Cytokines and osteolysis around total hip prostheses

The aim of this work is to assess the correlation between the osteolysis ar ound the prosthesis and the presence of cytokines favouring inflammation in the tissues at the interface between loosened prosthesis and bone. In this study, twenty-nine patients that underwent revision surgery were examined. Bioptic samples were collected at the interface between bone and implant b oth at the stem and socket level. Semiquantitative immunohistochemistry was performed to detect interleukin 1 alpha, interleukin 1 beta, interleukin 6 and tumour necrosis factor, cytokines that directly cause bone resorption and indirectly induce synthesis of other bone resorbing cytokines, Wear par ticles were identified and quantified by light microscopy, Radiographic evi dence for osteolysis was scored by the Engh and Bobyn score. In tissues col lected at the interface, the percentage of cells positive to IL1, IL6 and p articularly to TNF increased in relation to the tissues collected at the in terface with stable components. The cells occurring in the new capsule do n ot secrete cytokines in quantities that can be related to severity of wear. Cemented prostheses showed higher incidence of severe osteolysis, and high er levels of cytokines, It can be concluded that TNF, and to a lesser exten t IL1 and IL6, are positively related to the severity of osteolysis around the prosthesis and therefore a pharmacological treatment can be hypothesize d with anti-inflammatory or anti-cytokine drugs in order to limit or to avo id prosthesis loosening. (C) 2000 Academic Press.