title: Biomechanical evaluation of a novel suturing scheme for grafting load-bearing collagen scaffolds for rotator cuff repair.
abstract: BACKGROUND
  Currently, there are no well-established suture protocols to attach fully load-bearing scaffolds which span tendon defects between bone and muscle for repair of critical sized tendon tears. Methods to attach load-bearing tissue repair scaffolds could enable functional repair of tendon injuries.
  
  
  METHODS
  Sixteen rabbit shoulders were dissected (New Zealand white rabbits, 1yr. old, female) to isolate the humeral-infraspinatus muscle complex. A unique suture technique was developed to allow for a 5mm segmental defect in infraspinatus tendon to be replaced with a mechanically strong bioscaffold woven from pure collagen threads. The suturing pattern resulted in a fully load-bearing scaffold. The tensile stiffness and strength of scaffold repair were compared with intact infraspinatus and regular direct repair.
  
  
  RESULTS
  The failure load and displacement at failure of the scaffold repair group were 59.9N (standard deviation, SD=10.7) and 10.3mm (SD=2.9), respectively and matched those obtained by direct repair group which were 57.5N (SD=15.3) and 8.6mm (SD=1.5), (p>0.05). Failure load, displacement at failure and stiffness of both of the repair groups were half of the intact infraspinatus shoulder group.
  
  
  CONCLUSIONS
  With the developed suture technique, scaffold repair showed similar failure load, displacement at failure and stiffness to the direct repair. This novel suturing pattern and the mechanical robustness of the scaffold at time zero indicates that the proposed model is mechanically viable for future in vivo studies which has a higher potential to translate into clinical uses.
authors.affiliation: Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Anowarul
authors.initials: A
authors.lastname: Islam
authors.affiliation: The Warren Alpert Medical School of Brown University, Providence, RI 02912, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bohl
authors.affiliation: Department of Orthopaedics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Tsai
authors.affiliation: Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Mousa
authors.initials: M
authors.lastname: Younesi
authors.affiliation: Department of Orthopaedics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Gillespie
authors.affiliation: Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Orthopaedics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA. Electronic address: oxa@case.edu.
authors.forename: Ozan
authors.initials: O
authors.lastname: Akkus
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003094:Collagen / Q000627:therapeutic use; D004195:Disease Models, Animal; D005260:Female; D011817:Rabbits; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D013536:Suture Techniques; D013708:Tendon Injuries / Q000601:surgery; D054457:Tissue Scaffolds; D016474:Weight-Bearing / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology
chemical_list: D003094:Collagen
keywords: Collagen suture technique; Infraspinatus tendon; Mechanical properties; Scaffold; Segmental rotator cuff defect; Strength