Effect of Zoledronic Acid on Early Osseointegration of Porous Implant in Rabbit

Sur, Yoo Joon; Kim, Hyoung Min; Song, Seok Whan; Yoo, Nam Jin

Abstract

PURPOSE
The purpose of this study was to determine whether intravenous injection of the zoledronic acid could promote osseointegration of the porous implant inserted into the rabbit medullary cavity.
MATERIALS AND METHODS
A rabbit intramedullary osseointegration model was used. A specially designed porous nitinol implant (Bio-Smart, Sungnam, Gyeonggi-do, Korea) was inserted in the right distal femur of twenty six rabbits. They were randomized into the control or the experimental groups. In the control group, an intravenous injection of normal saline 2 ml/kg (Daihan Pharm, Seoul, Korea) was given at the end of the operation. In the experimental group, an intravenous injection of zoledronic acid 0.1 mg/kg (AclastaG(R) 2 ml/kg, Norvatis, Stein, Switzerland) was given at the end of the operation. Six weeks later, all animals were sacrificed and undecalcified histologic sections were prepared. Then, histomorphometric measurement of bone affinity index (%) and bone ingrowth area rate (%) was carried out.
RESULTS
Six rabbits were excluded due to death and wound infection. Nine rabbits in the control group and eleven rabbits in the experimental group were included for the analysis. The bone affinity indices were 19.9+/-7.9% in the control group, and 28.4+/-7.2% in the experimental group. Although there was no statistical significance (p=0.056), the bone affinity index of the experimental group was higher than that of the control group. The bone ingrowth area rates were 8.7+/-3.7% in the control group, and 12.1+/-4.1% in the experimental group (p=0.046), indicating zoledronic acid had an positive effect on the promotion of bone ingrowth into the porous implant.
CONCLUSION
In our rabbit intramedullary osseointegration model, intravenous injection of the zoledronic acid promoted early osseointegration of the porous implant. Zoledronic acid might be useful to promote the early osseointegration of the joint replacement implants.