Anterior Cruciate Ligament (ACL) Injury

What Is an ACL Injury?

An ACL injury refers to a tear or sprain of the anterior cruciate ligament, one of the key ligaments that helps stabilize the knee joint. This ligament connects the thighbone (femur) to the shinbone (tibia) and is crucial for controlling forward and rotational movement of the knee.

ACL injuries are common in sports and activities that involve sudden stops, changes in direction, or high-impact landings. Depending on the severity, ACL injuries can range from a mild sprain to a complete ligament tear, often affecting mobility and requiring targeted treatment.

What Are the Types of ACL Injury?

ACL injuries are classified based on their severity and nature:

What Causes an ACL Injury?

ACL injuries occur when the ligament is stretched beyond its normal capacity. The most common causes include:

1. Sudden Changes in Direction: Pivoting or cutting sharply while running can place excessive strain on the ACL.
2. Improper Landings: Jumping and landing incorrectly, with an inward knee bend, increases risk.
3. Direct Trauma: Collisions, such as those in contact sports, may result in a forceful knee twist or hyperextension.
4. Overuse: Repetitive movements, particularly in sports like basketball or soccer, may weaken the ligament over time.
5. Biomechanical Issues: Poor form, muscular imbalances, or improper footwear may predispose individuals to ACL injuries.

Signs and Symptoms of an ACL Injury

Individuals with an ACL injury often experience the following:

• Popping Sound: Many report hearing or feeling a "pop" at the time of injury.
• Immediate Pain: Severe pain, especially upon trying to put weight on the affected leg, is common.
• Rapid Swelling: The knee typically swells within hours due to internal bleeding in the joint.
• Instability: The knee may feel unstable or give out, particularly during weight-bearing activities.
• Loss of Range of Motion: Stiffness and difficulty fully straightening or bending the knee are frequent complaints.

How Is an ACL Injury Diagnosed?

Proper diagnosis allows the orthopaedic doctor to determine the best treatment plan. This process involves:

How Is an ACL Injury Treated?

Treatment options depend on the injury's severity, the patient’s activity level, and their long-term goals. Generally, treatments fall into non-surgical and surgical categories.

Non-Surgical Treatments

Non-surgical methods are often effective for partial tears or individuals with low physical activity demands. These include:

1. Rest, Ice, Compression, and Elevation (RICE): Helps to alleviate pain and swelling.
2. Physiotherapy: A structured rehabilitation programme can strengthen surrounding muscles (quadriceps and hamstrings) to improve knee stability.
3. Bracing: A knee brace may provide additional support during healing and prevent further injury.
4. Medications: Over-the-counter pain relievers can help to manage discomfort and inflammation.

Surgical Treatments (ACL Reconstruction)

Surgery is often recommended for complete ACL tears, recurrent instability, or those who wish to return to high-demand sports. As the torn ligament cannot heal itself, it is replaced using a graft, which may come from the patient’s hamstring, patellar tendon, or a donor. The procedure is minimally invasive, and arthroscopy is often used to repair the ligament.

Can an ACL Injury Be Prevented?

While not all ACL injuries are avoidable, the risk can be reduced with some of these preventative measures:

1. Strength Training: Be sure to strengthen the muscles around the knee, particularly the quadriceps and hamstrings, for improved joint stability.
2. Neuromuscular Training: Embark on exercises that enhance balance, coordination, and proper movement mechanics.
3. Stretching and Warm-Ups: Adequate stretching before activities ensures that the muscles are flexible and reduces strain on the ACL.
4. Practice Proper Techniques: Learn safe landing techniques and form for cutting or pivoting motions.
5. Wear Appropriate Footwear: Shoes that provide adequate support and grip can help reduce stress.
6. Avoid Overtraining: Allow for rest and recovery to minimize the risk of repetitive stress injuries.
7. Use Protective Gear: In contact sports, wear proper braces or supports to reduce the likelihood of knee injuries.

Frequently Asked Questions