Anterior Cruciate Ligament (ACL) Injury

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Original Editors - Stephanie Geeurickx, Kevin Campion

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Search Strategy

You can search on databases as Pubmed, Web of knowledge and on the database of Vubis. The keywords that were used for this work are: anterior cruciate ligament injury – anterior cruciate ligament injury physical therapy (no surgery) – anterior cruciate ligament treatment – anterior cruciate ligament characteristics – anterior cruciate ligament management. With all these keywords there were found 9 relevant articles used for this work.

Definition/Description

The Anterior Cruciate Ligament is one of the four stabilizing ligaments of the knee. The others are the Posterior Cruciate Ligament, Medial Collateral Ligament and the Lateral Collateral Ligament. The role of the ACL is to prevent forward movement of the Tibia from underneath the Femur. An ACL injury is a torn or a tear of the ligament. It is a relatively common knee injury amongst sports people. A torn ACL usually occurs trough a twisting force being applied to the knee whilst the foot is firmly planted on the ground or upon landing. This means that the Femur is twisting in the opposite direction of the Tibia. A torn ACL can also result from a direct blow to the knee, usually the outside, as may occur during a football or rugby tackle. This injury is sometimes seen in combination with a medial meniscus tear and MCL injury, which is termed “O’Donohue’s triad”.

Clinically Relevant Anatomy

The ligament has a proximal attachment in a fossa on the posterior portion of the medial side of the lateral condyle of the femur and terminates distally on the tibial plateau in front of and lateral to the anterior tibial spine.^(14,16) There are two aspects of the ACL who can be broken.⁽¹⁴⁾ First the anteromedial; this one attaches on the proximal aspect of the femoral attachment and inserts on the anteromedial portion of the tibial insertion, this one is tight in flexion and lax in extension.⁽¹⁴⁾ The second, one the posterolateral band, comprises the remaining fibers that attach to the posterolateral portion of the tibial attachment, this one is lax in flexion and is tight in extension and prevents hyperextension. Thanks to this multiple-bundle the ACL is allowed to function at all angles of flexion.⁽¹⁴⁾

Epidemiology /Etiology

These injuries occur primarily in young, healthy individuals, most commonly as a result of sudden changes in direction or speed during physical activities such as sport.⁽¹³⁾ What’s special about an ACL injury is that the forces that cause these injuries are generated within the athlete’s body; other injuries involve a transfer of energy from a source external to the athlete’s body. ⁽¹⁵⁾ That’s why most of the time we speak about noncontact ACL injuries. In general there are three kinds of ACL injuries; direct contact, indirect contact and noncontact.⁽¹³⁾ The ACL’s primary function is to restrain anterior motion of the tibia with respect to the femur.⁽⁹⁾ When the rupture of the anterior cruciate ligament takes place, it gives a loud crack and an unstable feeling in the knee. When the knee is twisted violently, there will probably not only occur an injury to the anterior cruciate ligament.⁽¹³⁾ Often we also see that the medial ligament and medial meniscus are affected.⁽⁹⁾

Characteristics/Clinical Presentation

• ­ There may be an audible pop or crack at the time of injury
• ­ A feeling of initial instability, may be masked later by extensive swelling
• ­ A torn ACL is extremely painful, in particular immediately after sustaining the injury
• ­ Swelling of the knee, usually immediate and extensive, but can be minimal or delayed
• ­ Restricted movement, especially an inability to fully extension
• ­ Possible widespread mild tenderness
• ­ Tenderness at the medial side of the joint which may indicate cartilage injury.

These were proved in following articles:

Differential Diagnosis

We find the same characteristics for an ACL injury at knee dislocations and meniscal injuries. Other problems that has to be considered are patellar dislocation or fracture, and a femoral, tibial or fibular fracture. Often there is also an injury of the medial collateral ligament. 

Diagnostic Procedures

• The lachman test ⁽¹²⁾
• Anterior drawer⁽¹²⁾
  

• Pivot shift ⁽¹²⁾

Outcome Measures

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Examination

An organized, systematic physical examination is imperative when examining any joint. Immediately after the acute injury, the physical examination may be very limited due to apprehension and guarding by the patient. The basic examination should include the following:
The examiner should begin with inspection, looking for any gross effusion or bony abnormality. An immediate effusion indicates significant intra-articular trauma. According to Noyes et al, in the absence of bony trauma, an immediate effusion is believed to have a 72% correlation with an ACL injury of some degree. Assess the patient's range of motion (ROM), especially looking for lack of complete extension, secondary to a possible bucket-handle meniscus tear or associated loose fragment.Palpation of bony structures may suggest an associated tibial plateau fracture.Palpation of the joint lines to evaluate a possible associated meniscus tear. Palpation over the collateral ligaments to suggest any possible injury (sprain) of these structures. Up to 50% of ACL ruptures have associated meniscal injuries; acute injuries are likely to have associated injuries of the MCL and meniscus.
If the anterior drawer test is positive, it can be a sign that there is an ACL injury. The anterior drawer test is performed in 90° flexion of the knee. Swelling of the knee can make it impossible to make a flexion of the knee. Therefore we can also perform the Lachman test. This test is performed in 20-30° flexion of the knee. These tests are possibly positive if there is a hyper mobility of the joint. Sometimes it’s possible that there is another diagnosis, although the tests were positive. The doctors can also perform an MRI ( Magnetic Resonance Imaging ), that will make it easier to make the right diagnosis.

Medical Management

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Physical Therapy Management ( without / before surgery ) 

The first thing a person with an ACL-injury has to do is apply RICE. This stands for Rest, Ice, Compression and Elevation. In the therapy before an operation it is important to encourage strengthening of the quadriceps and hamstrings, as well as range of motion exercises. Performance of ROM will help the patient regain motion and strength.
Surgical treatment is usually advised in dealing with combined injuries (ACL tears in combination with other injuries in the knee). However, deciding against surgery is reasonable for select patients. Nonsurgical management of isolated ACL tears is likely to be successful or may be indicated in patients:
- With partial tears and no instability symptoms
- With complete tears and no symptoms of knee instability during low-demand sports who are willing to give up high-demand sports
- Who do light manual work or live sedentary lifestyles
- Whose growth plates are still open (children)

Key Research

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Resources

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Clinical Bottom Line

To understand what an ACL-injury is you need to have knowledge of the anatomy. You have to kwnow where the ACL is located, why it’s important to the knee and what it does with the knee.

Recent Related Research (from Pubmed)

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References

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