The purpose of this study was to evaluate arthroscopically the type, localization and prevalence of the meniscal and chondral lesions accompanying complete rupture of the anterior cruciate ligament (ACL) in patients who elected not to restrict their daily activities after the initial trauma. The size of the chondral lesions was also evaluated. Our second aim is to analyze the effects of age, time from injury, and both age and time from injury in the presence or absence of accompanying lesions in these patients. The localization and type of the accompanying lesions of 317 knees with complete rupture of the ACL were recorded by the same observer. We applied therapeutic arthroscopy to all patients after their first visit to our clinic. All of the patients were military personnel and their history revealed that they had elected to not restrict their occupational activities after the first trauma causing ACL insufficiency. We defined the first 6 week period after the initial trauma as the acute, 6 weeks to 12 months as the subchronic and 12 months or longer as the chronic period. The average time from injury to arthroscopy for these patients, who were all male, was 19.4 +/- 20.3 months. Eighty-one percent of the patients had at least one meniscal tear, and 45.1% had at least one chondral lesion. The mean ages at the time of surgery of patient groups with or without medial and lateral menisci lesions were compared, and no statistically significant difference was determined. In the chronic period, the relative risk (RR) values of meniscal tears were 7.75 for medial and 2.40 for lateral. The group consisting of patients with chondral lesions was compared with the group of patients without chondral lesions in terms of their ages and the time from injury to arthroscopy, and the difference was statistically significant. The RR value for patients with co-existence of at least two lesions was 1.761 for more than 30 years of age. The RR values for at least two lesions were 2.356 for the subchronic and 14.909 for the chronic group when compared to the acute group. The RR values in patients more than 30 years of age in the chronic group were 13.58 for medial meniscus, 3.21 for lateral meniscus and 71.88 for chondral lesions when compared to patients less than 30 years of age in the acute group. It is important to note that the combined effects of advanced age and prolonged time from injury in patients who elected to not restrict occupational activities are more severe due to the increase in the occurrence of intraarticular lesions accompanying ACL insufficiency as compared to their separate effects.