EFFECT OF FEMORAL-HEAD DIAMETER ON TISSUE CONCENTRATION OF WEAR DEBRIS

Although several studies have reported the physical properties of debr is particles in tissues adjacent to failed total joint implants, few h ave correlated the results of particle analysis with other clinical an d implant variables believed to influence implant wear. We retrospecti vely analyzed 41 fibrous membranes (from 35 patients) adjacent to fail ed acetabular cups from a single manufacturer and studied the relation ship between three different femoral head sizes (26, 28, and 32 mm) an d the characteristics of wear debris in the adjacent tissues. All tota l hip prostheses consisted of modular cobalt-chromium alloy femoral he ads articulating with titanium-alloy-backed ultrahigh molecular weight polyethylene (UHMWPE) acetabular components from a single manufacture r. Large femoral head diameter (32 mm) was found to correlate signific antly with large particle size (diameter and surface area, p < 0.05), high tissue concentration of particles (particle volume/gram of tissue , p < 0.01), and high rate of particle production (particles volume/mo nth, p < 0.05). The results of these quantitative assays support the f indings of radiographically based clinical studies that show higher vo lumetric wear associated with 32 mm femoral head components. (C) 1997 John Wiley & Sons, Inc.