Anterior Cruciate Ligament (ACL) Injury: Repair & Reconstruction
Whether you’re seeking to expand your knowledge about anterior cruciate ligament (ACL) injuries or currently grappling with one, this article is designed to provide a thorough, evidence-based understanding of ACL injuries. We’re committed to offering guidance and preventing future deterioration of the knee joint.
Understanding the ACL
The stability and flexibility of our knees rely on the vital role played by the ACL, or anterior cruciate ligament. Acting as a guide, it enables the shin bone (tibia) to smoothly navigate its range of motion during dynamic activities such as kicking, pivoting, and weaving. Comprised of durable collagen strands, the ACL, about the thickness of an index finger, exhibits remarkable strength, capable of withstanding forces up to 500 pounds. Unfortunately, an ACL injury can hinder its performance, leaving the knee joint weakened and prone to additional harm.
What is a Ruptured ACL Injury?
A ruptured ACL injury refers to a tear in the ligament, often resulting from sudden changes in direction, falling awkwardly, or decelerating rapidly from a run. When the ligament tears, it unravels like a rope and cannot heal without intervention. With the ACL injured, the knee often becomes unstable and may buckle during attempts to stop or turn.
How Does an ACL Become Ruptured?
ACL injuries can happen in different ways, and athletes and sports enthusiasts are especially prone to them due to the intense strain they put on their joints and ligaments. Sudden changes in direction, particularly when the foot is firmly planted on the ground, can result in ligament tears and ACL injuries. Contact sports like rugby or American football also pose a risk, as the knee can be struck from the front, leading to injury.
How Common is an ACL Injury?
ACL injuries are the most common knee injury, accounting for around 40% of all sports-related injuries. Therefore, in that context, ACL injuries are relatively common. Those who are physically active are more at risk, but it’s worth noting that ACL injuries are less likely unless you regularly participate in sporting activities.
Symptoms of an ACL Injury
Patients often describe hearing a loud pop followed by pain in the affected knee. This pain can make walking or bearing weight on the knee difficult. After a few hours, the knee begins to swell due to bleeding in the joint. This swelling, while protecting from further damage, can make it harder to straighten the knee.
Diagnosing an ACL Injury
Diagnosing an ACL injury involves a physical examination, during which an orthopaedic surgeon will take your medical history, examine your knee for range of motion, stability, tenderness, and swelling, and may order X-rays to check for any fractures. In many cases, an MRI of the knee may also be prescribed to provide more information if the history and examination are inconclusive regarding an ACL tear.
For a case study on an ACL injury - click here
Treatment Options for an ACL Injury
Treatment options for an ACL injury depend on several factors, including the patient’s symptoms, examination results, remaining growth in the growth plates, type of ligament injury, and the patient’s sports and activity goals. Non-surgical treatment, including immobilisation or bracing, physiotherapy, and a gradual return to regular activities and sports, is most appropriate for grade 1 injuries. Surgical treatment is recommended for individuals with a grade 3 or complete ACL tear.
Surgical Treatment
Surgery typically occurs several weeks after the injury, usually within 5 months, to allow swelling to recede, enable pre-surgery rehabilitation to strengthen the muscles surrounding the knee, and reduce the risk of excess scar tissue. There are three main options for the reconstruction of a torn ACL, each involving grafts from different sources:
Kneecap Tendon Repair: The middle portion of the patella tendon can be used to create a new ligament. This new ligament, called a patella graft, provides a secure graft. A disadvantage of this method is post-surgery knee pain, which can sometimes last up to 2 years.
Donor Repair: Similar to the above, a patella tendon is taken from a deceased donor. This method results in less post-surgery pain but is not as reliable as using the patient’s patella tendon because the sterilisation process kills the living cells in the graft, meaning it takes longer to heal.
Hamstring Repair: A portion of the tendon is removed from the hamstring, a large, strong muscle group located at the back of the thigh, and used to make a new ACL. The hamstring is very resilient and returns to full strength within just 6 months.
Regardless of the chosen treatment method, rest, painkillers, and ice packs are important aspects of managing an ACL injury. Rehabilitation is a crucial part of recovery, involving exercises to strengthen the muscles around the knee and improve joint motion.
Prevention of ACL Injuries
Using appropriate techniques when exercising or playing sports can help prevent ACL injuries. Some college sports programmes teach athletes how to reduce stress placed on the ACL, involving a series of warm-up exercises and jumping drills. It’s debatable whether wearing knee braces during strenuous sports activity helps prevent knee injury.
Rehabilitation Stages for ACL Injuries
Rehabilitation following an ACL injury typically involves three stages, each designed to gradually restore strength and mobility to the knee. These stages are tailored to the individual’s progress and specific needs.
Stage 1: This stage focuses on reducing knee swelling, restoring range of motion, and maintaining muscle control.
Stage 2: The second stage involves improving strength, balance, and muscle control further, while gradually reintroducing more demanding activities.
Stage 3: The final stage is about returning to normal function and includes sport-specific exercises.
If you’d like additional information about ACL injuries or to discuss how we may be able to assist you with your rehabilitation, please contact us. We’re eager to help you understand and manage your ACL injury, preventing future knee joint deterioration and ensuring a successful recovery.