QUANTITATIVE AND QUALITATIVE-ANALYSIS OF POLYETHYLENE WEAR PARTICLES IN SYNOVIAL-FLUID OF PATIENTS WITH TOTAL KNEE ARTHROPLASTY - A PRELIMINARY-REPORT

Synovial fluid from 13 knees undergoing revision total knee arthroplas ty was subjected to chemical digestion and ultrafiltration. Scanning e lectron microscopy was used to visualize high-density polyethylene par ticles filtered from the fluid, and the images were analyzed using dig ital imaging software. This data were correlated with polyethylene wea r patterns seen at the time of revision surgery. Patients' prostheses with gross polyethylene wear were differentiated from those with surfa ce deformation and burnishing. The knees had been in situ for periods ranging from 3 to 112 months, and included 6 different prosthetic desi gns. The average area of the polyethylene particles measured ranged fr om 41 to 701 mu(2), and the total number of particles identified for e ach sample ranged from 38 to 279 mu(2). The largest particle identifie d had a surface area of 17,500 mu(2). Using the fluid volume analyzed, the particle area per milliliter of synovial fluid examined was calcu lated, and values ranged from 6.22 x 10(4) to 2.06 x 10(6) mu(2)/ml. V isualization of high-density polyethylene using scanning electron micr oscopy allows greater resolution of morphologic detail than is possibl e with routine histologic examination using light microscopy. There we re trends toward increasing particle size and total particle area in p atients with gross polyethylene wear. The area of high-density polyeth ylene per milliliter of fluid in patients with gross wear was found to be statistically greater than that of patients without gross wear (p = 0.047). This technique offers a potentially valuable method of evalu ating the status of high-density-polyethylene bearing surfaces in situ using a noninvasive technique.