Which test is diagnostic of Achilles tendon rupture?

• A. Lachman test
• B. Thompson test
• C. Anterior drawer test
• D. Varus stress test

Answer: (B)

The key idea is that Achilles tendon rupture is diagnosed by a bedside test that directly checks the tendon’s ability to transmit the muscle’s force. Squeezing the calf (the gastrocnemius-soleus complex) should cause the foot to plantarflex if the Achilles tendon is intact. When the tendon is ruptured, this plantarflexion does not occur, so the ankle remains neutral or dorsiflexed, often with a palpable gap where the tendon has torn. This makes the calf squeeze test, also known as the Thompson test, a diagnostic bedside sign for rupture.

The other tests target different joints and structures (for example, knee ligaments) and don’t assess the Achilles tendon, so they don’t provide a direct diagnostic assessment for this injury.