Enhancement of bone growth into porous intramedullary implants using non-invasive low intensity ultrasound

An in vivo study was designed to determine if non-invasive low intensity ul trasound could enhance bone growth into porous intramedullary implants. Ful ly porous intramedullary rods were implanted bilaterally into the ulnae of sis dogs. In each dog, one ulna served as a control and the other was treat ed with 20 min of daily ultrasound stimulation for 6 consecutive weeks. Ana lysis of serial transverse sections indicated an average of 119% more bone growth into the ultrasound-treated implants compared with the contralateral controls (P < 0.001). In each of the 6 dogs, there was a significantly gre ater amount of bone ingrowth on the ultrasound-stimulated side. These data indicate a clear potential for externally applied ultrasound therapy to aug ment biological fixation. (C) 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.