PERIPROSTHETIC MICROVASCULATURE IN LOOSENING OF TOTAL HIP-REPLACEMENT

This study was performed to quantitate vascularity in periprosthetic t issues of loose total hip replacements (THRs), because most likely rev ascularization and endothelial cells are important for implant osseoin tegration and loosening. Interface and pseudocapsular tissue samples o btained from loose THRs were stained with an immunohistochemical label ling (ABC technique) for von Willebrand factor. Non-inflammatory synov ial samples served as controls. The results were quantitated by morpho metry using the Kontron image analysis system. Evaluation of the mean endothelial index (ET; positively stained area mu m(2)/mm(2) of tissue ) revealed that in the control samples synovium was better vascularize d than was the case in the cellular areas of the periprosthetic pseudo capsule (P = 0.0008) and interface (P = 0.0004) of loose THRs. There w as no significant difference between mean EI of cellular areas in the interface and that of the pseudocapsule (P = 0.24). In the interface t he vascularity was irregular. Vascular injury and decreased blood supp ly seem to occur at the implant-host interface, which may be one of th e reasons for insufficient implant osseointegration and loosening.