Your doctor will first remove the torn ends of your ACL. Then he or she will replace the damaged ACL with the agreed-upon ACL graft: patellar, hamstring, or cadaver ACL (also known as an allograft).
Patellar ACL Graft
For a patellar ACL graft, once the damaged ACL is removed, it will be replaced with an ACL graft from your patellar tendon. To do this, another incision is made in the front of your knee, and one-third of the patellar tendon, with a piece of bone attached to either end, is removed. Because this graft is taken from the middle of the patellar tendon, the tendon is reattached with stitches that your body will absorb over time. There are typically no long-term defects after taking the graft from this location.
Hamstring ACL Graft
For a hamstring ACL graft, once the damaged ACL is removed, it will be replaced with an ACL graft from your hamstring tendons (the tendons behind your knee). To do this, another incision is made on the inside of your leg and part of the hamstring tendons are removed to form the graft. The tendon ends are then sewn together to make one solid graft.
Cadaver ACL Graft
For an allograft, once the damaged ACL is removed, it is replaced with a sterile ACL graft from a cadaver.
Regardless of the type of graft, a tunnel where the graft will eventually go is created, starting in the shinbone, going through the knee, and into the thighbone. The graft is then placed into the tunnel and usually secured into place with two screws, one in the shinbone and the other in the thighbone.
After your doctor has completed the work within your knee, all of the instruments will be removed and the fluid will be drained. The skin incisions will be closed using stitches, and a sterile bandage will be applied. A hinged knee brace may be placed to lock your knee into a straight position.