title: Bone morphogenetic protein-7 accelerates fracture healing in osteoporotic rats.
abstract: BACKGROUND
  Osteoporosis is characterized by low bone mass, bone fragility and increased susceptibility to fracture. Fracture healing in osteoporosis is delayed and rates of implant failure are high with few biological treatment options available. This study aimed to determine whether a single dose of bone morphogenetic protein-7 (BMP-7) in a collagen/carboxy-methyl cellulose (CMC) composite enhanced fracture healing in an osteoporotic rat model.
  
  
  METHODS
  An open femoral midshaft osteotomy was performed in female rats 3 months post-ovarectomy. Rats were randomized to receive either BMP-7 composite (n = 30) or composite alone (n = 30) at the fracture site during surgery. Thereafter calluses were collected on days 12, 20 and 31. Callus cross-sectional area, bone mineral density, biomechanical stiffness and maximum torque, radiographic bony union and histological callus maturity were evaluated at each time point.
  
  
  RESULTS
  There were statistically significant increases in bone mineral density and callus cross-section area at all time points in the BMP-7 group as compared to controls and biomechanical readings showed stronger bones at day 31 in the BMP-7 group. Histological and radiographic evaluation indicated significant acceleration of bony union in the BMP-7 group as compared to controls.
  
  
  CONCLUSIONS
  This study demonstrated that BMP-7 accelerates fracture healing in an oestrogen-deficient environment in a rat femoral fracture healing model to scientific relevance level I. The use of BMP-7 composite could offer orthopedic surgeons an advantage over oestrogen therapy, enhancing osteoporotic fracture healing with a single, locally applied dose at the time of surgery, potentially overcoming delays in healing caused by the osteoporotic state.
authors.affiliation: Orthopaedic Research Institute; Department of Orthopaedic Surgery, St. George Hospital Clinical School, University of New South Wales, Kogarah, New South Wales, Australia ; Department of Orthopaedic Surgery, St. George Hospital Clinical School, University of New South Wales, Kogarah, New South Wales, Australia.
authors.forename: Ashish D
authors.initials: AD
authors.lastname: Diwan
authors.affiliation: Department of Orthopaedic Surgery, St. George Hospital Clinical School, University of New South Wales, Kogarah, New South Wales, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: Leong
authors.affiliation: Orthopaedic Research Institute; Department of Orthopaedic Surgery, St. George Hospital Clinical School, University of New South Wales, Kogarah, New South Wales, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Appleyard
authors.affiliation: Orthopaedic Research Institute; Department of Orthopaedic Surgery, St. George Hospital Clinical School, University of New South Wales, Kogarah, New South Wales, Australia.
authors.forename: Divya
authors.initials: D
authors.lastname: Bhargav
authors.affiliation: Orthopaedic Research Institute; Department of Orthopaedic Surgery, St. George Hospital Clinical School, University of New South Wales, Kogarah, New South Wales, Australia.
authors.forename: Zhi Ming
authors.initials: ZM
authors.lastname: Fang
authors.affiliation: Orthopaedic Research Institute; Department of Orthopaedic Surgery, St. George Hospital Clinical School, University of New South Wales, Kogarah, New South Wales, Australia.
authors.forename: Aiqun
authors.initials: A
authors.lastname: Wei
keywords: Bone morphogenetic protein-7; carboxy-methyl cellulose; oestrogen; osteoporotic fracture healing; rat femur