The Anterior Drawer Test: Clinical Assessment for Ligament Instability
The anterior drawer test is a physical examination maneuver used to assess anterior displacement of the talus on the tibia, which indicates injury to the anterior talofibular ligament in the ankle or anterior cruciate ligament in the knee. 1
Ankle Anterior Drawer Test
Technique and Execution
- Patient positioned with knee flexed and foot relaxed in slight plantar flexion
- Examiner stabilizes the distal tibia with one hand while the other hand grasps the calcaneus
- The calcaneus is then pulled forward (anteriorly) while the tibia is held stationary
- Excessive anterior movement of the talus compared to the uninjured side indicates ligament damage
Diagnostic Value
- Sensitivity: 84% and specificity: 96% when performed 4-5 days after injury 1
- Early assessment (within 48 hours) is limited by pain and swelling 1
- When combined with other clinical findings (swelling, hematoma, pain on palpation), a positive test strongly suggests lateral ligament rupture 1
Key Clinical Considerations
- Optimal timing: Delay examination for 4-5 days post-injury for best accuracy 1
- A positive test indicates anterior talofibular ligament tear, with the talus subluxating anteriorly compared to the unaffected ankle 1
- In acute settings, excessive swelling and pain may limit examination reliability for up to 48 hours 1
Knee Anterior Drawer Test
Technique and Execution
- Patient supine with knee flexed to 90 degrees and foot flat on examination table
- Examiner sits on patient's foot to stabilize it
- Both hands grasp the proximal tibia with thumbs on the tibial plateau
- The tibia is pulled forward while the femur remains stationary
- Excessive anterior translation compared to the contralateral knee indicates ACL damage
Diagnostic Value
- Recent studies show sensitivity of 88.57% and specificity of 87.50% for ACL tears 2
- Modified anterior drawer test has shown improved diagnostic accuracy (92%) compared to the traditional test 3
- May be less effective in patients with large thigh circumference or when performed by examiners with small hands 4
Clinical Applications and Limitations
When to Use
- After acute ankle or knee trauma
- In patients with chronic instability complaints
- As part of a comprehensive ligament assessment protocol
Limitations
- Accuracy reduced in acute phase due to pain, swelling, and muscle guarding
- May be difficult to perform in patients with large thigh circumference (for knee examination) 4
- False negatives can occur with partial tears or when other structures provide secondary stability
Complementary Tests
- For ankle assessment: combine with Ottawa Ankle Rules to determine need for radiography 1
- For knee assessment: use in conjunction with Lachman test and pivot shift test for comprehensive ACL evaluation 3, 2
Interpretation of Results
Positive Test Indicators
- Excessive anterior translation compared to the uninjured side
- Soft or absent end-feel during the movement
- Patient apprehension or pain during the test
Grading System
- Grade 1: Slight laxity (1-5 mm displacement)
- Grade 2: Moderate laxity (5-10 mm displacement)
- Grade 3: Severe laxity (>10 mm displacement) with no firm endpoint
Clinical Pearls
- Always compare with the contralateral uninjured side
- Ensure patient relaxation to minimize muscle guarding
- For ankle assessment, optimal diagnostic accuracy is achieved when examination is delayed 4-5 days post-injury 1
- For knee assessment, consider the alternate Lachman test if the examiner has small hands or patient has large thighs 4
The anterior drawer test remains a valuable clinical tool for assessing ligamentous integrity, particularly when performed with proper technique and timing. Its high specificity makes it especially useful when positive, though negative results should be interpreted cautiously in the acute setting.