ACL Knee Injury

What is ACL Knee Injury

The anterior cruciate ligament, or ACL, is one of four primary ligaments that hold the knee together. Ligaments are tissue that connect and hold bones together to provide stability in the knee. The ACL is located inside the knee joint, running diagonally in the middle of the knee and connecting the bottom of the thigh bone, or femur, to the top of the lower leg bone, or tibia. It is in charge of rotational stability in the knee, but it also prevents the tibia from sliding forward in front of the femur.


The ACL is one of the most injured ligaments in the knee. Many ACL injuries occur in conjunction with damage to other components of the knee joint, like cartilage, meniscus, or other ligament damage. Injury to the ACL happens most often in sports, but it can happen if the knee is hyperextended or forced to twist abnormally, whether from suddenly changing direction or stopping, slowing down while running, incorrectly landing while jumping, or direct contact or collision.

Symptoms and Diagnosis

Symptoms of a torn ACL vary, depending on severity.

Many patients hear a popping noise, followed by the knee "giving." Other symptoms might include painful swelling, impaired mobility and range of motion, and joint tenderness.To diagnose this condition, your doctor will complete a physical exam and review your medical history. X-ray, MRI, and other tests may be done to gauge the severity of the injury in order to determine the best course of treatment.


If the damage to the ACL occurs without making the knee unstable, or if the patient is elderly or has a very low physical activity level, conservative treatment like bracing and physical therapy are attempted first. If the injury is severe and the knee is unstable, this operation will likely be performed.

ACL tears are usually complete or near complete tears, and most of these tears are not able to be repaired. ACL reconstruction is used to replace the ACL with a tissue graft. Only your physician can determine the right treatment for your injury. Rehabilitation is a very important part of recovery from ACL injuries, no matter how severe. After ACL reconstruction surgery, your doctor will prescribe physical therapy exercises. Adherence to these exercises is very important for regaining normal mobility, strength and range of motion. Recovery time varies according to rehabilitation, severity of injury, and other factors.

All information provided on this website is for information purposes only. Please see a healthcare professional for medical advice. If you are seeking this information in an emergency situation, please call 911 and seek emergency help.

All materials copyright © 2024, All Rights Reserved.