Knee ligament injuries are relatively common and can be very debilitating. It is much more common in women than in men. One of the most common sports-related injuries is a sprain or tear in the anterior cruciate ligament which often requires surgery. During the surgery it is not possible to suture a torn ligament back together and a complete reconstruction is required. This involves the replacement of the torn ligament with a tissue graft which is taken from tendons in other parts of the leg. The replaced ligament will incorporate into the bone over a period of 8 to 12 months. The procedure is performed arthroscopically, which means that it is done through tiny incisions and is minimally invasive. Open surgery for ligament injuries are usually performed for the inner or medial supportive ligaments (MCL) or the outer or lateral ligaments referred to as the posterolateral corner.