title: Supraspinatus tendon organizational and mechanical properties in a chronic rotator cuff tear animal model.
abstract: Rotator cuff tears of the shoulder are a common cause of pain and disability. The successful repair of rotator cuff tendon tears depends on the time from onset of injury to the time of surgical repair. However, the effect of time from injury to repair remains poorly understood. A rat model was used to investigate the supraspinatus tendon organizational and mechanical property changes that occur with time post-injury to understand the natural injury response in the absence of repair. It was hypothesized that increased time post-injury would result in increased detrimental changes to tendon organizational and mechanical properties. Tendons were detached at the insertion on the humerus without repair and the quantitative organizational and mechanical properties were analyzed at 1, 2, 4, 8, and 16 weeks post-detachment. Tendon detachment resulted in a dramatic decrease in mechanical properties initially followed by a progressive increase with time. The quantitative collagen fiber orientation results provided corroborating support to the mechanical property data. Based on similarities in histology and mechanical properties to rotator cuff tears in humans, the animal model presented here is promising for future investigations of the tendon's natural injury response in the absence of repair.
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 36th and Hamilton Walk, Philadelphia, PA 19104-6081, USA.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Gimbel
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Van Kleunen
authors.forename: Samir
authors.initials: S
authors.lastname: Mehta
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Perry
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Williams
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000379:methods; D002908:Chronic Disease; D003094:Collagen / Q000378:metabolism / Q000648:ultrastructure*; D004195:Disease Models, Animal; D004548:Elasticity; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000502:physiology; D017006:Rotator Cuff / Q000473:pathology* / Q000503:physiopathology*; D000070636:Rotator Cuff Injuries; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000503:physiopathology; D013708:Tendon Injuries / Q000473:pathology* / Q000503:physiopathology*; D013710:Tendons / Q000473:pathology / Q000503:physiopathology; D014783:Viscosity; D014945:Wound Healing / Q000502:physiology*
chemical_list: D003094:Collagen