title: Histopathology of the supraspinatus tendon in rotator cuff tears.
abstract: BACKGROUND
  Causes of rotator cuff pathology are poorly understood.
  
  
  OBJECTIVE
  Macroscopically intact supraspinatus tendon may show profound light microscopy changes. These changes may be the pathogenic precursor to a subsequent rotator cuff tear.
  
  
  METHODS
  Comparative laboratory study.
  
  
  METHODS
  Tendon samples were harvested from 88 individuals (49 men, 39 women; mean age, 58.2 years) who had sustained a rotator cuff tear and underwent arthroscopic repair of the lesion, and from 5 male patients who died of cardiovascular events (mean age, 69.6 years). A full-thickness supraspinatus tendon biopsy specimen was harvested en bloc within the arthroscopically intact middle portion of the tendon between the lateral edge of the tendon tear and the muscle-tendon junction. Slides stained with hematoxylin and eosin were interpreted twice by the same observer using a semiquantitative grading scale assessing fiber structure and arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. Intraobserver reliability of the subscore readings was calculated.
  
  
  RESULTS
  The mean pathologic sum-score of ruptured tendons was significantly greater than the mean pathologic score of control tendons (15.66 +/- 1.82 vs 3.7 +/- 2.31, P = .001). Within each specific category of tendon abnormalities, the control and ruptured tendons were significantly different (chi(2) test); all variables were significantly different (Mann-Whitney U test <0.05; P = .001). The agreement between the 2 readings ranged from 0.56 to 0.86 (kappa statistics).
  
  
  CONCLUSIONS
  Nonruptured supraspinatus tendons, even at an advanced age, and ruptured supraspinatus tendons are clearly part of 2 distinct populations.
  
  
  CONCLUSIONS
  During cuff repair, it is not necessary to excessively freshen the torn tendon to bleeding tissue: the macroscopically intact supraspinatus tendon is degenerated as well, and the failed healing response is not limited to the ends of the torn tendon.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Campus Biomedico University, Rome, Italy.
authors.forename: Umile Giuseppe
authors.initials: UG
authors.lastname: Longo
authors.forename: Francesco
authors.initials: F
authors.lastname: Franceschi
authors.forename: Laura
authors.initials: L
authors.lastname: Ruzzini
authors.forename: Carla
authors.initials: C
authors.lastname: Rabitti
authors.forename: Sergio
authors.initials: S
authors.lastname: Morini
authors.forename: Nicola
authors.initials: N
authors.lastname: Maffulli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Denaro
mesh_terms: D000368:Aged; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D017006:Rotator Cuff / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D000070636:Rotator Cuff Injuries
chemical_list: D003094:Collagen