ACL Injury

What is an ACL injury?

An ACL injury is a knee injury that involves the tearing or stretching of the anterior cruciate ligament (ACL), a ligament that stabilises the knee joint. It is a relatively prevalent knee condition, notably affecting athletes, with a higher incidence among females.

High-impact sports and activities marked by abrupt stops, direction changes, jumping, and landing constitute the prime catalysts for ACL injuries. Such demanding pursuits include soccer, basketball, netball, football, and downhill skiing.

ACL injuries encompass a spectrum of severity, with the following categories:

  1. Grade 1 ACL Sprain: The ligament is mildly stretched, resulting in minimal disruption.
  2. Grade 2 ACL Tear: A partial tear of the ligament, leading to moderate instability.
  3. Grade 3 ACL Tear (Complete Tear): The ligament is entirely ruptured, causing significant instability.
  4. Avulsion Fracture: The ACL tears along with a fragment of bone from the tibia. This is a rare injury but most commonly seen in children.
  5. Chronic ACL Tears: Previous ACL tear without any intervention with ongoing instability and joint damage.

While engaging in high-impact sports undoubtedly places the ACL under considerable stress, several key factors contribute to its vulnerability.

  1. Sudden Stops and Direction Changes: Swift, abrupt shifts in motion strain the ACL, especially when combined with forceful stops or changes in direction.
  2. Jumping and Landing Mechanics: Landing from jumps or awkwardly absorbing impact can put undue strain on the ACL.
  3. Poor Conditioning and Muscle Imbalances: Inadequate strength and muscle imbalances around the knee can increase the risk of ACL injuries.
  4. Faulty Movement Patterns: Incorrect techniques during sports or activities can subject the ACL to unnatural stresses.
  5. Inadequate Footwear: Ill-fitting shoes can compromise knee stability, especially during high-impact movements.

Identifying an ACL injury promptly is key to effective treatment. Key symptoms include:

  • A distinct “popping” sensation at the time of injury.
  • Intense pain and swelling in the knee.
  • Limited range of motion, especially difficulty in fully extending or bending the knee.
  • Feeling of instability or giving way, particularly during weight-bearing activities.
  • Swelling and stiffness in the knee joint.

Anatomy Of The Knee

The knee, a complex joint, relies on the interplay of ligaments for stability and fluid movement. At the core of this system lies the anterior cruciate ligament (ACL), a strong band of tissue connecting the femur (thigh bone) to the tibia (shin bone). The ACL is crucial for maintaining knee stability during actions like twisting, turning, and sudden direction changes.

The ACL and the posterior cruciate ligament (PCL) intersect within the knee joint, forming an “X” pattern. While the ACL prevents forward sliding of the shin bone, the PCL guards against backward movement. The PCL is around twice as thick as the ACL, resulting in fewer occurrences of injuries. Complementary to the ACL and PCL, the medial collateral ligament (MCL) and the lateral collateral ligament (LCL) contribute further to overall knee stability.

Treatment & Surgery Options

The appropriate course of treatment for an ACL injury is influenced by its severity and patient demand. For milder cases, a conservative approach often yields positive results. This encompasses a combination of rest and engaging in targeted rehabilitation exercises aimed at regaining strength and stability.

Patients may also be provided with a splint or brace to safeguard the knee from instability or temporarily alleviate weight-bearing stress when more than one ligament is injured or when there is an associated bone injury. While braces initially offer relief from pain and may aid in healing, they are typically phased out to facilitate the reestablishment of normal joint movement. It’s important to note that many of these injuries undergo successful healing without requiring bracing support.

In cases of more severe ACL injuries or patients with high demand activities, surgical intervention through ACL reconstruction may be considered. This procedure involves replacing the torn ACL with a tissue graft, typically utilising a segment of tendon sourced from the same knee. The decision to undergo ACL reconstruction is based on an individual’s activities and the extent of knee instability.

It’s crucial to note that ACL reconstruction is rarely an urgent measure, affording time for thorough preparation. Optimal outcomes are often achieved when operating on a “calm” knee, where swelling and bruising has subsided and good range of motion is restored, promoting smoother postoperative recovery. Prioritising proper knee movement before surgery is paramount for ensuring a successful outcome.

At OSV, we understand the profound impact of ACL injuries on your life. Our team of skilled orthopaedic specialists is committed to devising personalised treatment plans tailored to your unique circumstances, whether you’re an athlete striving to reclaim your sport or an individual seeking to regain everyday mobility.

Contact us today to schedule a consultation and take the first step toward restoring the strength and stability of your knee.

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These notes from OrthoSport Victoria are for educational purposes only and are not to be used as medical advice. Please seek the advice of your specific surgeon or other health care provider with any questions regarding medical conditions and treatment.


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