Anterior Cruciate Ligament (ACL) Injury & Tear

A common knee injury, especially among athletes participating in sports like basketball, football and soccer is an anterior cruciate ligament (ACL) sprain or tear. The ACL is one of the two main ligaments in the knee and runs diagonally through the middle of the knee. The main purpose of the ACL is to give stability when the joint is rotating, such as when we make quick turns and keep the tibia and femur in correct relation. About half the time, an ACL injury occurs concurrently with another ligament or cartilage /meniscus injury. Most commonly, ACL reconstruction surgery is the treatment of choice for a serious injury.

Causes of ACL Injury

As mentioned above, ACL injuries happen most often when playing sports, especially those that require rapid changes in direction or contact. Stopping suddenly or landing poorly from a jump can injure the ACL as well. Females tend to be more prone to ACL injury in certain sports than males. Sports that commonly cause an ACL injury include soccer, football, baseball, basketball and tennis.

Types of ACL injury

Injuries to the ACL are known as sprains and have varying levels of severity. A grade 1 sprain involves the stretching of the ACL, but its stabilizing capability is retained. Grade 2 involves an injury where the ligament is stretched far enough that the joint becomes loose. This can also be referred to as a partial tear. A grade 3 strain involves a complete tear of the ligament and the joint is now unstable.

Symptoms and Signs of ACL Injury

The most common sign of an ACL injury is a popping sound, weakness and significant pain in the knee while playing sports. This instability will not abate even if the initial swelling does. Most ACL tears will be painful and uncomfortable, and many patients will not have their full range of motion. As a result, it is important to have it evaluated soon after the injury. While ACL tears are common, dislocation, fracture, meniscus/cartilage injury or other ligament injuries may also share some of the symptoms of an ACL tear.

Diagnosing an ACL Injury

The majority of ACL injuries can be diagnosed with a thorough physical examination and medical history. Your doctor will ask how the injury was sustained and do some physical test on the knee to check structures, stability and areas that may be painful. On occasion, x-rays and MRIs may be performed to confirm the diagnosis and check for other related or co-occurring injuries. This is especially true if no weight can be placed on the knee due to pain. An x-ray and MRI may be used to diagnose or rule out a fracture or dislocation.

When is Surgery Indicated?

For grade 1 sprains, nonsurgical treatment may be sufficient to allow the patient to return to normal daily activity. Rest Ice, Compression and Elevation along with anti-inflammatory medication prescribed by your doctor will likely be the first course of action. Bracing and physical therapy may be required to help the injury along.

However, if the patient wishes to return to sports or if the ACL is torn, surgery is necessary for a complete recovery. With that said, age is a consideration for surgery. Older patients who will return to a less active lifestyle may not need surgery and a brace with physical therapy may be sufficient to maintain the stability of the joint. This will be determined on a case-by-case basis.

ACL surgery

The ACL has limited capacity to heal itself, making it very difficult to repair. An ACL repair procedure may be considered in certain circumstances, but most often a reconstruction offers the best long-term results and a lower chance of failure. Reconstruction involves using other tissue. This can be harvested either from the patient’s body or from a donor – called autograph or allograft tissue, respectively. During surgery, the ACL is rebuilt using this new tissue to allow the ligament to regrow in similar manner prior to the tear.

Learn more about ACL reconstruction surgery