Between April 1989 and July 1996, 217 anterior cruciate ligament reconstructions using a synthetic ligament of polyethylene terephthalate (PET Trevira-- hochfest) were performed. 160 (74%) cases have been followed-up with a mean time of 4.8 years (1.0-8.3) and evaluated by the IKDC standard knee ligament evaluation form. Altogether 88% excellent and good results were found. The best outcomes involved isolated ACL tears and reconstruction within a few month. The amount and intensity of lasting symptoms depended mostly on osteoarthrotic changes (chondral and meniscal lesions) and correlated with the interval between injury and reconstruction. All findings are presented in detail and critically discussed.