Structural changes and reactions of surrounding tissues after implantation could contribute loosening in orthopaedic surgery. The aim was to investigate the effect of orthopedic implants on fatty acid (FA) profile of surrounding tissues. New Zealand rabbits (n=40) were assigned randomly to one of four commonly used orthopaedic implants (ceramic, titanium, polyethylene and stainless steel) and sham. One month after surgical intervention, the pseudomembranes developed in response to applications were harvested for FA and histopathology. The cellular FA profile was determined using gas chromatography. Fibrotic tissues developed in response to all implants. Fatty acid profile of cells surrounding implanted tissues was different from that of periosteoum (sham group). C was the most prevalent FA in all samples. C was absent in the stainless steel 16:0 16:1 group, whereas C was present in only in the control and ceramic groups. Fatty acid profile of the 17:1 polyethylene group was similiar to that of the ceramic group. More significantly, tissues facing titanium and stainless steel contained neutophil infiltration, lympho-plasmocytes at the center of fibrotic connective tissues, macprophages and gigantic cells. As compared with ceramics and polyethylene, metallic materials may prone to greater risk for loosing due to remarkeable structural changes in surrounding tissues facing implants.