A prospective study was performed to determine the effect of a combination of a ligament-augmentation device with a bone-patellar ligament-bone allograft for the treatment of chronic rupture of the anterior cruciate ligament. One hundred and fifteen knees in 110 patients were divided into two groups. Group BLB consisted of sixty-six knees in sixty-four patients who were managed with a bone-patellar ligament-bone allograft only, and Group BLB-LAD consisted of forty-nine knees in forty-six patients who were managed with both the allograft and a ligament-augmentation device. Preoperatively, there were no statistically significant differences between the two groups with regard to fifteen variables. All patients were managed with the same postoperative program of immediate motion and rehabilitation of the knee. All patients returned for evaluation at a mean of thirty-four months (range, twenty-three to fifty-three months) postoperatively. The results were evaluated with a comprehensive rating system that assessed twenty factors. Both of these procedures significantly decreased functional limitations and symptoms and improved the level of sports activity and the over-all score. However, the use of the ligament-augmentation device did not improve the efficacy of the reconstruction with regard to any of the individual variables that were assessed or in terms of the over-all score. All but one of the patients regained an arc of 0 to 135 degrees of motion. Although the augmentation device reduced anterior-posterior displacement effectively for the first twenty weeks postoperatively (p less than 0.05), there was no difference between the groups in terms of the percentage of knees that had abnormal displacement at the latest follow-up. A new classification system was developed to determine rates of failure. The over-all rate of failure was 28 per cent (thirty-two) of the 115 knees: 29 per cent (nineteen) of the sixty-six knees in Group BLB and 27 per cent (thirteen) of the forty-nine knees in Group BLB-LAD. The difference between the two groups was not statistically significant. The addition of the ligament-augmentation device did not improve the results of allograft reconstruction in the treatment of chronic rupture of the anterior cruciate ligament. The use of either an allograft alone or an allograft combined with a ligament-augmentation device did not reduce the amount of anterior-posterior displacement satisfactorily in all of the knees.