An anterior cruciate ligament (ACL) tear is an injury to one of the four major ligaments of the knee. The ACL is a ropelike structure in the center of the knee that helps maintain the normal relationship between the femur (thigh bone) and tibia (leg bone).
When torn, the ACL does not heal on its own, and the knee can become unstable or give way during activities that require pivoting, changing direction, jumping, or landing. About half of people who tear their ACL also tear a meniscus in the knee.
What Is an ACL Injury?
The anterior cruciate ligament (ACL) is one of the four major ligaments of the knee. It is a ropelike structure in the center of the knee that helps maintain the normal relationship between the femur (thigh bone) and tibia (leg bone).
When the ACL is torn, it does not heal on its own. The knee may become unstable, shifting or giving way during sports and activities that require pivoting, cutting, jumping, or landing.
Causes and Risk Factors
ACL tears may occur from:
- Non-contact injuries, such as landing awkwardly or cutting
- Contact injuries in which the knee sustains a direct hit, such as being tackled at the knee
Risk factors include:
- Sports that require pivoting, jumping, cutting, or changing direction, such as basketball, soccer, and volleyball
- Contact sports such as football and rugby
- Poor physical conditioning, including strength and flexibility
- Female gender
- High friction or traction between the playing surface and shoe
Symptoms
Signs and symptoms of an ACL tear may include:
- A pop or tearing sensation heard or felt at the time of injury
- Inability to continue playing after the injury
- A large amount of knee swelling within six to eight hours after the injury, often within three hours
- Inability to straighten the knee after an injury
- Knee instability, shifting, or giving way, particularly when pivoting, cutting, or jumping
- Swelling with repeated episodes of giving way
- Occasionally, locking of the knee when there is an associated meniscus injury
Treatment
Initial treatment focuses on returning the knee toward its pre-injury condition by reducing pain and swelling and restoring range of motion, strength, and normal walking.
Walking with crutches until you can walk without a limp is often recommended. Range-of-motion, stretching, and strengthening exercises may be performed at home, although referral to a physical therapist or athletic trainer is often recommended. If other ligaments are injured along with the ACL, a brace may be recommended to support the knee.
For patients who do not participate in sports that require frequent pivoting, cutting, jumping, or landing, surgery is not always required and nonoperative rehabilitation may be attempted. Rehabilitation usually focuses on:
- Reducing knee swelling
- Restoring knee range of motion
- Restoring muscle control and strength
- Functional training
- Avoiding higher-risk sports and activities that require pivoting, cutting, changing direction, jumping, and landing
Individuals may be able to continue activities such as jogging, cycling, weightlifting, and swimming without ACL surgery. However, an ACL-deficient knee is at greater risk for progressive meniscus and cartilage damage from abnormal knee mechanics.
For those who participate in sports that require frequent pivoting, cutting, jumping, and landing, surgery to reconstruct the ACL is usually recommended to allow a safe return to these activities. Surgery also is recommended for ACL injuries in young active children and for injuries combined with damage to other ligaments, the meniscus, or articular cartilage.
Nonsteroidal anti-inflammatory medications such as aspirin and ibuprofen, or other minor pain relievers such as acetaminophen, are sometimes recommended as directed by a physician.
Cold can be used to relieve pain and reduce inflammation. It may be applied for 15 to 20 minutes every two to three hours for inflammation and pain and immediately after activities that aggravate symptoms. A cloth should be placed between the ice and skin.
Recovery and Outcomes
The ACL will not heal on its own, but most people can return to normal daily activities after an appropriate rehabilitation program.
Despite returning to normal daily function, an ACL-deficient knee is at risk for progressive meniscus and cartilage damage from abnormal knee mechanics. Recurrent episodes of instability can result in further meniscus injury and damage to the articular cartilage.
For patients who want to return to sports involving pivoting, cutting, jumping, and landing, surgery is usually required.
When to See Dr. Chudik
Contact Dr. Chudik’s office if:
- New, unexplained symptoms develop
- The knee continues to shift or give way and swell
- The knee locks or gets stuck intermittently
Call 630-324-0402, request an appointment online, or email contactus@chudikmd.com.
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