To analyze the results of the foreign body reaction to polyethylene, polymethylmethacrylate, and metal debris and effect on bone by comparing histopathologic finding of pseudomembrane (interface membrane) which was obtained from failed cemented or cementless THA by aseptic loosening.

Of total 50 cases, we analyzed results between 25 cases of cemented THA and 25 cases of cementless THA. Follow-up period between primary and revision THA was average 8 years 5 months. Tissue specimens were harvested, stained with Hematoxylin-Eosin, and examined by light microscope. Histologic study of various items was done.

The fibrous membrane between bone-to-cement or bone-to-metal could be roughly divided into three distinct histological layers in cross section histopathology. These tissues were characterized by histiocytes, infiltration of foreign body giant cells and fibrosis in all specimens, and infiltration of lymphocytes and plasma cells was relatively rare, and aggregation of polymorphonuclear leukocytes was invisible.

Although there were no significant differences in histologic findings between the regions of ten tissue specimens, there was significant difference between the degree of polyethylene or cement debris in numbers and the degree of foreign body reaction associated with increased infiltrations of giant cells, and foreign body reaction to polyethylene debris seems to be main cause of aseptic loosening of prosthesis.