sports injury centre





Question:1. What is the ACL and what does it do?

Answer :
  • The anterior cruciate ligament (ACL) connects the femur (thigh) bone to the tibia (leg) bone in the center of the knee joint.
  • The ACL is important during daily activities but absolutely critical to the stability of the knee during sports and athletics.


Question:2. What is the native anatomy of the ACL?

Answer :
  • The ACL is made up of two functional bundles of tissue, the anteromedial (AM, front) and posterolateral (PL, back) bundles.
  • The AM bundle of the ACL primarily controls anterior (forward) movement of the tibia underneath the femur, and the PL bundle controls rotational stability of the knee, such as in turning, pivoting, twisting, running, and jumping.
  • Here is a closer look at the attachment sites – we can see the ACL attachment site on femur (upper) and AM and PL bundles and their attachment on the tibia (down).

Question: 3  How is an ACL tear diagnosed?

  • Tear of the ACL can be diagnosed by a history of trauma to the knee (contact or non-contact) and physical examination. MRI scan can confirm the diagnosis, but it is not absolutely necessary.
  • At the time of arthroscopic surgery, severe stretching or complete tearing of the AM and PL bundles of the ACL may be observed.


Question: 4 Is surgery necessary for ACL tear?

Answer : Yes, an intact ACL is needed for a stable knee for performing activities of daily living like running, jumping, stair climbing and more so in sporting activities.
  • There is a risk for damage to the menisci (cushion like structures) and articular cartilage coating inside the knee joint with each subluxation event. This damage can lead to degenerative arthritis.
  • There is a risk of injury to other ligaments of knee also.


Question: 5 Can the ACL be repaired or does it have to be reconstructed?

Answer : In general, the fibers of the ACL can not be sewn back together again (or repaired ‘primarily’). This is due to irreversible stretching and damage to the ligament sustained at the time of injury. Therefore, damaged ligaments are removed and replaced with new ones.


Question: I just tore my ACL—when will I be ready for surgery?

Answer: In general, there are three criteria that must be met before the ACL can be surgically reconstructed:
  • Swelling in the knee must go down.
  • Range-of-motion (flexion and extension) of the injured knee must be nearly equal to the uninjured knee
  • Good Quadriceps muscle control must be present (ability to do straighten the knee)


Question : 6 What surgical techniques are used for ACL reconstruction?

Answer : A standard technique of ACL surgery during a “single bundle” reconstruction involves removing the remnant of torn ACL. A drill guide is then used to drill a single tunnel on both the tibia and femur. A single ACL graft is then passed through the tunnels and fixed on either side.

Question : 7 Do we perform anatomic single bundle ACL reconstruction?

Answer : There are a few scenarios where we prefer to perform single bundle surgery:
  • Patient has a very small native ACL insertion site. This typically can only be determined at the time of surgery.
  • Patient is still growing and his or her growth plate is not closed.
  • Patient has severe arthritis.
  • Patient with multiple knee ligament injuries or knee dislocation In females generally, because of smaller knees.


Question : 8 Why is Anatomic Double-Bundle ACL reconstruction performed instead of Single-Bundle?

Answer : There is a significant amount of scientific evidence supporting double bundle surgery:
  • The ACL is composed of two functional bundles, the anteromedial (AM) bundle and the posterolateral (PL) bundle, not just one.
  • Between 10% and 30% of patients complain of pain and residual instability following Single-Bundle ACL reconstruction.
  • Arthritis has been observed on x-rays in up to 90% of patients at long-term follow-up after Single-Bundle ACL reconstruction.
  • Single-Bundle ACL reconstruction does not adequately restore normal knee stability, particularly tibial rotation.
  • Anatomic Double-Bundle reconstruction better restores knee stability compared to Single-Bundle reconstruction. To better understand how “Double-Bundle” ACL reconstruction has evolved from “Single- Bundle” surgery, one should consider a door hinge. A door with one hinge is like a Single- Bundle reconstruction—it will open and close, but the hinge is required to work excessively. Over time the hinge will loosen and the door will wobble. In comparison, a Double-Bundle reconstruction is like a door with two or three hinges. The work is shared between the hinges, and the door can open and close smoothly for long periods of time without falling apart.


Question : 9 What are the details of the surgery?

