title: Effect of low-intensity pulsed ultrasound on fracture callus mineral density and flexural strength in rabbit tibial fresh fracture.
abstract: BACKGROUND
  Low-intensity ultrasound is a biophysical intervention on a fracture repair process. However, the effect of low-intensity ultrasound therapy on fracture healing is controversial. The aim of the present study was to evaluate the effect of low-intensity pulsed ultrasound (LIPUS) therapy on the fracture healing process, including mineral density and strength of callus using a rabbit model.
  
  
  METHODS
  A total of 30 rabbits underwent unilateral, transverse, and mid-tibia open osteotomies that were stabilized with external fixators. Then, the animals were divided into two study groups composed of 15 rabbits each: the case group (US), which were exposed to low-intensity pulsed ultrasound with 30 mW/cm(2) intensity and 1.5 MHz sine waves; and the control group (C), which underwent sham ultrasound treatment. Callus development and mineral density were evaluated using multidetector computed tomography at 2, 5, and 8 weeks, after which the animals were killed. Three-point bending tests of both healed and intact bones were assessed and compared.
  
  
  RESULTS
  The results demonstrated that the callus mineral density in the US group was higher than in the C group (1202.20 +/- 81.30 vs. 940.66 +/- 151.58 HU; P = 0.001) at the end of the 8th week. The mean recorded three-point bending test score of healed bones in the US group was not significantly different from that of the C group (359.35 +/- 173.39 vs. 311.02 +/- 80.58 N; P = 0.114).
  
  
  CONCLUSIONS
  The present study showed that low-intensity pulsed ultrasound enhanced callus mineral density with an insignificant increase in the strength of the fractured bone.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Tabriz University (Medical Sciences), Tabriz, Iran.
authors.forename: Kazem
authors.initials: K
authors.lastname: Shakouri
authors.forename: Bina
authors.initials: B
authors.lastname: Eftekharsadat
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Oskuie
authors.forename: Jafar
authors.initials: J
authors.lastname: Soleimanpour
authors.forename: Mohammad Kazem
authors.initials: MK
authors.lastname: Tarzamni
authors.forename: Yagoub
authors.initials: Y
authors.lastname: Salekzamani
authors.forename: Yousef
authors.initials: Y
authors.lastname: Hoshyar
authors.forename: Nariman
authors.initials: N
authors.lastname: Nezami
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density; D002146:Bony Callus / Q000503:physiopathology*; D005260:Female; D017102:Fracture Healing / Q000502:physiology; D011817:Rabbits; D013978:Tibial Fractures / Q000503:physiopathology / Q000601:surgery*; D014464:Ultrasonic Therapy