Combined Treatment of Alendronate and Low-Intensity Pulsed Ultrasound (LIPUS) Increases Bone Mineral Density at the Cancellous Bone Osteotomy Site in Aged Rats: A Preliminary Study.

Abstract

During fracture healing, alendronate encourages callus volume by inhibiting bone resorption, whereas low-intensity pulsed ultrasound (LIPUS) enhances bone regeneration by promoting an anabolic response. In the present study, 9-month-old Sprague-Dawley rats, with a unilateral proximal tibial osteotomy, were treated with alendronate (daily, 1 µg/kg) plus sham-LIPUS (n = 14), saline plus LIPUS (20 min/day) (n = 18), alendronate plus LIPUS (n = 16), or saline plus sham-LIPUS as a control (n = 13) for 4 weeks. The rats were then examined for changes in bone mineral density (BMD) during metaphyseal bone repair. The combined therapy significantly increased BMD at the osteotomy site at 4 weeks (p < 0.001) compared with the control, without affecting the contralateral, non-osteotomized tibia. Both alendronate and LIPUS alone also exerted a positive, albeit less, effect on BMD in the affected limb (p < 0.001 and p = 0.006, respectively). Alendronate and LIPUS cooperate to enhance BMD during metaphyseal bone healing.