What Is An Anterior Cruciate Ligament (ACL) Injury?

An ACL tear or sprain is one of the most common knee injuries. ACL injuries are more likely among athletes who compete in high demand sports such as football, soccer or basketball.

About half of all injuries to the ACL occur in addition to damage to other structures in the knee such as articular cartilage, meniscus and other ligaments.

Similar to other parts of the body, injuries to the ligaments are called sprains and are graded on a scale of 1-3 of severity.

The Grades are as follows:

  • Grade 1: The ligament is mildly damaged and it has been slightly stretched, but is still able to help keep the knee joint stable.
  • Grade 2:  The ligament is stretched to the point where it becomes loose. This is often referred to as a partial tear of the ligament.
  • Grade 3: A complete tear in which the ligament has been split into two pieces and the knee joint is unstable.

Partial ACL tears are rare but do occur. Most ACL injuries are complete or nearly complete tears.