title: Effect of Postoperative Passive Motion on Rotator Cuff Reconstruction With Acellular Dermal Matrix Grafts in a Rat Model.
abstract: BACKGROUND
  Although postoperative rehabilitation is critical for rotator cuff tendon-to-bone healing and shoulder function recovery, no standardized protocol has been established.
  
  
  OBJECTIVE
  Postoperative immediate passive motion is detrimental to tendon-to-bone remodeling and tendon maturation after rotator cuff acellular dermal matrix (ADM) grafting, although postoperative delayed passive motion does no harm.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Male Sprague-Dawley rats underwent rotator cuff reconstruction with ADM grafts. Their shoulders were immobilized for 2 weeks thereafter. The rats were assigned to 3 different rehabilitation protocols: (1) immobilization without passive motion (nonpassive motion [N-PM], controls), (2) immobilization with immediate passive motion (I-PM), and (3) immobilization with delayed passive motion (D-PM). Specimens obtained 2, 6, and 12 weeks postoperatively were analyzed histologically, and semiquantitative histomorphological measurements of collagen organization, vascularity, and cellularity were obtained; the area of interest was divided into 2 zones, the midsubstance of the graft and the graft-bone interface. Another set of samples taken at 12 weeks was subjected to biomechanical analysis.
  
  
  RESULTS
  At 2 weeks, there was no significant difference among the groups in terms of semiquantitative histomorphological measurements of collagen organization, vascularity, and cellularity. At 6 weeks, collagen organization at the insertion site was significantly poorer in I-PM than in N-PM and D-PM rats (P = .0095). At 12 weeks, collagen organization at the insertion site and midsubstance of ADM grafts was also significantly poorer in I-PM rats (P = .0125 and P = .0018, respectively), and ultimate load-to-failure was lower in this group (P = .0043).
  
  
  CONCLUSIONS
  While postoperative immediate passive motion was detrimental to remodeled tendon-to-bone healing and to the tendon maturation of ADM grafts placed in the rotator cuff tendon defects, delayed passive motion did no harm.
  
  
  CONCLUSIONS
  For patients with 6-week immobilization after rotator cuff reconstruction, we recommend that early passive motion be started no sooner than 3 weeks after surgery. Immediate early passive motion should be avoided.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Uezono
authors.affiliation: Department of Advanced Joint Reconstructive Surgery, Kumamoto University Hospital, Kumamoto University, Kumamoto, Japan ide@kumamoto-u.ac.jp.
authors.forename: Junji
authors.initials: J
authors.lastname: Ide
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Tokunaga
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Arimura
authors.affiliation: Department of Mechanical System Engineering, Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Sakamoto
authors.affiliation: Department of Mechanical System Engineering, Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Nakanishi
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mizuta
mesh_terms: D062088:Acellular Dermis; D000818:Animals; D003094:Collagen / Q000502:physiology; D006801:Humans; D008297:Male; D023421:Models, Animal; D015915:Motion Therapy, Continuous Passive / Q000009:adverse effects; D011182:Postoperative Care / Q000379:methods; D016059:Range of Motion, Articular; D017207:Rats, Sprague-Dawley; D017006:Rotator Cuff / Q000502:physiology / Q000601:surgery*; D016038:Skin Transplantation; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects
chemical_list: D003094:Collagen
keywords: acellular dermal matrix graft; animal model; postoperative passive motion; rotator cuff reconstruction