title: Rotator cuff repair using an acellular dermal matrix graft: an in vivo study in a canine model.
abstract: OBJECTIVE
  Large rotator cuff tears present a challenge to orthopaedic surgeons. Because tissue may be insufficient or of inadequate quality to undergo repair, a variety of materials have been used as adjuncts. Human dermal tissue may be processed to render it acellular, and thus less immunogenic, but with the extracellular matrix left intact, creating a collagen scaffold with favorable characteristics. Because of these traits, use in rotator cuff repair was proposed.
  
  
  METHODS
  A canine model for a full-thickness infraspinatus tendon tear was used. Tendon was excised from the bony interface to the myotendinous junction, and a human acellular dermal matrix graft (experimental) or the autologous excised tendon (control) was used to bridge the defect. Animals were sacrificed, and shoulders were evaluated histologically and biomechanically.
  
  
  RESULTS
  At time 0, strength of control and experimental repairs was similar. At 6 weeks, the strength of the experimental repair was half that of the control side. Strength of control specimens remained the same at 6 and 12 weeks, but by 12 weeks, the strength of the experimental repair was equal to that of the control. Histologically, cells infiltrated the control and experimental specimens by 6 weeks; chronic inflammation was consistent with surgery and repair. At 6 months, control and experimental specimens mimicked normal tendon structure grossly and histologically.
  
  
  CONCLUSIONS
  Use of human acellular dermal matrix as a patch is a viable option in this model of large rotator cuff defects. Within 6 weeks, histologic evidence of native cell infiltration and neotendon development was observed. Within 12 weeks, the strength of the dermal matrix graft repair was equivalent to that of autologous tendon. At 6 months, control and graft specimens mimicked normal tendon structure grossly and histologically.
  
  
  CONCLUSIONS
  This study provides in vivo animal data to support the use of this acellular dermal matrix graft for repair of full-thickness rotator cuff defects. Additional studies are indicated to determine the role of this material in the treatment of humans with rotator cuff tears.
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Julie E
authors.initials: JE
authors.lastname: Adams
authors.forename: Mark E
authors.initials: ME
authors.lastname: Zobitz
authors.forename: John S
authors.initials: JS
authors.lastname: Reach
authors.forename: Kai-Nan
authors.initials: KN
authors.lastname: An
authors.forename: Scott P
authors.initials: SP
authors.lastname: Steinmann
mesh_terms: D000818:Animals; D002474:Cell-Free System; D004285:Dogs; D006801:Humans; D022125:Lacerations / Q000503:physiopathology / Q000601:surgery*; D017006:Rotator Cuff / Q000503:physiopathology; D000070636:Rotator Cuff Injuries; D016038:Skin Transplantation / Q000379:methods*; D013708:Tendon Injuries / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D013710:Tendons / Q000254:growth & development / Q000473:pathology / Q000601:surgery; D013997:Time Factors; D014183:Transplantation, Heterologous; D016896:Treatment Outcome