Types of ACL Injuries - Topic Overview
anterior cruciate ligament (ACL) injury often is
called a sprain. A sprain occurs when the threads or fibers of the
ligament stretch or are torn. Most ACL injuries occur
in the middle of the ligament.
See an illustration of the
knee and the ACL .
An ACL injury is classified as a grade I, II, or III sprain.
Grade I sprain
- The fibers of the ligament are stretched, but
there is no tear.
- There is a little tenderness and
- The knee does not feel unstable or give out during
Grade II sprain
- The fibers of the ligament are partially
- There is a little tenderness and moderate
- The joint may feel unstable or give out during
Grade III sprain
- The fibers of the ligament are completely torn
(ruptured); the ligament itself has torn completely into two parts.
- There is tenderness (but not a lot of pain, especially when
compared to the seriousness of the injury). There may be a little swelling or a
lot of swelling.
- The ligament cannot control knee movements. The
knee feels unstable or gives out at certain times.
An ACL avulsion occurs when the ACL is torn away from either the
upper leg bone or lower leg bone. This type of injury is more common in
children than adults.
An avulsion fracture occurs when the ACL is torn away from the leg
bone with a piece of the bone.
WebMD Medical Reference from Healthwise
May 14, 2010
This information is not intended to replace the advice of a doctor.
Healthwise disclaims any liability for the decisions you make based on this
© 1995-2013 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Types of ACL Injuries Topics