Estudo das terminacoes nervosas e mecanorreceptores do ligamento anterolateral do joelho

Abstract

The Anterolateral Ligament (ALL) of the knee is considered a secondary stabilizer of the Anterior Cruciate Ligament (ACL), mainly affecting the rotational stability in ACL failure. However, the role of LAL in dynamic stability and knee proprioception has not been well elucidated. Thus, aiming to understand this role, the aim of the present study is to describe the morphology and distribution of the ALL mechanoreceptors and nerve ending. Twenty ALL were obtained from fresh frozen cadavers. The ligaments were measured, weighed and cut. The 10μm sections were prepared in hematoxylin-eosin (HE) stained slides in order to analyze tissue integrity, and the 50μm sections were subjected to immunofluorescence with the protein gene product (PGP) 9.5 as primary antibody and Alexa Fluor 488 as secondary antibody, followed by microscopic analysis (Zeiss® LMS 710). The ALL was identified in 100% of the dissections, exhibiting a mean length of 4.0 ± 0.4 cm, a mean width of 5.5 ± 0.8 mm and a mean weight of 0.9 ± 0.2 g. The histological sections in HE showed dense wellorganized collagen and the presence of vascular tissue. All the specimens analyzed contained type I (Ruffini-like) mechanoreceptors and type IV (free nerve endings), varying from parallel to intertwined fibers. Unclassified nerve endings with different irregular shapes were also found. The neural elements occupied 0.6 ± 0.3% of the ligament area and most were observed near the origin of ALL insertions. Thus, it was concluded that ALL is a distinct ligament structure in the anterolateral aspect of the knee and exhibits a peripheral nerve structure, primarily type I and IV mechanoreceptors. These findings suggest that the ALL is important for the proprioception and anterolateral stabilization of the knee. Keywords: Ligament. Knee. Mechanoreceptors. Nerve endings. Fluorescent Antibody Technique.