Anterior Cruciate Ligament (ACL) Tear Symptoms & Treatment

The anterior cruciate ligament (ACL) is one of the four major ligaments in the knee. It runs through the middle of the knee and connects the thigh to the shin, stabilizing the knee joint. It provides the primary restraint to the femur (thigh bone) moving on the tibia (shin bone). It also provides stability by helping to control excessive rotation of the knee and preventing knee instability. 

Anterior cruciate ligament tears, or ACL injuries, are among the most common sports knee injuries, especially in athletes who engage in activities that require quick direction changes or jumping. These injuries frequently occur without direct contact, making them a common non-contact knee injury.

This ligament can tear, either partially or completely, due to injury.

Most ACL injuries are non-contact knee injuries, which happen when there is no physical contact between players. However, in some cases, an impact such as a side tackle in football may cause a torn ligament. Women are statistically more likely to suffer from ACL injuries than men due to anatomical and hormonal factors.

A tear of the anterior cruciate ligament (ACL) usually occurs from hyperextension (over-straightening) of the knee. In addition, the ACL can tear as a result of the following movements:

• A sudden stop
• Twisting of the knee
• A pivot or sudden change in direction, which is common in basketball
• Jumping and landing awkwardly on one foot, for example, after jumping to hit a volleyball

In some instances, direct impact, such as a sliding tackle in soccer, can also result in an ACL injury.

Direct impact, like from a sliding tackle in soccer, can also cause an ACL tear.

ACL tears are common in these sports:

• Basketball
• Football
• Gymnastics
• Lacrosse
• Volleyball
• Skiing
• Rugby
• Snowboarding
• Soccer
• Softball
• Wrestling

You may have an ACL tear if you experience one or more of the following symptoms after an injury to the knee:

• Immediate swelling after injury
• A popping sensation or pain on the outside of the knee
• Feeling that the knee is unstable or that it “gives out”

ACL tears are associated with injuries to other structures of the knee, including:

• Medial collateral ligament (MCL) tear
• Lateral collateral ligament (LCL) tear
• Meniscus tear of the medial or lateral meniscus

You will most likely experience symptoms immediately following a torn ligament in the knee. If you’ve sustained a sports knee injury and are experiencing swelling, pain and feelings of instability, visit an orthopedic specialist as soon as possible.

Your doctor will evaluate your knee for swelling, stiffness, range of motion, and instability. Diagnostic tests like the Lachman or anterior drawer test assess the integrity of the anterior cruciate ligament. A loose or unstable feeling may suggest an ACL tear.

[IMAGE of Lachman Test]

In order to make a diagnosis, your doctor may prescribe the following imaging tests:

• X-ray to assess the bones of the knee and to rule out a fracture
• MRI to make a diagnosis and look for other problems in the knee

If you have an ACL tear, your initial treatment steps will focus on reducing swelling and regaining mobility of the knee. This will be achieved using treatments like:

• Resting the knee
• Icing the knee throughout the day
• Using a brace to stabilize the knee
• Physical therapy to regain mobility

If you play a sport that does not require a lot of demand on the knee, or if you have a partial tear and your knee is still stable, you may be able to use more conservative, non-operative treatments. Non-operative treatments used to treat an ACL tear include:

• Physical therapy to reduce swelling, strengthen the muscles around the knee, and regain mobility
• Using a specially designed brace that stabilizes the knee

Try these exercises to help address your condition:

Below is a PDF of the Exercise Program

Knee ACL Injury

If you play a sport that demands a lot from your knee, and your ACL is torn completely, you most likely want to consider surgery to reconstruct the ligament. This is because a torn ACL causes chronic instability of the knee and can cause significant secondary damage to other structures of the knee, including other knee ligaments, the joint surfaces, and/or the meniscus.

The goal of surgical treatment of an ACL tear is to replace and reconstruct the damaged portion of the ACL in order to restore stability to the knee. During ACL reconstruction surgery, the ligament is reconstructed using a piece of tendon from somewhere else in your body, or from a donor, called an allograft. Three types of grafts are commonly used:

Allograft

An allograft is a graft obtained from a cadaver to reconstruct the ACL. This technique usually allows for quicker initial recovery time, less pain, and smaller incisions, as the graft is not obtained from you.

Bone-Patellar Tendon-Bone Graft

The patellar tendon can be used to reconstruct the ACL. During this procedure, the middle third portion of the patellar tendon (the ligament that attaches the kneecap to the shinbone) with a piece of bone on either end is removed and used to replace the ACL. This technique has the advantage of using the bone end for more secure initial attachment. Its disadvantages are slightly more pain in the immediate postoperative period, a larger incision, and a slightly higher incidence of kneecap symptoms after the operation.

Hamstring Graft

Another common graft used for ACL reconstructions is the hamstring tendon, which is harvested close to the knee on the inner side of the leg. This technique has the advantage of using a smaller incision with less pain postoperatively and less kneecap pain. The graft may take longer to heal than the patellar tendon graft, as it relies on soft tissue healing to the bone rather than bone-bone healing.

ACL reconstruction surgery is performed using both arthroscopic and open techniques. Arthroscopic surgery uses several tiny incisions to access the knee. Through one of these incisions, a tiny camera attached to the end of a thin, flexible tube is inserted. Special instruments used to perform the reconstruction are inserted through the other small incisions. One larger incision is usually needed to harvest the graft and perform the remainder of the surgery.

Before you can have an ACL reconstruction procedure, you’ll need to regain your motion.
This can be done on your own (see exercises below) or with the help of a skilled physical therapist.This may take several weeks but is crucial to the success of your procedure.

Recovering from ACL surgery is a long process. It’s important to have patience throughout this process and to follow all instructions given to you by your orthopedic surgeon and licensed physical therapist. Your involvement in the rehabilitation process is crucial to your success, and in getting back to your athletic career.

Throughout the first two weeks following surgery, you will need to ice your knee to reduce swelling. You will also be given exercises by your doctor to work on straightening the knee in addition to contracting or controlling the quadriceps muscles. Your doctor may give you a machine that bends and straightens your knee to be used for a certain number of hours each day. When directed by your orthopedic specialist, you will begin exercises with your physical therapist aimed at helping you regain balance and control of the injured leg. You will be directed to do exercises at home every day.

While your physician and therapist will individualize your program, all rehabilitation protocols are designed to protect the graft while it is healing and to help you slowly and carefully regain your range of motion and strength. Exercises are added gradually and, when there is enough strength and stability regained, running and later cutting exercises, called plyometrics, are added.

Complete rehabilitation following ACL surgery can take six to 12 months. You can return to normal activities when you have no swelling or pain, and you have regained full range of motion, strength, stability, and function of the knee.

[BUTTON: See Example ACL Rehabilitation Program]