Volume 5, Issue 2 (February 2008)
Analysis of Endotoxin Residues on Cleaned Implant Materials
In this study we have investigated the effect of bacteria-containing metal working fluids on the biological residues, which may be found on orthopedic implants. Thus, test coupons and unfinished implants made from commercial pure titanium and titanium aluminum niob were immersed in metal-working fluids containing Pseudomonas pseudoalcaligenes bacteria. Subsequently, these samples were cleaned by means of a multi-tank industrial cleaning scheme, which is commonly used in the medical device industry. The samples were then analyzed with a rapid screening test for bacteria, a Ps. pseudoalcaligenes, specifically, quantitative polymerase chain reaction (PCR) protocol for DNA detection and the Limulus Amebocyte Lysate gel clot test for endotoxins. None of the test pieces showed any biological residues after the cleaning process. There is no increased risk regarding biological residues for metallic implants that were in contact with bacteria containing metal-working fluids if the devices are properly cleaned. A higher risk for biological contamination would more likely arise from any processes after the final cleaning, i.e., from handling, environmental factors, or packaging of the materials.