It has been shown in vitro that human monocytes can phagocytose submicron polyethylene wear particles generated from total hip arthroplasties (THA) with highly cross-linked polyethylene inlays. The aim of our study was to detect the presence and possible phagocytosis of such particles in peripheral blood monocytes of patients with respective THA. All patients were operated using the same implant, the cementless SL Plus stem; Bicon cup and a cross-linked polyethylene insert Rexpol (Smith and Nephew). Besides clinical and radiographic check-up, blood samples were collected at follow-up and analyzed by flow cytometry. Polyethylene can be identified by its auto fluorescence when stimulated by a laser with the wavelength of fluorescein isothiocyanate (FITC). Presence of wear particles in monocytes was identified by determination of their size and granularity. Some samples were scrutinized by confocal laser scanning microscopy to correlate the intracellular position of the particles. Blood samples of patients without total joint replacement served as controls.Introduction
Patients and methods