Answer : For ACL reconstruction, we typically use four small incisions:
  • Three arthroscopic incisions: AL—Anterolateral Portal, AM— Anteromedial Portal, AMP—Accessory Medial Portal.
  • One tibial incision for the bone tunnels and harvesting graft for making ligaments.
  • Occasionally, an additional incision is made on the lateral (outer) aspect of the knee joint over the femur to help secure the graft for crosspin fixation.
  • ACL reconstruction usually takes 30 to 45 minutes.
  • First, the insertion sites of both bundles (AM and PL) of the old ACL are marked on the femur and tibia.
  • The injured ACL is then removed with arthroscopic equipment.
  • Care is taken to place the new tissue grafts in the exact position of the original bundles of the ACL, creating an “Anatomic” reconstruction.
  • For each bundle of graft tissue (AM and PL) one tunnel is created in the femur and one in the tibia (total = 4).
  • Each tunnel measures anywhere from 6 to 8mm in diameter, and this dictates final graft size
  • Tunnels are created by drilling over guide wires, and sutures are passed
  • The grafts are then passed through the tunnels and fixed to the femur and tibia with a combination of tight-rope or cross-pin and screws.
  • After Double-Bundle reconstruction, most patients achieve excellent range ofmotion, typically equal to the other knee.


Question : 10 Is it possible to tear just one bundle?

Answer :
  • Yes – this is rare but does happen
  • Clinically an isolated tear of the:
  • AM bundle leads to anterior-posterior instability
  • PL bundle leads to rotatory instability
  • In either case we save the intact bundle and “augment” the ACL with a single bundle reconstruction – either the AM or PL, whichever one is torn.

Question : 10 Where do the grafts for ACL reconstruction come from?

Answer :
  • The graft tissue come from your own body (autograft)
  • Autograft options include: Hamstrings Tendons, Quadriceps Tendon, and Patella Tendon (BTB).
  • When possible we prefer to use Hamstring Tendon or Quadriceps Tendon.


Question : 12 Why bother with an “anatomic” or “double-bundle” reconstruction if it takes longer, with respect to operating time and time to return to sports?

Answer : This method of ACL reconstruction (anatomic) regardless of whether we do single (30%) or double bundle surgery is meant to reproduce YOUR OWN ACL, both in regard to ligament placement and ligament size. We believe that this more closely reproduces “your” native anatomy. In addition, there are certain benefits like rotational stability for a double bundle ACL reconstruction.


Question : 13 What happens to the knee joint, if anatomy is not restored?

Answer : The answer to this should be considered in two stages: the short term and the long term. In the short term – a well-placed ACL reconstruction allows good restraint to both AP (front to back) and rotational stability. This “macro-stabilization” allows patients to feel stable both subjectively and objectively and is key to returning to sports at a high level. In the long term – subtle or “micro” motion about the knee likely accounts for the increased incidence of early arthritis in the affected knee (in addition to the damage from the initial trauma to that knee). Because my bone and ligament anatomy is different from yours, the forces across my ACL will be different. Because of thisvariation, a ligament meant for me will not work as well for you. Although this may be close enough to reproduce the “macro-stability” mentioned above, this will not stabilize the micro-motion that occurs around the knee in the long term.


Question : 14 Do we do a double-bundle reconstruction in every patient with a torn ACL?

Answer : No, we don’t. We perform single bundle ACL surgery on 30% of patients. There are cases (taking the rest of the knee and patient into account) where single bundle is better: 1) too small of a knee to safely place two bundles (technical issue), 2) Open growth plates 3) severe arthritic changes, 4) multiple ligament surgery. Again, your ACL surgery should be what is best for YOU as a patient and this includes age, activity level, bony anatomy, size of knee, open vs. closed growth plates, etc….


Question: 15 When can I go back to Sports?

Answer : Generally, jogging begins at 3-4 months after surgery. Sport specific training begins at 6 months. Return to competition is allowed at 9-12 months following surgery. Remember, returning earlier increases the chances of ACL re-rupture. Although you may feel fine otherwise, biologically, the ACL graft takes about 9 months to heal.


Question: 16 Is rehab any different after a double bundle reconstruction?

Answer :No. All aspects of rehab are the same for single and double bundle ACL surgery.


Question :17 If I’ve already failed a previous ACL reconstruction, can I still do a double bundle ACL reconstruction on my knee?

Answer : Yes. In fact, if you’ve already failed single bundle ACL reconstruction, a double.
Last Updated : 21/10/2017:13:03