Measurment of strain generated potential near bone and implant interface for assessment of osseointegration

In this study, a minimally invasive assessment using bone strain generated potential (SGP) was developed to examine the amount of osseointegration (OI) at bone-implant interface. SGP is generated by interstitial fluid flow in porous bone structure. Four experimental white New Zealand rabbits underwent pure titanium implant insertion surgery to tibia after amputation. After surgery, two animals were kept in small cages with minimal movement (Group 1). In contrast, the other rabbits were kept in a large cage that was large enough for jumping and walking (Group 2). At the end of the 5 weeks, all experimental animals were euthanized and the amputated tibia-implants were harvested. Then, a quasi-static force was applied to a bone site near the bone-implant interface for each tibia-implant specimen. Also, SGPs were measured near the interface using needle or probe electrodes. After the measurements, digital radiographs were taken to check the amount of OI for the interfaces. Full OI was observed for animals in Group 1. However, incomplete OI was found for animals in Group 2. Also, significant difference was found for mean SGP values between Group 1 and 2. The results could imply that SGP could be used as a minimally invasive assessment method to check the OI at the bone-implant interface.