Diagnosis in anterior cruciate ligament injury: The lachman test and the anterior drawer test

When diagnosing an anterior cruciate ligament injury, we often use specific clinical tests, such as the Lachman test and the anterior sliding drawer test. These tests help us assess the integrity of the anterior cruciate ligament and determine the severity of the injury.

The Lachman test: The Lachman test is a widely used and relatively well reliable method to diagnose an ACL injury. During this test, the patient lies on their back with the injured leg slightly flexed. The physiotherapist stabilises the upper leg with one hand and tries to pull the lower leg forward with the other hand. A positive Lachman test missing the cord phenomenon. When the lower leg is pulled forward with a snuk, inhibition by the anterior cruciate ligament normally takes place. The cord phenomenon is then present. We can also possibly make a statement about an enlarged forward movement of the lower leg relative to the upper leg. This combined with the absence of Cord, indicates a possible tear of the anterior cruciate ligament.

The Front Drawer Test: The Anterior sliding drawer test is another important diagnostic tool for ACL damage. In this test, the patient also lies on their back, but the knee joint is bent at a 90-degree angle. The physiotherapist places both hands behind the lower leg and gently pulls the lower leg forward. A positive anterior sliding drawer test is characterised by an enlarged forward displacement of the lower leg, indicating damage to the anterior cruciate ligament.

At Fysio Fitaal Tilburg, we use the International Knee Documentation Committee (IKDC) to evaluate the severity of ligament injuries in the knee. The IKDC system provides a detailed and standardised method to assess the degree of injury to the various ligaments in the knee. Below, we explain the different degrees of ligament injury according to the IKDC system.

IKDC grades for ligament injury range from Grade A to Grade D. They are based on the degree of abnormal movement or also known as play in the knee. Each grade indicates a specific range of displacement or rotation, measured in millimetres (mm) or degrees (°).

1. Grade A: Minimum Displacement
   • Anterior cruciate ligament (ACL) - Lachman Test: 0-2 mm displacement
   • Rear Cross Band (AKB) - Rear Slide Tray Test in 70° Flexion: 0-2 mm displacement
   • Superficial Medial Collateral Ligament (sMCL) - Medial Joint Opening in 20° Flexion with Valgus: 0-2 mm displacement
   • Lateral Collateral Ligament (LCL) - Lateral Joint Opening in 20° Flexion with Varus: 0-2 mm displacement
   • Posterolateral Angle (PLC): < 5°
2. Grade B: Moderate Displacement
   • VKB, AKB, sMCL or LCL: 3-5 mm displacement
   • Posterolateral Angle: 6-10° rotation
3. Grade C: Substantial Displacement
   • VKB, AKB, sMCL or LCL: 6-10 mm displacement
   • Posterolateral Angle: 11-19° rotation
4. Grade D: Severe Displacement
   • VKB, AKB, sMCL or LCL: > 10 mm displacement
   • Posterolateral angle: > 20° rotation

Meaning of Gradations

• Grade A (0-2 mm): This grade indicates minimal clearance, indicating that the ligaments in the knee are still largely intact and the knee remains stable. There is often the presence of the cord phenomenon. Treatment can often be conservative with physiotherapy to strengthen the muscles around the knee. 
• Grade B (3-5 mm): Moderate displacement suggests some degree of ligamentous damage. There is a noticeable instability that can be both functional and symptomatic. Cord is also often still present at this grade. A combination of physiotherapy and possibly brace use may be required.
• Grade C (6-10 mm): Substantial displacement indicates significant ligamentous damage. There is marked instability affecting daily activities and sports performance. Here, there is usually no more Cord. This may often require surgical intervention followed by an intensive rehabilitation programme.
• Grade D (>10 mm): Severe displacement indicates severe ligamentous damage, often a complete tear with missing Cord. The knee is highly unstable and surgery is usually necessary to restore stability. Postoperative rehabilitation is extensive and lengthy.

To confirm the diagnosis and determine the severity of the injury, imaging studies are often used. A magnetic resonance imaging (MRI) scan is the gold standard here, as it can provide detailed images of the soft tissues in the knee, including the anterior cruciate ligament. 

Combining history, physical examination and imaging techniques allows us to make an accurate diagnosis. This is vital in determining the most appropriate treatment options, whether conservative treatment such as physiotherapy or surgical reconstruction of the anterior cruciate ligament.

When anterior cruciate ligament damage is suspected, imaging studies will be advised to confirm the diagnosis and have an orthopaedic doctor assess the severity of the injury. In the case of an anterior cruciate ligament injury, an MRI, or magnetic resonance imaging, is the gold standard for diagnosing a VKB injury. The gold standard in the medical world refers to the most reliable and widely accepted method or test for diagnosing or treating a disease or condition. This examination provides a detailed description of the knee joint and properly identifies the extent of damage. Any additional damaged structures such as the meniscus, cartilage and other ligaments can also often be clearly seen on an MRI. 

X-rays are mainly used to assess bone structures. In the case of knee injuries, they are useful to rule out fractures that might occur in acute knee trauma. Not very likely in an anterior cruciate ligament injury, especially when there was no substantial contact moment. You have to think here of forces released in a car accident or hard fall from a bicycle, for example. 

Ultrasound can be useful in assessing superficial structures of the knee and in acute injuries. It is particularly suitable for evaluating superficial ligaments and tendons and less suitable for deeper structures such as the VKB. However, we do see that equipment is becoming more sophisticated and better. There are studies that are tentatively starting to make a statement about potentially being able to diagnose anterior cruciate ligament injury by ultrasound. Ultrasound is a much cheaper and faster alternative when compared to an MRI scan. Who knows what will be possible in the future. 

Diagnosing an anterior cruciate ligament (ACL) injury is a crucial part of the treatment process. An accurate and timely diagnosis allows doctors and physiotherapists to develop the most appropriate treatment strategies, increasing the chances of a successful recovery. Through a thorough history, detailed physical examination and advanced imaging techniques such as MRI, we can get a complete and accurate picture of the nature and severity of the injury.

At Fysio Fitaal in Tilburg, we are ready to guide you through every step of this process. Our expert sports physiotherapists have the knowledge and experience to not only help you get diagnosed, but also to support you throughout the rehabilitation process. We understand how important it is to return to your sport or daily activities quickly and safely, and work with you to achieve this goal.

Are you dealing with a possible anterior cruciate ligament injury or do you have questions about diagnostics for an anterior cruciate ligament injury? If so, don't hesitate to contact us. At Fysio Fitaal, we are here to help you optimise your health and performance. Together, we will make sure you come back stronger than ever before.