title: Tendon to bone healing: differences in biomechanical, structural, and compositional properties due to a range of activity levels.
abstract: Little knowledge exists about the healing process of the tendon to bone insertion, and hence little can be done to improve tissue healing. The goal of this study is to describe the healing of the supraspinatus tendon to its bony insertion under a variety of loading conditions. Tendons were surgically detached and repaired in rats. Rat shoulders were then immobilized, allowed cage activity, or exercised. Shoulders that were immobilized demonstrated superior structural (significantly higher collagen orientation), compositional (expression of extracellular matrix genes similar to the uninjured insertion), and quasilinear viscoelastic properties (A = 0.30 +/- 0.10 MPa vs. 0.16 +/- 0.08 MPa, B = 17.4 +/- 2.9 vs. 15.1 +/- 0.9, and tau 2 = 344 +/- 161 s vs. 233 +/- 40 s) compared to those that were exercised, contrary to expectations. With this knowledge of the healing response, treatment modalities for rotator cuff tears can be developed.
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, Philadelphia, PA 19104-6081, USA.
authors.forename: S
authors.initials: S
authors.lastname: Thomopoulos
authors.forename: G R
authors.initials: GR
authors.lastname: Williams
authors.forename: L J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000293:injuries / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002370:Casts, Surgical; D004548:Elasticity; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D007103:Immobilization; D051381:Rats; D017207:Rats, Sprague-Dawley; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D013708:Tendon Injuries / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology* / Q000628:therapy; D014783:Viscosity
chemical_list: D016326:Extracellular Matrix Proteins