What should be done on physical exam for a patient with a suspected Achilles tendon rupture?

Physical Examination for Suspected Achilles Tendon Rupture

The physical examination for suspected Achilles tendon rupture should include at least two of the following tests: Clinical Thompson test, assessment of ankle plantar flexion strength, palpation for a gap in the tendon, and evaluation of passive ankle dorsiflexion. 1

Essential Physical Examination Components

Primary Tests (Perform at least two)

1. Clinical Thompson Test (Simonds Squeeze Test)

   • Position: Patient prone with feet hanging over edge of examination table
   • Technique: Squeeze the calf muscle
   • Positive finding: Absence of plantar flexion of the foot indicates rupture
   • Note: Highly sensitive test for complete rupture

2. Ankle Plantar Flexion Strength Assessment

   • Technique: Ask patient to actively plantar flex against resistance
   • Positive finding: Decreased strength compared to uninjured side
   • Note: Complete rupture typically results in significant weakness

3. Palpation for Gap

   • Technique: Palpate along the Achilles tendon course
   • Positive finding: Presence of a palpable gap or defect, often 2-6 cm proximal to insertion
   • Note: Most easily felt in acute phase before significant swelling develops

4. Passive Ankle Dorsiflexion

   • Technique: Gently manipulate the ankle into dorsiflexion
   • Positive finding: Increased passive dorsiflexion compared to uninjured side
   • Note: Indicates loss of tendon continuity

Examination Timing Considerations

For optimal diagnostic accuracy, if the initial examination is inconclusive due to pain or swelling:

• Consider delaying definitive clinical assessment for 4-5 days post-injury
• Delayed examination using the anterior drawer test has excellent sensitivity (84%) and specificity (96%) 1

Additional Assessment Elements

• Weight-bearing ability: Inability to bear weight immediately after injury is concerning
• Inspection: Look for swelling, ecchymosis, and altered contour of the posterior ankle
• Location of tenderness: Precise localization helps differentiate from other conditions
• Bilateral comparison: Always compare with the uninjured side

Common Pitfalls to Avoid

1. Misdiagnosis as ankle sprain: Up to 20% of Achilles tendon ruptures are initially misdiagnosed 2
2. Relying on a single test: Using only one physical examination test increases risk of missed diagnosis
3. Failure to recognize partial ruptures: These may present with less dramatic findings
4. Overlooking pre-existing tendinosis: Chronic tendinopathy may predispose to rupture 3
5. Not considering contralateral risk: Patients with one Achilles rupture have significantly higher risk of contralateral rupture 4

Diagnostic Algorithm

1. Perform at least two of the four primary physical tests listed above
2. If two or more tests are positive, diagnosis of Achilles tendon rupture is likely
3. If examination is limited by pain/swelling and diagnosis is uncertain:
   • Consider re-examination after 4-5 days
   • Consider imaging studies if clinical suspicion remains high

Remember that early and accurate diagnosis is crucial for optimal management and outcome of Achilles tendon ruptures.