Anterior Drawer Test: Anterior Cruciate Ligament Test

Anterior Drawer Test: Its definition and how it is Performed:

The Anterior Drawer Test is a common clinical test applied mainly for the assessment of the ACL knee injury. Often it is used as one of the standard orthopedic tests to confirm ACL pathology though it is very valuable in the assessment of patients with knee instability after the trauma. This test is one of the essential assessment tools used by physiotherapists and other health care professionals involved in dealing with the musculoskeletal system particularly in sports and orthopedic practice.

Indeed, one of the major utilities of the Anterior Drawer Test is in the identification of anterior tibial translation, which in turn helps in assessment of the functional stability of the knee joint. It could be quite expected when the test comes out positive and it means there is an injury on the ACL which is a stabilizing ligament of the knee. 

Purpose of the Anterior Drawer Test: Ligament Injuries – A Diagnostic Approach

The main purpose and test for Anterior Drawer Test is for evaluation of indicated anterior instability in the knee joint which is characteristic of ACL injury. The ACL plays a significant role in keeping the tibia from moving forward too much, and any damages to this ligament alter the stability of the knee joint.

This test is most often performed to assess an ACL tear, which can occur by any of the following mechanisms: sudden change of direction, pivoting or direct impact on the knee. Soccer players, basketballers, and football players are at the most likely to develop ACL injuries that affect their sports agility and the wellbeing of their knees moving forward.

Anatomy Involved in the Anterior Drawer Test

The Anterior Drawer Test, as the name suggests targets the crucial stabilizer of the knee joint, the anterior cruciate ligament (ACL). The ACL arises from the lateral side of the medial femoral condyle and attaches on the underside of the tibia in the area between the two condyles which is known as the intercondylar area. Its function is to stop movement of the tibia anteriorly as compared to the femur and offer the knee rotational stability.

Anterior structures involved during the test indirectly include the medial and lateral collateral ligaments (MCL / LCL),the menisci, and the joint capsule. Because an ACL injury is commonly combined with other injuries to other structures in the knee joint, this test is very useful in the overall examination of a knee.

Indications for the Anterior Drawer Test

The Anterior Drawer Test is indicated in several clinical scenarios, mainly involving knee injuries or instability:

ACL Injury

The most common indication is suspicion of anterolateral cruciate ligament tear especially after a knee trauma. This condition mainly presents with pains, fluctuations in swelling and stability particularly in activities such as; change in speed or direction.

Knee Instability

In patients who experience knee version, a “giving way” of the knee or pain and swelling that prevents them from putting their full weight on the leg, must have ligamentous instability. The Anterior Drawer Test actually enables us to define whether the ACL is the reason for this instability.

Post-Trauma Knee Assessment

Following any severe knee injury especially to the athletes, the test comes in handy to determine whether there is an involvement of the ligamentous structures and the subsequent plan of imaging studies.

Sports Injuries

It is also common to see strong athletes in high impact sports such as basketball and football strains their or her ACL. This test is a part of their baseline examination and should also be implemented before the patient starts physical activities which mean they should include this test in their management plan before the patient starts playing again.

Post-Surgical Evaluations

In particular, when conducting subsequent checkups of patients who have recently undergone ACL reconstructive surgery, one can use the Anterior Drawer Test to assess the efficiency of the surgery and the viability of the graft.

How to Perform the Anterior Drawer Test: A Step-by-Step Guide

Patient Positioning

The patient should be placed in supine position such that their knee is in a right angle with the tibia parallel to the examination table and plantar surface of the foot resting on the table. This adds extra motion to the knee flexion and in turn puts tension on the ACL thus, making the test more sensitive.

Therapist Positioning

Ideally, the therapist has to be positioned at the foot end of the examination table and face the patient. To perform the test, the therapist immobilizes the patient’s foot by either sitting on it or using his or her hands to prevent the leg from moving during the test. Palms must be placed on the proximal tibia above the joint of the knee and thumbs should be placed on tibial tuberosity while fingers encircle the calf.

Performing the knee anterior drawer test

With the patient’s foot placed immediately on the therapist’s distal thigh, the therapist exerts an anterior force on the patient to bend the knee joint with the tibia moved forward from the femur. It is recommended that this motion should be done with constant force in order to quantize the extent of the shift of the anterior tibia.

Observation and Key Findings

This is actually how much forward movement the tibia makes and the therapist monitors the amount of forward progression during the test. A positive test is where the patient has increased anterior displacement compared with the unaffected limb or if the examiner feels that the patient’s end-feel is ‘soft,’ which suggests the ACL is torn or otherwise damaged.

Outcome Measures of the Anterior Drawer Test

Positive Test

A positive anterior drawer test ankle  will give a shift to the tibia to the anterior position than in the negative side or no end feel. Based on this fact alone it points strongly towards a tear in the ACL. This anterior drawer test positive  is especially important to perform to have a reference point of that particular patient’s normal status before he/she was injured.

Negative Test

A negative trial, therefore, suggests that the ACL is likely to be structural as there is little, if any, anterior translation of the tibia and there is a hard end feel when the tibia is pulled forward.

Differential Diagnosis with the Anterior Drawer Test

Consequently, in the process of implementing the Anterior Drawer Test it is necessary to take into account other possible causes which may also mimic ACL abnormalities. These include:

1. Posterior Cruciate Ligament (PCL) Injuries:Full thickening may be obscured by a posterior sag thus the need to assess the PCL.
2. Meniscal Tears: These may produce joint locking or give way sensation, which is akin to ligament instability.
3. Collateral Ligament Injuries (MCL/LCL): These injuries, therefore, should present knee instability and should not be confused with ACL tears.
4. Patellar Subluxation: Can result in a feeling of knee shifting which is frequently mistaken as ligament tear.

Related Tests to the Anterior Drawer Test

Several tests complement the Anterior Drawer Test in the evaluation of knee ligament injuries:

• Lachman Test: Commonly used for acute ACL injuries because of the higher detection rate in early stages of the disease.
• Pivot Shift Test: Applied in the evaluation of active knee instability most of which are chronic ACL injuries.
• Posterior Drawer Test: As for controversial aspects, evaluates the PCL, especially in the traumatic patients.
• McMurray Test: Tests used to determine the condition of the meniscus, sometimes done along with an ACL test due to high likelihood of their co-involvement.

Latest Research on the Anterior Drawer Test

Some of the newest publications have pointed to the need to use Anterior Drawer Test alongside other clinical examinations and/or imaging studies for the purpose of improving outcomes when diagnosing ACL injuries. A number of investigations have found out that the Lachman Test and imaging like MRI may help enhance the Anterior Drawer Test especially in chronic or partial ACL injuries. Similarly, some of the research calls for dynamic knee testing and instrumented assessment methods in order to enhance accuracy of ACL injuries diagnosis.

Conclusion

Thus, the Anterior Drawer Test continues to be an essential part of the decision-making process for clinical diagnosis of the ACL injuries. Of all the skills, it is user-friendly, dependable and should be a core competency of physiotherapists; more so, those working in sports and orthopedic jurisdictions. ;Being aware of this test and its context among other diagnostic procedures.