title: Photoencapsulation of bone morphogenetic protein-2 and periosteal progenitor cells improve tendon graft healing in a bone tunnel.
abstract: BACKGROUND
  Tissue-engineered solutions for promoting the tendon graft incorporation within the bone tunnel appear to be promising.
  
  
  OBJECTIVE
  To determine the feasibility that conjugation of hyaluronic acid-tethered bone morphogenetic protein-2 can be used to stimulate periosteal progenitor cells direct fibrocartilagenous attachment and new bone formation in an extra-articular tendon-bone healing model.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  A total of 42 mature New Zealand White rabbits were used. The long digitorum extensor tendon was transplanted into a bone tunnel of the proximal tibia. The tendon was pulled through a drill hole in the proximal tibia and attached to the medial aspect of the tibia. Photopolymerizable hydrogel based on poly (ethylene glycol) diacrylate with hyaluronic acid-tethered bone morphogenetic protein-2 was injected and photogelated in a bone tunnel. Histological and biomechanical examination of the tendon-bone interface was evaluated at postoperative weeks 3 and 6.
  
  
  RESULTS
  Histological analysis showed an interface fibrocartilage and new bone formed by photoencapsulation of bone morphogenetic protein-2 and periosteal progenitor cells at 6 weeks. Biomechanical testing revealed higher maximum pullout strength and stiffness in experimental groups with a statistically significant difference at 3 and 6 weeks after tendon transplantation.
  
  
  CONCLUSIONS
  The healing tendon-bone interface undergoes a gradual remodeling process; it appears that photoencapsulation of bone morphogenetic protein-2 and periosteal progenitor cells possesses a powerful inductive ability between the tendon and the bone to incorporate the healing in a rabbit model.
  
  
  CONCLUSIONS
  Novel technologies, such as those described in this study, including photopolymerization and tissue engineering, may provide minimally invasive therapeutic procedures via arthroscopy to enhance biological healing after reconstruction of the anterior cruciate ligament.
authors.affiliation: Department of Orthopaedic Surgery, College of Medicine, Chang Gung Memorial Hospital-Keelung, Chang Gung University, Keelung, Taiwan.
authors.forename: Chih-Hwa
authors.initials: CH
authors.lastname: Chen
authors.forename: Hsia-Wei
authors.initials: HW
authors.lastname: Liu
authors.forename: Ching-Lin
authors.initials: CL
authors.lastname: Tsai
authors.forename: Chung-Ming
authors.initials: CM
authors.lastname: Yu
authors.forename: I-Hsuan
authors.initials: IH
authors.lastname: Lin
authors.forename: Ging-Ho
authors.initials: GH
authors.lastname: Hsiue
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D016723:Bone Remodeling / Q000187:drug effects*; D002470:Cell Survival; D006820:Hyaluronic Acid / Q000008:administration & dosage; D020100:Hydrogels / Q000008:administration & dosage; D015552:Injections, Intralesional; D008856:Microscopy, Fluorescence; D010521:Periosteum / Q000166:cytology; D011092:Polyethylene Glycols / Q000008:administration & dosage; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D033581:Stem Cell Transplantation / Q000379:methods*; D013234:Stem Cells / Q000502:physiology / Q000528:radiation effects; D013708:Tendon Injuries / Q000473:pathology / Q000628:therapy*; D013710:Tendons / Q000473:pathology / Q000637:transplantation*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage*; D014466:Ultraviolet Rays
chemical_list: D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D020100:Hydrogels; D016212:Transforming Growth Factor beta; C437167:poly(ethylene glycol)diacrylate; D011092:Polyethylene Glycols; D006820:Hyaluronic Acid