Anterior Cruciate Ligament (ACL) Injury: Tears, Ruptures & Sprains

ACL injury at a glance

  • The ACL is one of the ligaments connecting the thighbone (femur) with the shinbone (tibia) inside the knee joint.
  • During an ACL injury, the ligament may be torn, ruptured, or separated from the bone.
  • ACL injuries frequently occur during sports or work activities, when the knee is bent backwards, twisted, or hit with force.
  • Symptoms of an ACL injury include pain and swelling on the outside and back of the knee, and instability or limited movement in the knee joint. A loud popping sound is often heard at the time of injury if the ACL tears or ruptures.
  • Treatment for an ACL injury initially includes rest, ice, elevation, and compressing the knee with elastic bandages. Pain medication that reduces swelling, such as ibuprofen, may help reduce the symptoms. Talk to your pharmacist before purchasing anti-inflammatories as these medications may be contraindicated as they may interact with other medications and medical conditions.
  • Physical therapy exercises, rehabilitation, and/or surgery may be necessary for some ACL injuries.

Causes of ACL tears

ACL injuries are one of the most common injuries seen in sports medicine. ACL tears, sprains or ruptures most often caused by sports that require quick changes of direction, jumping or pivoting, such as soccer, basketball, tennis, and skiing. Contact sports like football can also cause ACL injuries, when the knee is hit with direct force.

It is possible to injure the ACL during everyday activities as well. Falling off a ladder or skipping a step when walking up or down stairs can cause the ligament to tear. Since ligaments weaken with age, people over age 40 are more likely to experience ACL tears during normal activities.

Symptoms of ACL tear or rupture

During an ACL injury, primarily with an ACL tear or rupture, you may hear or feel a loud pop in the knee. Other symptoms include intense pain, swelling, and difficulty moving the joint. The pain is typically felt most in the back or outside of the knee.

While it may be possible to walk, the affected knee may feel unstable, as if it might give out during use.

Treatment for ACL tear or sprain

At the time of the injury, the knee should immediately be treated with the RICE protocol: Rest, Ice, Compression (with an elastic bandage) and Elevation of the knee above the level of the heart. Non-steroidal anti-inflammatory medication (such as Advil or Aleve) may help reduce the pain and swelling.

An ACL tear is a serious injury that should be evaluated by a physician or orthopedist. Physical therapy will be necessary to rehabilitate the injured knee. Rehabilitation will include exercises that stretch and strengthen the knee and surrounding muscles. It may be necessary to immobilize the knee with a brace, and/or to use crutches.

Surgical options for reconstructing ACL

For patients who wish to return to a high level of physical activity, ACL reconstruction surgery may be necessary. Because it is not possible to repair the torn ligament, a piece of tendon from the patient’s leg will be used to reconstruct the ACL.

Several months of rehabilitation will be necessary following the reconstructive surgery.

If you have recently experienced an ACL injury, contact us the schedule an appointment with our knee specialists in the San Francisco Bay Area to begin your road to recovery.