PROPERTIES OF TISSUE FROM AROUND CEMENTED JOINT IMPLANTS WITH EROSIVEAND OR LINEAR OSTEOLYSIS/

Levels of bone remodeling agents were measured in conditioned media fr om cultures of periprosthetic pseudosynovial membranes and related to the radiographic features of the failed joint implants. Radiographs of both cemented hip (n = 28) and cemented knee (n = 11) implants were e xamined and the pattern of radiolucency was classified as erosive, lin ear, or mixed. Similar levels of interleukin-1-beta (IL-1 beta), inter leukin-6, tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta-1, and prostaglandin E-2 (PGE(2)) were found in pseudosyn ovial membrane conditioned media from all 3 groups of hips and the kne e group (all linear). Significant correlations were evident only betwe en PGE(2) and TNF-alpha levels in the linear hip group and PGE(2) and IL-1 beta levels in the knee group. A close correlation was found betw een IL-1 beta and TNP-alpha in both linear and erosive hips. It is sug gested that coregulation of these bone remodeling agents differs with the radiographic appearance of the failed joint implants. As all the i mplants were cemented and the results contrast with those of others ob tained with pseudosynovial membrane conditioned media from cementless implants, it is considered that cement critically influences the proce ss of implant failure.