Arch pain

What is an ACL injury?

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An anterior cruciate ligament or ACL injury involves a tear in one of the ligaments of the knee that links the upper leg bone with the lower leg bone. Remember that the ACL is responsible for keeping the knee stable.

The injuries range from minor such as a small-sized tear or severe such as a full tear to the ligament or if the ligament and bone fragment separate from the rest of the bone.

Possible causes of an ACL injury

An ACL injury often develops while playing sports. The injury can occur if the foot is planted firmly on the ground and an abrupt force strikes the knee while the leg is in a straight or slightly bent position.

This can occur while changing directions rapidly, slowing down while running or landing from a jump. The injury is quite prevalent in skiing, soccer, football or other sports that involves stop-and-go motions, weaving or jumping.

ACL injury
This can occur while changing directions rapidly, slowing down while running or landing from a jump.

Falling out of a ladder or missing a step on a staircase are also possible causes. Similar with other parts of the body, the ACL weakens with age. With this in mind, a tear can easily occur among individuals aged over 40 years old.

What are the indications?

The signs and symptoms of an acute ACL injury include the following:

  • Feeling or hearing popping in the knee at the time of injury.
  • Pain on the exterior and back part of the knee.
  • The knee is swollen during the initial hours of the injury. This might be an indication of bleeding within the joint. Swelling that occurs abruptly is usually an indication of a serious injury to the knee.
  • Joint feels unstable, buckling or about to give out.
  • Limited movement of the knee due to the swelling or pain or both.

After sustaining an acute injury, the individual has to stop any activity due to the pain, but might still be able to walk.


An individual with an ACL injury should be given first aid care right away. The first aid measures are aimed on reducing the pain and swelling.

You have to utilize the RICE method which includes rest, application of ice, compression using an elastic bandage and elevate the affected limb above the level of the heart. At first, it is vital to move the leg as minimal as possible and provide an over-the-counter pain medication.

Crutches can be used to assist with walking and a knee immobilizer to keep the knee immobile during the initial few days after the injury. The knee should be checked by the doctor. It is important to seek treatment because if it is delayed, the injury can become a lasting issue.

Quick Note / Disclaimer

The material posted on this page on ACL injury is for learning and educational purposes only. To learn to recognize and manage muscle injuries including ACL injury , register for a first aid and CPR course with Victoria First Aid.

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