Bones, Joints and Muscles Conditions / Diagnoses

ACL (Anterior Cruciate Ligament) Tear

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What is the ACL?

Four main ligaments hold the knee joints together: the medial collateral ligament, lateral collateral ligament, anterior cruciate ligament and posterior cruciate ligament. Injury to the cruciate ligaments is more devastating than the collateral ligaments because the collateral ligaments have some potential for healing without surgery. The cruciate ligaments have virtually no capacity for healing once they are torn.

ACL tears occur two to six times more frequently in females than in males involved in the same amount of sports participation. However, due to the higher level of male participation in contact and collision sports, the overall number of cruciate ligament injuries remains higher in males. ACL injuries can be associated with injuries to meniscal cartilage and the surface cartilage in the knee, which can complicate matters.

What causes a torn ACL?

The cause of most ACL tears is a sudden, abrupt change in force to the knee. This can occur during an unexpected cutting move during sports, or when landing from a jump during basketball. Recent evidence demonstrates that most of these injuries are non-contact and do not involve a collision with another player.

What are the symptoms of a torn ACL?

Typically, the knee gives out, and the athlete hears a pop and collapses in agony. Most athletes with an ACL tear cannot resume play and must be helped off the field or court. The knee usually swells very quickly. At the emergency room, X-rays will be taken, which usually come back normal, with swelling on the knee. The diagnosis is typically a knee sprain, and the athlete is placed in a knee brace and instructed to follow-up with a sports medicine specialist in the next few days.

Treatment

The initial treatment consists of ice during the first 24 to 48 hours, elevation, rest, compression, such as an ACE" wrap, and immobilization with a knee brace. Crutches are usually needed. A pain medication, such as Tylenol" with codeine, Ibuprofen or Vicodin", is often prescribed. The patient may have to miss a few days of school after the initial injury.

Most young athletes who want to continue playing sports, especially basketball, soccer, volleyball, football and wrestling, choose to undergo ACL reconstruction surgery. Without surgery, a person with a torn ACL is at risk for repeated knee instability. Each time the knee gives out, there is a risk of increased damage to the meniscal or surface cartilage in the knee, which is extremely difficult to repair and can cause arthritis later in life.

Because the ACL will not heal even if it is repaired, a nearby tendon is used as a substitute for the torn ACL tendon, which is why the procedure is called a reconstruction. The reconstruction goes through the growth plates of the leg bone (tibia) and the thigh bone (femur), so children and adolescents with substantial growth remaining in their knees are at some risk for a slowing of growth if ACL surgery is performed before they are finished growing. It is often best for children and adolescents who are still in their peak growth spurts to delay ACL reconstruction until they are near skeletal maturity. Slowed growth in the knee can lead to a shorter leg, and even worse, abnormal angulation or displacement in the legs.

The occurrence of growth arrest after ACL reconstruction in young patients is a rare complication. Once an adolescent's ACL is reconstructed, he / she can usually return to his / her prior level of sports competition without any more episodes of instability.

A non-operative treatment program usually consists of aggressive rehabilitation with strengthening of the knee muscles, regaining range of motion and controlling swelling. A brace can be used for support; however, basketball, soccer, wrestling, football and volleyball should probably be avoided by patients awaiting reconstruction.

Caring for the injured knee

In addition to knee swelling and moderate pain, your child probably won't be able to walk on his / her leg initially. Your child's physician or nurse will give you detailed instructions about how to care for your child. Your child may need to walk with crutches, with weight-bearing as tolerated, and may start physical therapy soon after the injury. Your child should also rest and ice the knee, apply compression with an ACE" wrap and knee brace, and use medication for inflammation and pain as instructed.

Preventing an ACL injury

Neuromuscular training (learning how to land properly from jumps) may reduce ACL injuries in females.

When to call the doctor

You should call your child's pediatrician, family doctor or orthopaedic doctor for severe pain that continues despite pain medication. The doctor should also be contacted if your child develops pain, numbness or coldness in his / her leg, or if his / her knee keeps giving out.