title: Effect of platelet-rich plasma and porcine dermal collagen graft augmentation for rotator cuff healing in a rabbit model.
abstract: BACKGROUND
  The rate of healing failure after surgical repair of chronic rotator cuff tears is considerably high.
  
  
  OBJECTIVE
  To verify the effect of platelet-rich plasma (PRP) with and without porcine dermal collagen graft augmentation on tendon-to-bone healing, using the rabbit supraspinatus tendon.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  A total of 80 rabbits were randomly allocated into 4 groups (20 rabbits per group: 12 for histological and 8 for mechanical testing): repair (R), repair + patch augmentation (RPa), repair + PRP (RPr), and repair + patch + PRP (RPaPr). The right shoulder was used for experimental interventions, and the left served as a control. Six weeks after the detachment of the supraspinatus, the torn tendon was repaired in a transosseous manner, simulating double-row repair in all groups. Platelet-rich plasma was prepared and applied onto the repair site in the RPr and RPaPr groups, and the patch was used to augment the repair in the RPa and RPaPr groups. The mechanical tensile strength test was performed at 8 weeks after repair and the histological evaluation at 4 and 8 weeks.
  
  
  RESULTS
  At 4 weeks, the collagen fibers were poorly organized, and fiber continuity was not established in all groups. However, vascularity and cellularity were higher with granulation tissue formation in the PRP-treated groups (RPr and RPaPr) than the nontreated groups (R and RPa). At 8 weeks, tendon-to-bone integration was much improved with more collagen fibers, and longitudinally oriented collagen fibers were visible in all groups. The PRP-treated groups showed better collagen fiber continuity and orientation than the nontreated groups; however, no distinctive difference was found between the patch-augmented groups (RPa and RPaPr) and nonaugmented groups (R and RPr). The mean load-to-failure results were 61.57 ± 29.99 N, 76.84 ± 16.08 N, 105.35 ± 33.82 N, and 117.93 ± 12.60 N for the R, RPa, RPr, and RPaPr groups, respectively, and they were significantly different between the R and RPr (P = .018), R and RPaPr (P = .002), and RPa and RPaPr (P = .029) groups.
  
  
  CONCLUSIONS
  This animal study showed the enhancement of tendon-to-bone healing after local administration of autologous PRP assessed by histological and biomechanical testing in a rabbit model of chronic rotator cuff tears. However, there was little additive effect of the patch graft.
  
  
  CONCLUSIONS
  The use of PRP might be a biological supplement to increase the rotator cuff healing rate, which still remains low even after successful cuff repair, but this result should be interpreted with caution regarding clinical applications.
authors.affiliation: Joo Han Oh, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 beon-gil, Bundang-gu, Seongnam 463-707, Korea. ohjh1@snu.ac.kr / ojhysy@snubh.org / ojhysy@gmail.com.
authors.forename: Seok Won
authors.initials: SW
authors.lastname: Chung
authors.forename: Byung Wook
authors.initials: BW
authors.lastname: Song
authors.forename: Yeun Ho
authors.initials: YH
authors.lastname: Kim
authors.forename: Kyoung Un
authors.initials: KU
authors.lastname: Park
authors.forename: Joo Han
authors.initials: JH
authors.lastname: Oh
mesh_terms: D000818:Animals; D003094:Collagen / Q000494:pharmacology*; D003238:Connective Tissue / Q000637:transplantation; D004195:Disease Models, Animal; D008297:Male; D053657:Platelet-Rich Plasma; D011817:Rabbits; D017006:Rotator Cuff / Q000187:drug effects / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012421:Rupture / Q000601:surgery / Q000628:therapy; D012782:Shoulder / Q000601:surgery*; D000070599:Shoulder Injuries; D012867:Skin / Q000737:chemistry; D013552:Swine; D013708:Tendon Injuries / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*; D013710:Tendons / Q000187:drug effects* / Q000473:pathology; D013718:Tensile Strength; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D003094:Collagen
keywords: growth factors/healing enhancement; platelet-rich plasma; porcine dermal collagen graft; rabbit model; rotator cuff; shoulder