ACL Injuries

| Posted On Jul 07, 2011 | By:

ACL, knee, knee joint, soccer, ligament

The anterior cruciate ligament, or ACL, is one of four major knee ligaments.  Ligaments are strong bands of tissue that connect one bone to another. The ACL connects your thighbone (femur) to your shinbone (tibia) and helps stabilize your knee joint.  The ACL is therefore critical to stability; as a result, people who injure their ACL often complain of symptoms of their knee giving out from under them.  Many patients who sustain an ACL tear opt to have surgical treatment of this injury – although surgery is not always required – and then rehabilitative work to recover effectively.

Potential Causes
An ACL tear is most often a sports-related injury.  About 80% of sports-related ACL tears are “non-contact” injuries.  This means that the injury occurs without the contact of another athlete, such as a tackle in football.  Most often, ACL tears occur when pivoting or landing from a jump. ACL tears can also occur during rough play, collisions, falls, and work-related injuries.

How long does it last?
ACL tears do not necessarily require surgery. There are several important factors to consider before undergoing ACL surgery, such as the level of activity and use of the knee, the severity of the injury, and the degree of knee instability you are experiencing.  If you don’t have an unstable knee and do not plan to perform activities that will place undue strain on the area, then you may not need ACL surgery.

There is also a debate about how to treat a partial ACL tear.  If the ACL is not completely torn, then ACL reconstruction surgery may not be necessary.  Many patients with an ACL tear start to feel better within a couple of weeks of the injury, but a full recovery including physical therapy rehabilitation may take up to 3 months.  Furthermore, even if the knee feels normal again, but problems with instability persist, the knee should be reevaluated.

Home Management
Like many other injuries, one of the best methods to help alleviate discomfort from an ACL injury is The RICE Principle: Rest, Ice (provide adequate skin protection), Compression, and Elevation (above your heart!)

While recovering, you should avoid pivoting on the affected foot, kicking, and jumping.

When should I call my doctor?
The diagnosis of an ACL tear is made by several methods.  ACL tears cause knee swelling and pain. On examination, your doctor will also look for signs of instability. These special tests place stress on the ACL and can detect a torn ligament.  An MRI may also be used to determine if the ligament is torn, and also to look for signs of any associated injuries in the knee.

Preventing ACL tears has been the focus of recent research, especially the prevention of ACL tears in female athletes. Numerous theories have been proposed to explain why people may tear their ACL, and how they can be prevented.

Current investigations have focused on neuromuscular training to prevent ACL tears, particularly the dynamic stabilizers.  The dynamic stabilizers of the knee are the muscles and tendons that surround the joint.  These muscles and tendons are controlled by what’s known as neuromuscular input, the unconscious activation of these structures to control the position of the joint.

Several studies have shown that neuromuscular training programs can reduce the chance of an ACL injury.  One of the better known neuromuscular training programs, the Prevent Injury and Enhance Performance program (commonly known as the PEP program), was developed at the Santa Monica orthopedics and Sports Medicine Research Foundation.

Neuromuscular training can teach your body better habits for knee stability.  By training how your knee moves, especially when jumping, landing, and pivoting, you can maintain a more stable position of the knee joint and hopefully avoid an ACL injury.

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About Celia Repucci

Celia Repucci is a registered physical therapist with the state of Massachusetts. She has worked at Harvard Vanguard Medical Associates at the Chelmsford location since 2008. Prior to joining Harvard Vanguard, Celia worked in a variety of settings including short-term rehabilitation centers and long-term, home and acute care facilities. Most of her prior career was spent in an out-patient private practice working primarily in orthopedics. Celia enjoys working with all ages of patients and the variety of challenges of orthopedic rehabilitation. Prior to becoming a physical therapist, she worked as a professional chef and still enjoys cooking for friends and family.


  1. Thanks for the information Celia! Neuromuscular training programs are indeed effective to prevent ACL injuries especially for professional athletes.

    Comment by Nike Canada on August 30, 2012 at 11:07 am

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