anterior cruciate ligament (ACL) can be injured if the knee is straightened
beyond its normal limits (hyperextended), twisted, or bent side to side. ACL
injuries may include tears of the ligament, a complete rupture of the ligament,
or a separation of the ligament from the upper or lower leg bone (avulsion).
Injuries to the bone, other knee ligaments, or a cartilage (meniscus) often occur at the same time as ACL
Symptoms of a severe and sudden (acute) ACL injury include:
Feeling or hearing a pop in the knee at the time
Pain that may be mild or severe.
feeling of instability in the knee after a jump, change in direction, or after
a direct blow to the side of the knee.
Knee swelling within 1 to 2
hours of an injury.
Swelling that is severe enough to limit
Symptoms of a chronic ACL injury include a feeling of instability and
sometimes pain and swelling.
Treatment for ACL injuries will depend on the severity of the knee
injury and your activity level. The goal of treatment is to stabilize the knee
and prevent further damage to the knee. Treatment includes rehabilitation
exercises and possibly surgery.
Primary Medical Reviewer
William H. Blahd, Jr., MD, FACEP - Emergency Medicine
How this information was developed to help you make better health decisions.