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ACL Injury and Repair


The following article describes, in detail, the anatomy of the anterior cruciate ligament (ACL), what happens when a tear occurs, and treatment options for ACL injuries, including surgeries performed, complications often incurred, outcomes, and rehabilitation. This information is to be used by patients in order to allow them to make the best-informed decisions regarding the management and treatment of ACL injuries.



The ACL is one of the most frequently injured ligaments in the knee. Most often, those at the highest risk of suffering from an ACL injury are those who play riskier sports, such as football, rugby, and winter sports such as skiing and snowboarding. Basically, any sport or activity that forces the knee to deal with constant, intense activity puts someone at risk for an ACL injury.

Somewhere in the neighborhood of 50% of ACL injuries occur in conjunction with damage to the meniscus, cartilage, and/or other ligaments. What’s more, bone bruises may occur beneath the cartilage surface, further amplifying any pain or discomfort experienced. These bruises may be visible only with magnetic resonance imaging (MRI) and may tip doctors off to articular cartilage injury.




Nonsurgical Treatmemt

With nonsurgical treatment, there are times when progressive physical therapy and rehabilitation can bring the knee’s overall condition close to what it was prior to the injury occurring. Patients will also be taught how to preserve knee stability once physical therapy has concluded. In a lot of cases, a hinged knee brace may be necessary to preserve stability. Unfortunately, those who opt out of surgery run the risk of making their ACL injury worse or creating a new injury altogether.
When an ACL tear occurs in conjunction with other knee injuries, surgical treatment is typically advised. In some cases, however, deciding against surgery is a completely rational and understandable decision. Patients who are dealing with the following situations may experience success in managing their injury:

● Partial tears where no instability issues exist
● Complete tears that feature minimal instability such that low-demand sports/activities are still possible (will likely need to give up higher-demand sports/activities)
● Those who live sedentary lives/those who perform light/limited manual work
● Those whose bones are still growing (children)

Surgical Treatment

Contrary to popular belief, ACL tears are not fixed by simply sewing the torn pieces of ligament back together. The reason for this is due to the fact that those kind of fixes will eventually fail after some time. Instead, the torn part of the ACL is replaced by what is known as a tendon graft. In essence, it involves taking tendon from another part of your body and using it to repair the tear.

● Patellar tendon autograft (autograft comes from the patient)
● Hamstring tendon autograft
● Quadriceps tendon autograft
● Allograft (taken from a cadaver) patellar tendon, Achilles tendon, semitendinosus, gracilis, or posterior tibialis tendon


Surgical Procedure

Prior to any surgery being conducted, patients are sent to physical therapy in almost all cases. This is so because performing surgery on patients who have a swollen knee that lacks full range of motion may result in complications after surgery is complete. It can take three weeks or more from the time of injury before full range of motion is regained and surgery can be conducted. If other ligaments are injured, patients may be asked to allow for time for those to heal prior to ACL surgery being performed.

The patient, aided by both the surgeon and the anesthesiologist, will select the anesthesia utilized for surgery. Many patients benefit from an anesthetic block of the nerves because it helps to decrease pain in the leg and knee after surgery.

After succumbing to the effects of anesthesia, a patient’s knee undergoes yet another examination. This last examination is necessary in order to determine that the ACL is, in fact, torn, and also to look for any other knee ligaments that may also need to be repaired in surgery, or treated afterwards.

If the final physical exam suggests that the ACL is torn as has been suspected, the preselected tendon will be harvested (for autografts) or thawed (for allografts) and sized for the patient.

Once the graft is readied, the surgeon will place an arthroscope into the knee joint. Small (1 cm. ) incisions, or portals, are made near the front of the knee in order for the surgeon to be able to insert the arthroscope and other surgical instruments into the knee. Any meniscus or other cartilage injuries will be prepared and the torn stump of an ACL will be removed.

After surgery, X-rays will be taken in order to show the grafts position and any bone plugs with metal screws. Metal screws may be needed in order to aid the patient’s recovery and ultimately accelerate recovery.

In most ACL reconstruction situations, bone tunnels are drilled into the tibia and femur in order to hold the ACL graft in the proper place. Then, a long needle is passed through the tunnel of the tibia and up the femoral tunnel. Before being placed, the graft is kept under tension and is fixated in place with interference screws, spiked washers, posts, and/or staples. These items, when used in ACL reconstruction, are usually never removed.

There are variations to this surgical technique known as “two-incision,” “over-the-top,” and “double-bundle.” Whether any one of these other techniques is used will be a determination made by the surgeon or other circumstances.

Prior to the surgery’s completion, the surgeon will probe the graft to make sure it has adequate tension and that it will allow for full range of motion of the knee. They may also perform the Lachman’s test to assess the overall stability of the graft. The skin will be resealed and dressings (which may include a cold therapy device or brace) are applied. Almost always, the patient will be able to return home shortly after they awake from the effects of anesthesia.