title: Different effects of mechanical vibration on bone ingrowth into porous hydroxyapatite and fracture healing in a rabbit model.
abstract: The effects of mechanical vibration on bone ingrowth into porous hydroxyapatite implants and fracture healing were examined radiographically, histomorphometrically, and biomechanically in a rabbit model. Fifty-three female NZW rabbits were used in this study. These rabbits were divided into four separate studies to assess the effects of 20 and 60 min of vibration/day in both implant and osteotomy models as compared with the respective non-vibrated controls. For the implant model, coral hydroxyapatite goniopora rods were implanted bilaterally into tibiae and for the osteotomy model, bilateral fibulae were osteotomized. A resonant frequency of 25 Hz mechanical vibration was used. After periods of 2, 3, 4, and 6 weeks of vibration, the rabbits were killed and examined. For the implant model, there was no significant difference between control, 20, or 60 min of vibration/day with respect to the rate or amount of new bone ingrowth. For the fracture model, 60 min of vibration/day produced a significantly larger callus as compared with the non-vibrated controls (p less than 0.05), whereas 20 min of vibration/day did not. Although biomechanical testing demonstrated a general trend for increased strength in the vibrated animals, it failed to reach significance. These results suggest that the mechanical vibration used in the present study had a beneficial effect on callus volume, possibly due to the stimulation of secondary bone healing processes, but does not appear to promote bone ingrowth into a porous hydroxyapatite implant.
authors.affiliation: Division of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas 75235-9031.
authors.forename: Y
authors.initials: Y
authors.lastname: Usui
authors.forename: J E
authors.initials: JE
authors.lastname: Zerwekh
authors.forename: H
authors.initials: H
authors.lastname: Vanharanta
authors.forename: R B
authors.initials: RB
authors.lastname: Ashman
authors.forename: V
authors.initials: V
authors.lastname: Mooney
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001858:Bone Nails; D002146:Bony Callus / Q000000981:diagnostic imaging; D017886:Durapatite; D005260:Female; D050723:Fractures, Bone / Q000503:physiopathology*; D006614:Hindlimb; D006882:Hydroxyapatites; D008855:Microscopy, Electron, Scanning; D010012:Osteogenesis; D010027:Osteotomy; D010539:Permeability; D011817:Rabbits; D011859:Radiography; D014732:Vibration; D014945:Wound Healing
chemical_list: D006882:Hydroxyapatites; D017886:Durapatite