What is the purpose and procedure of the Anterior Drawer Test (ADT) in assessing knee stability, specifically in a young to middle-aged patient with a recent knee injury and possible anterior cruciate ligament (ACL) tear?

Anterior Drawer Test for ACL Assessment

Primary Purpose

The Anterior Drawer Test (ADT) is a physical examination maneuver designed to detect anterior cruciate ligament (ACL) tears by assessing anterior tibial translation relative to the femur, though it is less sensitive and more technically demanding than the Lachman test, which should be your primary diagnostic maneuver 1, 2.

Test Procedure

Patient Positioning

• Position the patient supine with the knee flexed to 90 degrees 3, 1
• The hip should be flexed to approximately 45 degrees 3
• The foot should be stabilized by the examiner sitting on it or holding it firmly against the examination table 3, 4

Execution Technique

• Grasp the proximal tibia with both hands, placing thumbs on the tibial plateau and fingers wrapped around the posterior calf 3, 4
• Apply anterior force to translate the tibia forward relative to the femur 3, 1
• Assess the amount of anterior translation and the quality of the endpoint 2
• Compare bilaterally - a difference of >5mm suggests ACL insufficiency 5

Critical Limitations

Why ADT Often Fails

The anterior drawer test has significant limitations that make it inferior to the Lachman test, particularly in acute injuries 1, 2:

• Hamstring guarding in acute injuries prevents adequate anterior tibial translation, producing false-negative results 3, 1
• Requires 90-degree knee flexion, which may be impossible or too painful in acute settings 3
• Technically difficult in patients with large thigh circumference (>43cm), where examiner proficiency drops to only 59% accuracy 4
• Examiner hand size matters - those with small hands (<21cm span) have particular difficulty performing this test accurately 4

Performance Characteristics

• Specificity: >90% when properly performed 2
• Sensitivity: Variable and significantly reduced in acute injuries due to muscle guarding 3, 1

Recommended Clinical Approach

Perform the Lachman test as your primary ACL assessment tool, not the anterior drawer test 1, 2. The examination sequence should be:

1. Lachman test first (30-degree knee flexion) - highest sensitivity and specificity, less affected by hamstring spasm 1, 2
2. Lever sign test - emerging as highly specific and easy to perform 1
3. Pivot shift test - most specific but requires experience 2
4. Anterior drawer test - use as confirmatory only, particularly in chronic injuries where muscle guarding is absent 3, 1

When ADT May Be Useful

• Chronic ACL deficiency where muscle guarding has resolved 3
• As a confirmatory test when Lachman is positive 1
• Follow-up examinations after acute pain and swelling have subsided 5

Additional Considerations

Concomitant Injuries

Always assess for associated injuries that commonly occur with ACL tears 2:

• Posterior cruciate ligament (PCL) - perform posterior drawer test
• Posterolateral corner (PLC) - dial test, external rotation recurvatum
• Posteromedial corner (PMC) - valgus stress testing
• Meniscal tears - McMurray test, joint line tenderness

Timing of Examination

Examine immediately after injury when possible - before significant effusion and muscle guarding develop 3. If delayed examination is necessary, consider ultrasound-assisted gravity drawer testing (prone position with 30-degree flexion), which shows 96% sensitivity and 98% specificity 5.

Common Pitfalls to Avoid

• Do not rely solely on ADT in acute injuries - it will miss ACL tears due to hamstring spasm 3, 1
• Do not force the examination if the patient cannot achieve 90-degree flexion due to pain or effusion 3
• Do not ignore bilateral laxity - always compare to the contralateral knee as some patients have constitutional laxity 4, 5
• Do not skip assessment of the entire kinetic chain including hip muscle function, as proximal weakness affects ACL injury outcomes 6