Characterisation and Classification of the Neural Anatomy in the Human Hip Joint

Abstract

Hip arthroscopy remains a useful surgical intervention for labral injuries. The literature has predominantly focused on structural and vascular considerations of the hip joint, with few studies examining the neurohistology of the surrounding periarticular tissues. We mapped and identified the periarticular neural anatomy, to identify the presence of sensory nerve fibres and mechanoreceptors within the hip joint. Eight human cadaveric hips were dissected into a total of ten specimens per hip. Histological staining was used to identify neural structures taken from the superolateral, anterior, inferior, and posterior positions of the hip joint. The frozen sections were analyzed by light microscopy to calculate relative concentrations of mean neural fibres per high power field (mnf/hpf). Neural end organs were found in the hip capsule, acetabular labrum, ligamentum teres and transverse acetabular ligament. The highest levels of mechanoreceptors were found in the superolateral aspect of the hip capsule (9.6 mnf/hpf). The labrum showed highest levels of sensory fibres (3.4 mnf/hpf) and mechanoreceptors (4.3mnf/hpf) within the anterior zone. Sensory fibres and mechanoreceptors densely populate the acetabular labrum, capsule and transverse acetabular ligament. The anterior zone of the labrum contained the highest relative concentration of sensory fibres, specifically Ruffini corpuscles.

Normal microscopic architecture of acetabular labrum of hip joint: a qualitative original study with clinical aspects

“…However, their results are doubtful as mentioned. Our anatomic division is similar with the studies that our findings are in agreement with 2,3 . It was thus reported that anterior labrum contains the highest FNEs and NEOs concentration.…”

“…In our study, FNEs and NEOs were basically detected in ventral (anterior) part of the labrum (zones 1 and 2). This finding is in full agreement with these of two studies 2,3 , in partial agreement with another study 1 , and in full disagreement with the last study 4 Table I. General characteristics of reported studies regarding normal histologic architecture of acetabular labrum.…”

“…However, these topographic conclusions remain doubtful due to the fact that results were based on histological investigation of only one acetabular labrum. Gerhardt et al 2 conducted subsequently a histological investigation of acetabular labrum on 8 human cadaveric hips with mean age 76.5 years, reporting the presence of FNEs and Pacini and Ruffini corpuscles. Ruffini corpuscles were detected to a greater extent in comparison with Paccini.…”

“…NEOs constitute fundamental microscopic structures detected in capsules, muscles and tendons. Presence of NEOs and FNEs in normal acetabular labrum has been described four times [1][2][3][4] . Two of these studies 1, 2 were cadaveric, utilizing cadaveric specimens for acetabular labrum histological evaluation, while, in one study 3 labral specimens of patients with coxarthrosis subjected to total hip arthroplasty were utilized.…”

“…NEOs are consequently functionally related with proprioception. Presence of FNEs and NEOs in acetabular labrum of normal hip joint has been described three times [1][2][3] , being additionally specially analyzed within a general review on neural anatomy of hip joint 4 . Results present a relative diversity among the studies.…”