A torn anterior cruciate ligament can result in an unstable knee. Depending on symptoms and activity, the surgeon may present several options to repair or replace a torn ACL. The replacement options include using the patient's knee tendons or using tendons from a cadaver. The surgical procedure will require anesthesia. All methods are done through an arthroscope which is a tiny camera inserted into the knee.
Repair
When the ligament is intact but a large piece of bone is pulled away from the tibia, repair is done by screwing the bone piece into place. If the ligament is only partially torn and provides stability to the knee it may be left in place. If the ligament is completely torn, it is unlikely to heal by suturing the ends together and a replacement is recommended, according to the American Academy of Orthopaedic Surgeons.
Replacement
For all ACL replacement surgeries, the torn ACL tendon is removed. A 1-inch incision is made over the tibia, then 1 cm-holes are drilled into the the lower leg bone, or tibia, and the femur which is the thigh bone. The surgeon aligns these holes to simulate the normal course of the ACL ligament. According to AAOS, the most common ACL replacement grafts are patella tendon or hamstring tendons. Some surgeons use a portion of the quadriceps tendon. The graft may be taken from the injured leg or opposite leg. The surgeon and patient need to discuss the patient's health, job and sports activities to determine which graft choice is right for them.
Patella Tendon
For the patella tendon graft, the middle-third of the tendon is used along with attached 1-inch-by-1-cm pieces of bone from the patella and from the tibia. The bone ends of the graft are placed in the holes created in the tibia and femur. The AAOS cites patella fracturing as a risk of this surgery. This graft creates a scar over the front of the knee.
Hamstring Tendon
Two of the hamstring tendons, the semitendinosus and gracilis, are used for the hamstring graft. The incision is made over the tibia where the drill holes were created. The AAOS explains the risks of this surgery include the graft loosening or graft rupture. Semitendinosus, semi-T, STGT and occasionally gracilis are other names used for this surgery.
Quadriceps Tendon
The quadriceps graft uses a 1-inch-by-1-cm piece of bone from the patella and the middle-third of the quadriceps tendon. The scar is over the top portion of the knee. The AAOS notes the risks of this surgery include the patella fracturing.
Allograft
Allograft is the medical term for a graft from another person. For ACL surgery, allograft refers to cadaver tendons. The allografts used are the achilles tendon and the patellar tendon. The achilles tendon graft has a portion of the heel bone attached while the patella tendon graft has two pieces of bone attached. According to AAOS, the risks of these grafts include slow healing, graft rupture and infection. There is no additional scar.
References
- "AAOS Comprehensive Orthopaedic Review"; Lieberman, J, ed. Cruciate and Collateral Ligament Injuries. Ch. 109, Marx RG, Parker RD, Matava MJ and Sekiya JK Rosemont, IL.:AAOS. 2009
- "AAOS Comprehensive Orthopaedic Review"; Lieberman, J, ed. Tendons and Ligaments. Ch. 7 . Thomopoulos, S. Rosemont, IL.:AAOS. 2009
- "Skeletal Trauma; Basic Science, Management and Reconstruction"; Browner, BD, Levine AM, Jupiter JB, and Trafton, eds. . Dislocations and Soft Tissue Injuries of the Knee. Ch. 55 Siliski, JM Philadelphia, PA: Saunders, Elsevier 2003
