title: The innervation of the human acetabular labrum and hip joint: an anatomic study.
abstract: BACKGROUND
  The aim of the current study was to evaluate the innervation of the acetabular labrum in the various zones and to understand its potential role in nociception and proprioception in hips with labral pathology.
  
  
  METHODS
  A total of twenty hip labrums were tagged and excised intraoperatively from patients undergoing a total hip replacement. After preparation, the specimens were cut to a thickness of 10 μm and divided into four quadrants (zones) using a clock face pattern. Neurosensory structure distribution was then evaluated using Hematoxylin and Eosin (H and E), and immunoreactivity to S-100.
  
  
  RESULTS
  All specimens had abundant free nerve endings (FNEs). These were seen predominantly superficially and on the chondral side of the labrum. In addition, predominantly three different types of nerve end organs (NEOs) were identified in all twenty specimens. FNEs and NEOs were more frequently seen in the antero-superior and postero-superior zones. Four specimens had abundant vascularity and disorganised architecture of FNEs in the deeper zones of the antero-superior quadrant suggestive of a healed tear. Myofibroblasts were present in abundance in all the labral specimens and were distributed uniformly throughout all labral zones and depth.
  
  
  CONCLUSIONS
  The current study shows that the human acetabular labrum has abundant FNEs and NEOs. These are more abundant in the antero-superior and postero-superior zones. The labrum, by virtue of its neural innervation, can potentially mediate pain as well as proprioception of the hip joint, and be involved in neurosecretion that can influence connective tissue repair.
authors: Abdullah
authors: A
authors: Alzaharani
authors: Kamal
authors: K
authors: Bali
authors: Ravi
authors: R
authors: Gudena
authors: Pamela
authors: P
authors: Railton
authors: Dragana
authors: D
authors: Ponjevic
authors: John R
authors: JR
authors: Matyas
authors: Orthopedic Trauma & Lower Extremity Reconstruction, 3134 Hospital Drive N,W, Calgary, Alberta T2N 5A1, Canada. jnpowellemail@yahoo.ca.
authors: James N
authors: JN
authors: Powell
mesh_terms: D000077:Acetabulum / Q000294:innervation* / Q000601:surgery; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D015415:Biomarkers / Q000032:analysis; D006621:Hip Joint / Q000294:innervation* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009411:Nerve Endings / Q000737:chemistry / Q000473:pathology*; D059225:Nociception; D015207:Osteoarthritis, Hip / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D011434:Proprioception; D009418:S100 Proteins / Q000032:analysis
chemical_list: D015415:Biomarkers; D009418:S100 Proteins