BACKGROUND: The main objective of the present study was to investigate chemical 
composition and possible cyto/genotoxic potential of several medical implant 
materials commonly used in total hip joint replacement.
METHODS: Medical implant metal alloy (Ti6Al4V and CoCrMo) and high density 
polyethylene particles were analyzed by energy dispersive X-ray spectrometry 
while toxicological characterization was done on human lymphocytes using 
multi-biomarker approach.
RESULTS: Energy dispersive X-ray spectrometry showed that none of the elements 
identified deviate from the chemical composition defined by appropriate ISO 
standard. Toxicological characterization showed that the tested materials were 
non-cyto/genotoxic as determined by the comet and cytokinesis-block micronucleus 
(CBMN) assay. Particle morphology was found (by using scanning electron and 
optical microscope) as flat, sharp-edged, irregularly shaped fiber-like grains 
with the mean particle size less than 10µm; this corresponds to the so-called 
"submicron wear". The very large surface area per wear volume enables high 
reactivity with surrounding media and cellular elements.
CONCLUSIONS: Although orthopedic implants proved to be non-cyto/genotoxic, in 
tested concentration (10μg/ml) there is a constant need for monitoring of 
patients that have implanted artificial hips or other joints, to minimize the 
risks of any unwanted health effects.
GENERAL SIGNIFICANCE: The fractal and multifractal analyses, performed in order 
to evaluate the degree of particle shape effect, showed that the fractal and 
multifractal terms are related to the "remnant" level of the particles' toxicity 
especially with the cell viability (trypan blue method) and total number of 
nucleoplasmic bridges and nuclear buds as CBMN assay parameters.