Sterilization of degradabl e implant s by standard procedures may damage the parts due to the labile chemical nature of the polymers. This study examined whether the injection molding process used for the production of polymeri c parts may itself sterilize the implant due to high temperature , pressure, and shear forces applied. Poly-D ,L-lactic acid (PDLLA) and poly-L-lactic acid (PLLA) granules were contaminate d with thermoresistant spores of Bacillus stearothermophilus (ú10 5 spore s/g). Sterile and contaminated granules of both polymers were injection molded and tested for sterility. All 27 samples produced with sterile PDLLA and processed at 120
ЊC and all 18 samples produced with sterile PLLA at 200 ЊC remained sterile after injection molding and handling. However, in five out of 28 PDLLA samples and in one out of 26 PLLA samples produced with contaminate d material , spores had survived the process. In conclusion, the injection molding process could not reliably sterilize parts produced with polylactic acid granules that were heavily contaminate d with thermoresistan t organisms. However, the number of viable spores was significantl y reduced by more than 99.99%. Thus, the injection molding process might allow the autosterilizatio n of parts produced with raw material that is not heavily contaminated .