This prospective study examined 50 patients who underwent ACL surgery using hamstring tendons with a modification including intra- and extra-articular reconstruction. All patients were athletes competing at a high level in various sports. Full return to sports was allowed at 4 months. IKDC score and KT-2000 were used for assessing clinical outcome at a mean of 6.4 years (5-7 years) Resumption of sport, Tegner activity score, and isokinetic test were also used. The IKDC score showed 92% of normal or nearly normal knees. Of the 50 patients 48 regained full extension, and only two had extension deficit between 0 degrees and 3 degrees. KT evaluation was less than 3 mm in 38 cases (76%), 3-5 mm in 9 (18%), and more than 5 mm in 3 (6%). In 90% of cases the patient resumed sport at the same level. The mean Tegner activity score was 8.1 (5-10). The isokinetic test showed no deficit for hamstring and quadriceps muscles. Removal of staples was necessary in eight cases (16%) due to femoral lateral bursitis. Acute reconstruction had significantly better clinical assessment of abnormal laxity and KT value. Men had significantly better results then women. This technique demonstrated a high reliability, low morbidity, low functional deficit and fast recovery using hamstring grafts.