Examination of factors influencing intramedullary reaming into femurs

This preliminary study explores material surface chemistry modifications to optimize intramedullary (IM) reaming into femurs. Understanding and quantifying the effects of surface chemistry will allow beneficial new material choices. M2 standard High Speed Steel Straight Shank Straight Fluke chucking reamers of 5/32" or ~4mm diameter were reamed into RenShape® -BM5460 (bone analogs) blocks for the investigation. Sterilizations (Steam Autoclave and Radio Frequency Glow Discharge Treatment) and low friction coatings (Octadecyltrichlorosilane or ODS and 3-Hepta-fluoropropyl-methyldichloro- silane or 3-HEPT) were the surface modifications so far pursued in this study. The effects due to the presence of possible transfer films from bone analogs during reaming on cutting efficacies have been investigated on a custom made Orthopaedic Rotational Cutter Analysis System (ORCAS) test system. The results preliminarily suggest a transfer film from the bone analog resulting in reduction of peak loads and peak toques through repeated use. The low-friction coatings have induced lower peak loads and comparable peak torques, suggesting a corollary between low friction coatings and lower surgical efforts required.