title: A Canine Non-Weight-Bearing Model with Radial Neurectomy for Rotator Cuff Repair.
abstract: BACKGROUND
  The major concern of using a large animal model to study rotator cuff repair is the high rate of repair retears. The purpose of this study was to test a non-weight-bearing (NWB) canine model for rotator cuff repair research.
  
  
  METHODS
  First, in the in vitro study, 18 shoulders were randomized to 3 groups. 1) Full-width transections repaired with modified Mason-Allen sutures using 3-0 polyglactin suture, 2) Group 1 repaired using number 2 (#2) polyester braid and long-chain polyethylene suture, and 3) Partial-width transections leaving the superior 2 mm infraspinatus tendon intact without repair. In the in vivo study of 6 dogs, the infraspinatus tendon was partially transected as the same as the in vitro group 3. A radial neurectomy was performed to prevent weight bearing. The operated limb was slung in a custom-made jacket for 6 weeks.
  
  
  RESULTS
  In the in vitro study, mean ultimate tensile load and stiffness in Group 2 were significantly higher than Group 1 and 3 (p<0.05). In the in vivo study, gross inspection and histology showed that the preserved superior 2-mm portion of the infraspinatus tendon remained intact with normal structure.
  
  
  CONCLUSIONS
  Based on the biomechanical and histological findings, this canine NWB model may be an appropriate and useful model for studies of rotator cuff repair.
authors.affiliation: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, 55905, United States of America; Trauma Center, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai, 200080, China.
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Ji
authors.affiliation: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, 55905, United States of America.
authors.forename: Nirong
authors.initials: N
authors.lastname: Bao
authors.affiliation: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, 55905, United States of America.
authors.forename: Kai-Nan
authors.initials: KN
authors.lastname: An
authors.affiliation: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, 55905, United States of America.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Amadio
authors.affiliation: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, 55905, United States of America.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Steinmann
authors.affiliation: Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, 55905, United States of America.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Zhao
mesh_terms: D000818:Animals; D001178:Arthroplasty / Q000379:methods*; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D004285:Dogs; D006801:Humans; D011826:Radial Nerve / Q000601:surgery*; D017006:Rotator Cuff / Q000294:innervation / Q000601:surgery*; D012783:Shoulder Dislocation / Q000601:surgery*; D013314:Stress, Mechanical; D013536:Suture Techniques; D013537:Sutures; D013710:Tendons / Q000294:innervation / Q000601:surgery*; D013718:Tensile Strength; D016474:Weight-Bearing; D014945:Wound Healing / Q000502:physiology