Comparison between radial fretting and dual-motion fretting features of cortical bone

Fretting tests were carried out to compare the effect of radial and dual-motion modes on wear of cortical bone. A titanium ball was rubbed against fresh human cortical bone under controlled load and motion test conditions. Dual-motion fretting mode produced more severe damage than radial fretting, with more debris occurring at the worn surface. Cracks were abundant in radial fretting and they were significantly affected by the microstructure of cortical bone; this effect was not obvious in the case of the dual-motion fretting mode. Radial fretting test could be used to evaluate the anisotropy of material and crack propagation of brittle cortical bone.