ANALYSIS OF LYMPH-NODES FOR POLYETHYLENE PARTICLES IN PATIENTS WHO HAVE HAD A PRIMARY JOINT REPLACEMENT

Polarized light microscopy has been used for more than forty years to identify polyethylene particles in histological specimens; however, fe w investigators have assessed the specificity of this technique. We ex amined specimens from dissected lymph nodes for the presence of strong ly birefringent particles resembling polyethylene. Twenty-seven patien ts had dissection of lymph nodes after a total joint replacement (Grou p 1), and a control group of eighteen patients had dissection of lymph nodes before a total joint replacement (Group 2). Specimens from both groups of lymph nodes were examined under plain and polarized light. The presence of strongly birefringent particulate debris was graded fr om 0 to 4. Twenty-one (78 per cent) of the twenty-seven patients in Gr oup 1 and eight of the eighteen patients in Group 2 had strongly biref ringent particles in the lymph nodes. Our results demonstrate that, in the assessment of the systemic dissemination of polyethylene in the l ymphoreticular system, polarized light microscopy has important limita tions. More refined techniques employing polarized light and other met hods of physical and chemical analysis may be necessary to identify po lyethylene particles accurately within the lymphoreticular system and periprosthetic tissue.