I’m willing to place a friendly wager that somewhere throughout your life you’ve heard a reference to this infamous bodily structure: THE ACL!
Whether you’re an avid sports fanatic that has witnessed your favorite athlete suffer this horrible injury. Or maybe you’re just a weekend warrior that occasionally watches the sport news.
Regardless of whether you’ve had personal experience with this fickle bodily structure or not.
The anterior cruciate ligament, more commonly known as the ACL, remains one of the most infamous connective tissue structures in the human body.
What is the ACL?
The anterior cruciate ligament is first and foremost a connective tissue. It originates from the posterior femur and attaches onto the anterior horn of the medial meniscus as well as the superior area of the tibia.
Now that may sound extremely clinical, but all you need to know is that the ACL is a ligament within the knee capsule that attaches to both the thigh and shin bone.
It’s specific attachment and shape is vital for its primary functions.
What is the Function of the ACL?
The anterior cruciate ligament is connective tissue found within the knee capsule. It’s main purpose from a functional standpoint, is to prevent anterior translation of the tibia (shin bone). Now in layman’s terms all that essentially means is that the ACL stops your lower leg from popping out from underneath your thigh bone (femur).
The anterior cruciate ligament provides stability at the knee joint during multiple planes of movement.
However, the primary function the ACL provides is to control the back and forth movement of the joint. As well as providing rotational stability during rapid changes of direction.
This makes the ACL one of the most important pieces of tissues in our body with regards to mobility.
But this is also it’s downfall unfortunately. Because the ACL plays such a vital role in movement, therefore it’s quite often injured.
ACL Injuries
An anterior cruciate ligament injury may range from light bruising. To a moderate or more severe injury that might require surgery.
The most common injury is a ligament sprain or a ligament tear depending on who you ask to define these injuries. This is because some doctors and or therapists define each injury differently. Some call ACL injuries tears while some call them sprains and the rest just use these terms interchangeably.
In a nutshell, all ACL tears are sprains but not all ACL sprains are tears.
Now let’s categorize ACL injuries according to their pathology and severity:
A first grade sprain or light sprain is classified as a slight damage within the ligament fibres, but the entire ligament remains intact. Symptoms of a grade one sprain include pain, swelling and some instability.
A second grade ACL sprain is classified as moderate tearing of the ligament fibres but the integrity of the ligament remains intact. Symptoms are more severe than compared to a grade one sprain, and might even include a “pop” sound at the time of injury.
A third grade ACL injury is when things become serious. The ligament would have partially or completely ruptured. Severe pain, swelling and major instability of the knee joint are all characteristic of a grade three ACL tear.
How do ACL Injuries Occur?
Now the average length of the ACL is 32mm and the width varies 7-12mm. Emphasis on the term “varies” as the difference in width of a particular ACL will determine the vulnerability of the ligament. This means that your individual biological make up or genetics may predispose you to certain injuries. Simply put, the less width the higher the risk of injury.
And many examples of this is quite evident in the sports world. Think of that one player that’s always injured? Or had his career cut short due to multiple recurring knee injuries? Chances are he or she didn’t hit the genetic lotto. It’s unfortunate, we know.
ACL plays an active role during dynamic movements. This makes it vulnerable to both internal and external forces.
More often than not these forces cause the knee joint to buckle, resulting in trauma within the knee capsule. Multiple factors can influence the extent of the trauma such as body posture at the time of injury, the level of force applied at the knee and previous history of knee joint injuries.
Common actions that may lead to an injury include:
ACL Injury risk factors :
How to Confirm an ACL injury
Physical therapists, trainers and doctors may use special tests to confirm whether a patient has suffered an ACL injury.
These tests include Lachman’s clinical test as well as the standard Anterior drawer tests. For both of these tests, you will require a therapist to assist you in the process of confirmation of the injury.
Now it should be stressed that the efficacy of these tests remain far from accurate. Therefore, radiology remains the number one and most accurate diagnostic tool for ACL injuries.
That being said, magnetic resonance imaging remains the gold standard. However, MRI’S are very expensive and not always accessible to all people.
Therefore, for light to moderate ACL injuries, the combination of special tests and physical examination by your physician or therapist should suffice in the process of confirming an ACL injury.
How to Treat an ACL Injury
The immediate treatment of an ACL injury will all depend on the severity of the injury or event. If you suspect a complete rupture or you’ve lost complete control of your knee joint please seek emergency medical care as soon as possible.
However, if your symptoms are moderate and not too severe, RICE (rest, ice, compression and elevation) is the best option immediately after the injury has occured.
Non-steroidal anti-inflammatory drugs are also a good way to manage the swelling and pain.
The use of a brace or crutches to aid in movement while limiting weight bearing may assist in pain management and long term recovery.
During the acute phase of injury, zero weight bearing and ample rest is of great importance to ensure a successful recovery.
ACL Surgery
This surgery involves either repairing the ligament or a complete reconstruction of the tissue.
The latter, in most cases, makes use of donor graft. A graft is a piece of connective tissue cut from either the patellar or hamstring tendon and used to help strengthen the damaged anterior cruciate ligament.
In terms of the actual surgical procedure, this all depends on the extent of the tissue damage.
An ACL repair is usually repaired by making 3-4 tiny incisions around the knee capsule. This procedure is non as an arthroscopy and remains the safer and more efficient surgical option.
Unfortunately, this method isn’t sufficient enough to treat a complete ACL rupture. In these cases an open knee surgery is required. This procedure has far greater risk involved and recovery may take up 2 and half times longer in some cases.
Overall, ACL surgical procedures remain extremely safe and quite successful. The statistics show very little chances of complication after an ACL surgery. So don’t stress about it too much, okay?
And on that note, a surgical intervention is only as good as recovery and rehabilitation protocols. So your commitment to post-operative protocols will be a key role in your recovery.
ACL Recovery
Anterior cruciate injuries have varying recovery time frames. It all depends on the severity of the injury i.e. Grade 1, 2 or 3. And whether any surgical interventions or procedures took place.
We must mention that recovery can be influenced both positively and negatively depending on various circumstances.
The standard prognosis would be physical therapy followed by a return to activity protocol supervised and implemented by a respective therapist. We will touch on this in the second part of this series.
To Summarize…
The anterior cruciate ligament is connective tissue found within the knee capsule. The ACL controls the back and forth movement of the joint. As well as providing rotational stability during rapid changes of direction. ACL injuries range from light to severe and are classified as ACL sprains, tears or complete ruptures. Factors such as weight, age and type of sport or activity may predispose someone to an ACL injury.
Recovery times vary depending on the severity of the injury and might require surgical intervention. ACL injuries will require a stringent recovery and rehabilitation protocol in order for the knee joint to properly function again.