Stimulation of Titanium Implant Osseointegration Through High-Frequency Vibration Loading is Enhanced when Applied at High Acceleration

Low-magnitude high-frequency loading, applied by means of whole body vibration (WBV), affects the bone. Deconstructing a WBV loading stimulus into its constituent elements and investigating the effects of frequency and acceleration individually on bone tissue kinetics around titanium implants were aimed for in this study. A titanium implant was inserted in the tibia of 120 rats. The rats were divided into 1 control group (no loading) and 5 test groups with low (L), medium (M) or high (H) frequency ranges and accelerations [12–30 Hz at 0.3×g (F_LA_H); 70–90 Hz at 0.075×g (F_MA_M); 70–90 Hz at 0.3×g (F_MA_H); 130–150 Hz at 0.043×g (F_HA_L); 130–150 Hz at 0.3×g (F_HA_H)]. WBV was applied for 1 or 4 weeks. Implant osseointegration was evaluated by quantitative histology (bone-to-implant contact (BIC) and peri-implant bone formation (BV/TV)). A 2-way ANOVA (duration of experimental period; loading mode) with α = 0.05 was performed. BIC significantly increased over time and under load (p < 0.0001). The highest BICs were found for loading regimes at high acceleration with medium or high frequency (F_MA_H and F_HA_H), and significantly differing from F_LA_H and F_MA_M (p < 0.02 and p < 0.005 respectively). BV/TV significantly decreased over time (p < 0.0001). Loading led to a site-specific BV/TV increase (p < 0.001). The highest BV/TV responses were found for F_MA_H and F_HA_H, significantly differing from F_MA_M (p < 0.005). The findings reveal the potential of high-frequency vibration loading to accelerate and enhance implant osseointegration, in particular when applied at high acceleration. Such mechanical signals hold great, though untapped, potential to be used as non-pharmacologic treatment for improving implant osseointegration in compromised bone.