Wear particles analysis of Ti alloy femoral heads with diamond-like carbon coating

Objective To identify the characteristics of wear particles generated by Ti alloy femoral head coated by diamondlike carbon (DLC) film on hip simulator． Methods Three groups of artificial femoral head were studied in this research, Group A: CoCrMo alloy femoral head against ultra-high molecular weight polyethylene (UHMWPE) acetabular cup (CoCrMo- UHMWPE，Zimmer, America); Group B: Ti alloy femoral head with diamond-like carbon coating against UHMWPE acetabular cup (Ti-DLCUHMWPE, Jinghang, China); Group C: CoCrMo alloy femoral head against UHMWPE acetabular cup (CoCrMo- UHMWPE, Jinghang, China)． Fetal bovine serum lubricant was collected respectively from each group after 0．33 million circles (mc)． Then the bovine serum was digested by adding acid and filtered through polycarbonate． The characteristics of particles of each group were determined by scanning electron microscope-energy dispersion X-ray analysis (SEM-EDX)． The size, shape and number of particles were measured with Image-Pro Plus6．0 on SEM pictures． Results The energy dispersion X-ray analysis (EDX) showed that the main element was carbon． No marked cobalt, chromium, molybdenum, titanium was detected． Over 60% of the particles were globe-like in all groups． The particle size varied from 0．1 to 40μm, most of which ranged from 0．1 to 1μm． Particles with diameter over 1μm had a large proportion in volume． The number of particles on filter in group B was less than other groups． Conclusion The wear particles are predominately UHMWPE particles． Artificial femoral heads with DLC coating produce less wear particles．