ACL reconstruction in the Division of Orthopaedic surgery at Queen's is currently being performed arthroscopically assisted. The resultant function of the reconstructed ligament is greatly influenced by the placement of the transosseous tunnels, which are tunnels in the bones through which the grafts pass. Presently the placement of the tunnels is being judged from arthroscopically identified anatomical landmarks within the joint. The result is incidence rates of misplaced tunnels as high as 40%. Computer assisted tunnel placement would aid in the correction and reproducibility of anatomic tunnel placement. The objective of this study is to conduct a prospective, randomized trial comparing clinical and radiographic outcomes in subjects who receive either a patella or hamstring tendon graft to reconstruct a chronic tear of the anterior cruciate ligament. All subjects will be further randomized into a computer-assisted or a conventional arthroscopic surgical group to allow investigators to compare the precision and accuracy of tunnel placement between these surgical approaches. The main question under investigation is: does the increased accuracy of computer-assisted surgery make a clinical difference to the laxity of the reconstructed knee, and is the laxity further influenced by the type of tendon graft received?