Anatomy & Background

Ligaments are tissues made up of fibrous bands of collagen that join a bone to another bone. Stability and limited excess motion are what ligaments provide joints. The knee contains four main ligaments: the medial collateral (MCL), lateral collateral (LCL), anterior cruciate (ACL) and posterior cruciate (PCL) ligaments. Each of these ligaments performs a specific function in creating stability in the knee. If a ligament is injured, both the function and stability of the knee can be drastically reduced.

Anterior Cruciate Ligament (ACL)

The Anterior Cruciate Ligament is an important ligament in the knee because it is one of the primary stabilizers of the knee joint. It is attached to the back of the femur (thigh bone) and runs to the front of the tibia (lower leg). The ACL prevents the tibia from sliding forward on the femur and also limits the rotational movement of the knee.

Anterior Cruciate Ligament Tear

An ACL injury can range from a partial to a complete tear. If the ACL is torn, the stability of the knee is put in jeopardy. The loss of the ACL will result in a sliding forward and twisting movement of the tibia over the femur, which can be extremely painful. This movement can produce increased friction on the meniscus and cartilage in the joint. ACL tears occur more often in women than in men. Adults typically tear the ACL mid-ligament. Tears in children may result in a piece of the leg bone tearing off with the ligament intact where it inserted onto the bone.

Anterior Cruciate Insufficiency

When the ACL is partially or completely torn the stability of the knee may be compromised; also known as an ACL Insufficiency. ACL Insufficiency may also cause excessive sliding forward and twisting movement of the tibia on the femur. This may result in an increased amount of friction on the meniscus and cartilage of the knee. Individuals with an ACL Insufficiency may be more likely to experience meniscus and cartilage damage after the original ACL injury, especially when the individual participates in sports or other activities that involve strenuous movements on the knee joint.

Causes

The ACL can be injured when:

  • The knee experiences a hyperextended (bent backward), side-to-side or twisting motion. This normally occurs when the foot is planted.
  • The knee experiences a high impact blow directly to the joint.
  • A sudden cutting, stopping or twisting motion occurs, or a hard landing from a jump.

Signs and Symptoms

  • Pain and swelling of the knee following the injury can be caused by bleeding following the tear of the ligament.
  • A “pop” in the knee may be heard or felt at the time of the injury.
  • Difficulty walking, with a feeling of the knee “giving out.”
  • Loss of motion when attempting to bend and extend the knee.

Post-Injury Treatment

In response to this type of injury one should initiate the RICE protocol: Rest, Ice, Compression and Elevation, in addition to the following:

  • Rest, by stopping activity immediately.
  • Immobilization of the knee to keep the ligament from enduring more stress.
  • Ice, compression and elevation to reduce inflammation and pain for the first 48-72 hours. Do not apply ice directly to the skin. Only use ice intermittently throughout the day and apply for 20 minutes at a time. Do not apply any form of heat while icing your knee.
  • Contact a pain management specialist for a complete diagnostic evaluation of the injury and to identify the proper plan of care.

Pain Management

After the ACL is injured, you should seek a full evaluation from a pain management specialist or your licensed health care provider. Treatment may consist of the following, depending on the severity of the injury:

  • Clinical evaluation, including a physical exam, X-rays and MRI in more severe Grade III and Grade IV injuries
  • Use of ice and immobilization to help stabilize and rest the joint
  • Anti-inflammatory medication and other pain medications
  • “Progression” an immobilizing device to help stabilize the joint
  • Surgery may be needed for certain ACL tears

The medical treatment of an ACL tear will depend on a number of different variables, which include:

  • Severity, which can be a partial or a complete tear of the ACL ligament
  • Possibility that other structures were affected
  • The patient’s activity level, lifestyle, occupation, etc.
  • Your age is a factor when deciding whether to have a surgical reconstruction

A Conservative Treatment Plan

Following a complete examination of the knee your may recommend a course of physical therapy for the following reasons:

  • Taking into account the individual’s age, activity level, lifestyle, occupation or amount of instability, and pain management, physical therapy may be the best option. This is especially true for a partial ACL tear.
  • If there is a lot of swelling, pain or loss of range of motion it is recommended that the individual seek the opinion of a pain management specialist to improve the condition of the knee in preparation for surgery or to determine if a surgical intervention is necessary.
  • Once the proper diagnosis is made, a plan of care can be developed by the specialist and the patient on how to alleviate the pain permanently.
  • If deemed necessary, the pain management specialist can then provide the necessary intervention for immediate pain relief.