ACL Injury

What is an ACL Injury?

The anterior cruciate ligament (ACL) is one of four major ligaments that help stabilize the knee. A sprain or tear of this ligament is common during sports participation. An ACL injury typically occurs when the foot is planted and the knee gets bent backward, is twisted or bent side-to-side, especially if more than one of these movements occurs simultaneously.

Baptist Health is known for advanced, superior care for patients with orthopedic conditions and the diagnosis, treatment and management of ACL injury. You will appreciate timely appointments and a professional, friendly atmosphere where we take time to listen to your concerns. At Baptist Health, you have access to the region’s most comprehensive, multidisciplinary team of specialists and innovative therapies, including many available only through specialized clinical trials. In every way, we work to demonstrate the utmost in excellent care to those who trust us with their health.

Signs and Symptoms

Torn ACL symptoms can include:

  • A loud “pop” sound as the ligament tears
  • Pain on the outside and back of the knee 
  • Swelling that begins within a few hours of the injury
  • Loss of range of motion in the knee
  • Difficulty/discomfort when walking 
  • Being unable to put weight on the knee or the sensation that the knee is “giving out” 

ACL Injury Diagnosis

If ACL injury is suspected, we perform a physical examination and ask questions about symptoms. Structures of your non-injured knee will be compared to the structures of your injured knee. Most ligament injuries can be diagnosed by thorough physical examination. However, we may use advanced diagnostic procedures and technology to effectively diagnose, inform treatment and carefully monitor the condition. Common diagnostic procedures can include:

X-rays: While X-rays will not show any injury to your anterior cruciate ligament, X-rays can show whether the injury is associated with a broken bone.

Magnetic Resonance Imaging (MRI): A large magnet, radio waves and a computer are used to produce pictures of the knee. This creates better pictures of soft tissues (like the ACL); however, an MRI is usually not required to make the diagnosis of a torn ACL.

Arthrography: During this test, a contrast iodine solution is injected into the knee to help highlight the joint structures, such as the ligaments, cartilage, tendons and joint capsule. Several X-rays of the joint are taken, using a fluoroscope, a special piece of X-ray equipment that immediately shows the image. 

What Causes a Torn ACL?

Preventable causes of ACL injury can include:

  • Stopping suddenly or changing direction quickly while the foot is firmly planted and the leg is hyperextended (straight)
  • Physical collision with a stable object 

Risk Factors

Risk factors that can contribute to ACL injury include:

Gender: ACL injury is most prevalent in men because of greater participation in sports. Women are at higher risk of ACL injury among athletes, possibly because of anatomy differences which may increase the possibility of movement that can overextend and injure the ACL. 

Previous ACL injury: Once an ACL tear has occurred, the risk of a re-tear is 15 percent higher.

Age: The most common age for an ACL injury is between 15 and 45 years, probably due to the higher level of activity and sports participation during these years.


While many risk factors cannot be controlled, you can help prevent ACL injury in these ways:

Proper physical training: Training to strengthen muscles of the legs, hips and lower torso, as well as training to improve jumping and landing techniques, may reduce ACL injury risk.

Proper muscle conditioning: Stretching and strengthening the leg muscles, especially the front and back muscles of the thigh (quadriceps and hamstrings), as well as thorough warm up and cool down both pre-and post-work out, can reduce ACL injury. 

Proper footwear: Don’t wear cleats during contact sports and avoid wearing high-heeled shoes.

Avoid certain sports: Risk of an ACL injury increases in sports requiring lots of quick direction changes (soccer and basketball) and physical contact (football and hockey).

Maintain a healthy weight: Excess body weight increases pressure on all the joints, including the knee.

Avoid activity during slippery conditions: A slick surface increases the chance of slipping and falling awkwardly, increasing the risk of harmful twisting or bending of the knee.

ACL Prognosis

The prognosis for people with ACL injury depends upon the severity of the injury, which can run the spectrum from mild sprain to a torn ligament that requires surgery. Most people who have surgical reconstruction of the ACL have a good outcome and are usually able to return to many of their previous activities within six to nine months after surgery.

Treatment and Recovery

The main treatments for ACL injury are:

PRICE Protocol

First, immobilize the leg (splint, brace, crutches) to Protect it from further injury. Next, Rest the knee, put Ice on it, apply gentle Compression to the knee using an elastic bandage and Elevate the leg by propping it up above the level of the heart for 24 to 48 hours. 


Take over-the-counter pain and inflammation reducer, such as ibuprofen.

Rehabilitation Therapy

Following doctor’s orders, rehabilitation may include any of the following: physical therapy, occupational therapy, massage therapy, kinesio-taping (provides support and stability without restricting motion), acupuncture and osteopathic manipulation.

What is ACL Surgery?

Most ACL tears cannot be sutured (stitched) back together. Thus the ligament must be reconstructed through ACL reconstruction surgery. The doctor may replace a torn ligament with a tissue graft that acts as a scaffolding for a new ligament to grow on.

Types of ACL Surgery—There are two main types of ACL Surgeries and two main graft options:

  • The most common type is an ACL reconstruction.
  • In rare cases, you might be able to receive ACL repair.
  • Your doctor will either perform an autograft or allograft.
  • An autograft is grafting with another part of your body. One example is called a patellar tendon graft.
  • An allograft is grafting from a donated medical cadaver.

How Long it Takes—ACL surgery can last anywhere from one to three hours. Typically, ACL surgery is an outpatient surgery where you can return home the same day.

Recovery—After ACL surgery, you can expect your recovery time to last for six months or more. Your ACL recovery time will vary based on the type of surgery you undergo. The rehabilitation process can take up to two years for an ACL reconstruction with graft and six months for one without grafts. Your doctor will inform you what to expect with your ACL surgery scar and ACL brace after surgery.


Complications of ACL injury may include:

Reduced knee function: A completely torn ACL will probably never heal back to it pre-injury “normal” state even after nonsurgical treatment such as rehabilitation and physical therapy.

Further knee injury: Half of all ACL injuries include damage to other knee structures, such as articular cartilage, meniscus or other ligaments.

Arthritis: The risk of developing arthritis in the injured knee varies depending on the severity of the ACL tear, whether there is additional damage to the knee joint, or the level of activity after the ACL treatment.

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