title: Potential Role of Local Estrogen in Enhancement of Fracture Healing: Preclinical Study in Rabbits.
abstract: BACKGROUND
  Effects of estrogen on bone metabolism and its protective role on prevention of osteoporosis are well documented. However, the efficacy of estrogen treatment on bone healing is not well investigated. The drug can be delivered both systemically or locally to the bone with differences in concentrations and side effects. The aim of this study was to investigate the effect of local and systemic administration of estrogen on the fracture healing process.
  
  
  METHODS
  Standardized tibial fractures with 4 millimeter gaps were created in twenty four adult male Dutch rabbits. Fractures were fixed using intramedullary wires and long leg casts. Rabbits were randomly divided into three groups. Group A was treated with twice a week administration of long acting systemic estrogen; group B was treated with a similar regimen given locally at the fracture gap; and group C received sham normal saline injections (control). Fracture healing was assessed at six weeks post fracture by gross examination, radiographic and histomorphometric analysis.
  
  
  RESULTS
  Group B had significantly higher gross stability, radiographic union and gap reduction than the two other groups. Histomorphometric analysis showed higher cartilaginous proportion of periosteal callus area in the control group.
  
  
  CONCLUSIONS
  Our results showed that estrogen may enhance fracture healing of long bone in rabbits. Furthermore, local estrogen treatment might have better effect than systemic treatment.
authors.affiliation: Bone and Joint Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Tahami
authors.affiliation: Bone and Joint Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Behrooz
authors.initials: B
authors.lastname: Haddad
authors.affiliation: Bone and Joint Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Armin
authors.initials: A
authors.lastname: Abtahian
authors.affiliation: Bone and Joint Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Hashemi
authors.affiliation: Bone and Joint Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Aminian
authors.affiliation: Bone and Joint Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Sujith
authors.initials: S
authors.lastname: Konan
keywords: Fracture healing; Local estrogen; Preclinical study; Rabbit