5 h:31 t on a Bernard and Hertel grid) and had areas higher on the wall where greater thickness was present. The relationship to previously reported osseous landmarks was variable, although the patterns were broadly consistent with those reported in previous studies describing direct and indirect fibers of the ACL. Conclusion: The findings of this study are consistent with those of recent studies describing fibers in the ACL of differing functional importance. The area in which the thickening was found has been defined and is likely to represent the functional footprint of the ACL. Clinical Relevance: This information is of value to surgeons when determining the optimal place to position the femoral attachment site of the reconstructed ACL.

Reliability of Anatomic Bony Landmark Localization of the ACL Femoral Footprint Using 3D MRI

“…Generally, spatial resolution of MRI is lower than that of CT, which may be better suited to delineating the fine bony detail of the ridges. Of note, a recent study by Norman et al 29 utilized micro-CT for the analysis of the cortical thickening underlying the ACL footprint. Such a technique may allow for greater precision in characterizing the footprint surface area.…”

Anatomical relationship between the morphology of the styloid process of the ulna and the attachment of the radioulnar ligaments

“…These findings were validated by the fact that cortical bone thickening was limited in the dorsoradial part of the middle of the styloid process. As previously described, these bony morphological features, particularly cortical bone thickening, could correspond to the high tensile stress from the dense connective tissues (Tamaki et al ., 2014; Nozaki et al ., 2015; Norman et al ., 2017; Sato et al ., 2018).…”

“…Bone is highly adaptive when undergoing mechanical stress loads (Wolff, 1892). Previous reports have described that high tensile stresses via dense connective tissues, such as the tendon, ligament, and aponeurosis, affect the morphology and cortical bone thickness of the attachment (Tamaki et al, 2014;Nozaki et al, 2015;Norman et al, 2017;Sato et al, 2018). The distal ulna is known to be shaped by the cartilage surface, fovea, sulcus of the extensor carpi ulnaris, and styloid process.…”

Odnos lateralnog interkondilarnog grebena i hvatišta prednjeg križnog ligamenta

“…Na taj način smanjuje se rizik od nastanka avulzijskih fraktura 23,24 . Da je LIR koštani greben koji anatomskom strukturom odgovara gore navedenoj definiciji pokazali su Norman i suradnici koji su analizirali kost u području LIR-a i zaključili da je koštano područje koje odgovara LIR-u deblje i do 3 puta u odnosu na koštani dio preostalog dijela femoralnog hvatišta ACL-a 4 . Ovo koštano zadebljanje podudara se i s histološkim nalazom Sasakija i sur.…”