Structural characterization of the anterolateral capsule of the knee ő a gross anatomic, histological, and magnetic resonance imaging study of the anterolateral ligament (914.6)

Abstract

For over 140 years, a structure located on the lateral side of the knee has been recognized but poorly understood by surgeons. Most recently termed the Anterolateral Ligament (ALL), it has been described to consistently originate on the lateral femoral condyle and insert onto the tibia posterior to Gerdy’s tubercle. This study aims to characterize the anatomical properties of the ALL utilizing magnetic resonance imaging, cadaveric dissection, and histological/immunohistochemical sectioning of fresh‐frozen human cadaveric knees. Preliminary results show that in each of the 7 cadaveric specimens undergoing 3T MRI analysis, the ALL can be identified as a distinct, densely arranged structure. The ALL was then clearly visualized in all 9 cadaveric dissections, showing variable origin on the lateral femoral condyle and consistent insertion on the tibia. H&E histological sectioning of 2 cadaveric specimens also indicates that the ALL is ligamentous in nature, revealing a dense, regular network of collagenous tissue. In 1 specimen, immunohistochemistry specific to neurofilament proteins found in axons show peripheral nervous innervation of the ALL, indicating ligamentous tissue. These results show that the ALL can be confidently identified in a multitude of different modalities, providing clear evidence that the ALL is a distinct ligament of the lateral knee.