EFFECT OF NONINVASIVE LOW-INTENSITY ULTRASOUND ON BONE-GROWTH INTO POROUS-COATED IMPLANTS

Noninvasive low intensity ultrasound has been shown to be an effective means of accelerating bone fracture healing in both animal and clinic al studies. An in vivo canine study was designed to determine if nonin vasive low intensity ultrasound could influence the rate and extent of bone growth into porous-coated implants. Twenty-two pairs of fully po rous transcortical implants were inserted bilaterally into the femora of 12 dogs. In each dog, one femur served as a control and the other w as subjected to daily ultrasound stimulation for 2, 3, or 4 weeks. Ove rall, the ultrasound-stimulated implants demonstrated an 18% increase in bone ingrowth compared with their contralateral controls (p = 0.02) . Noninvasive low intensity ultrasound had its greatest effect in the first 2-3 weeks of stimulation. At 2 and 3 weeks, the ultrasound-stimu lated implants showed 21 and 16% more ingrowth than their respective c ontralateral controls. Because noninvasive low intensity ultrasound ha d a positive effect on bone ingrowth in this experimental investigatio n, further research is suggested to assess the clinical potential for application to noncemented porous-coated total joint replacements.