ACL or Anterior Cruciate Ligament injuries are among some of the most common and costly to a young athlete’s career. They can lead to significant pain and disability, require extensive rehabilitation and can have ongoing consequences. 

An early and accurate diagnosis is not only crucial for the effectiveness of treatment but can also provide you with more treatment options at your disposal. This post will outline the process for diagnosing a potential ACL injury, including the importance of the clinical examination, imaging and consultations with an orthopaedic professional. 

The Diagnostic Process

It is important to seek a trusted medical professional, ideally who has experience in assessing, diagnosing and treating ACL injuries, as soon as you possibly can. Some potential treatment options have a time restriction, requiring an accurate diagnosis to be made within the initial days to first few weeks. 

The process to accurately diagnose an ACL injury involves a thorough subjective and objective examination, imaging, and where necessary, a consultation with an orthopaedic professional. This will reveal the presence and severity of an ACL injury, plus any specific characteristics or other injuries that may impact the decision making of treatment options. 

Subjective Assessment

The initial assessment begins with a therapist asking about your injury and can provide a great deal of information about the potential injury and will dictate the next steps of action. Describing your injury can give clues on the circumstances leading up to the injury, the likely involvement of the ACL and other potential associated injuries. 

Some of these important questions are: 

• When did the injury occur 
• How did the injury occur 
• What did you feel/hear when the injury occurred? (i.e. was there a popping sensation/sound?) 
• Where do you feel the pain?
• When did the swelling start? 
• Does the knee feel unstable or have you had an incident of it giving way?
• Have you had an injury to this knee before?

A full discussion around your medical, family and sporting history, along with your goals and expectations around rehabilitation will follow. 

The Objective Assessment 

The objective assessment involves both observational and hands-on testing to provide further insights on the structural integrity of the knee joint. These can add to our suspicion of an ACL injury, or other structural injuries being present. 

Physical measures around swelling, palpation, joint range of motion and functional tests will be performed in a clinical setting, before moving to a series of ‘special tests’ that can indicate a potential specific structural involvement. Some, but not all, of those tests are:

Lachmann test (ACL Injury) – The therapist can stabilize the femur, while providing an anterior force to the tibia, and assess for increased anterior translation of the tibia or a loose end feel. If positive, this test is highly accurate of an ACL injury. 

McMurray test (Menisci Injury) – The therapist can move the knee joint to assess for clicking, catching or locking sensations, which may indicate potential menisci injury. 

Varus and Valgus Stress Tests (MCL and/or LCL injury) – The therapist can provide a force to the inside or outside of the knee, assessing the structural integrity of the MCL and LCL, respectively. 

Posterior Drawer Test (PCL injury) – The therapist can apply a force to the tibia posteriorly, while stabilising the femur. Increased posterior translation compared to the uninjured knee and a loose end feel may indicate a potential PCL injury. 

The Role of Imaging

Magnetic Resonance Imaging (MRI) is currently the gold standard when it comes to imaging and diagnosing knee injuries. It can provide a visual insight of the structure of an ACL, while revealing any potential other injuries involving the other ligaments, menisci, tendons and other structures.

MRI’s can often help confirm our suspicions based around the therapists subjective and objective examinations. Depending on the severity of injury, involvement of other structures and then the time taken to reach an accurate diagnosis, can determine the available treatment options. 

Consultation With an Orthopaedic Professional

Once an ACL injury has been confirmed, a consultation with an orthopaedic specialist is recommended. Orthopaedic surgeons are specialised medical professionals who can provide their insights and expertise into the shared decision-making process around treatment options, whether that be surgical or non-surgical. A collaborative approach between patient, therapist and surgeon ensures that the most appropriate treatment option is selected. 

Conclusion 

ACL injuries are incredibly common and devastating to young athletes around the world. Early and accurate diagnosis is crucial in order to make an informed decision around treatment options, prevention of further damage and improve the likelihood of a successful rehabilitation. 

Stay tuned for my next blog post on the potential treatment options around ACL injuries.