Follow-up arthroscopy was performed in 71 patients who had undergone primary repair of an acute rupture of the anterior cruciate ligament (ACL) after 6-19 months. An augmented repair was done on 61 patients and 10 patients had a nonaugmented repair. Based on the arthroscopic findings, the ACL repair was classified into three categories. Four years after the injury a clinical reexamination, including a laxity test using instrumentation and a standard knee-function test, was done on 66 patients. Arthroscopy revealed that 64 of the 71 patients (90%) had a defined ACL repair, although the repair was elongated in 37 patients. Seven patients with a nonfunctioning ACL repair had inferior knee function after 4 years. Arthroscopy also showed superficial cartilage lesions in 24 patients and meniscal pathology in 6 patients. Two patients with more advanced chondral lesions had inferior knee function. Treatment of meniscal injuries did not affect the long-term results.