title: Low-intensity ultrasound application in distal radius metaphyseal bone defects of dogs.
abstract: We assessed the repair of transverse, 3-mm wide bone gaps created at the distal radius in 28 dogs that were randomly divided into two 14-animal groups; one was the control group and the other received a daily, 20-min application of low-intensity pulsed ultrasound for 100 days. Sequential radiographs, histomorphometrics, bone fluorescent histology and bone vascularity assessments found that all animals from both groups obtained a stage of hypertrophic-type nonunion with fibrocartilage tissue formation throughout the region of osteotomy. However, treated animals exhibited areas of endochondral ossification within the fibrocartilage region. There was no difference in type of vascularity or the newly formed bone process obtained by tetracycline labeling. Application of low-intensity ultrasound was not capable of significantly changing the reparative process and it may not be sufficiently powerful to overcome a combination of local deleterious effects on bone healing, created by gapping, excessive motion and periosteal resection.
authors.affiliation: University of Sao Paulo School of Medicine, Ribeirao Preto, SP, Brazil. jbvolpon@fmrp.usp.br
authors.forename: Jose B
authors.initials: JB
authors.lastname: Volpon
authors.forename: Francisco C Dantas
authors.initials: FC
authors.lastname: Mota
authors.forename: Marcelo E
authors.initials: ME
authors.lastname: Beletti
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D006244:Hardness; D011884:Radius / Q000293:injuries*; D011897:Random Allocation; D018709:Statistics, Nonparametric; D014464:Ultrasonic Therapy / Q000379:methods*; D014945:Wound Healing / Q000502:physiology*