Cotton Test

What is the "Cotton Test" used for?

• Distal tibiofibular syndesmosis instability.

How to perform the "Cotton Test"?

• The patient is typically positioned supine or seated, the ankle is placed in a neutral position and the leg should be relaxed to avoid muscular guarding.
• The examiner stabilizes the distal tibia and fibula firmly with one hand. 
• With the other hand, the examiner grasps the patient’s foot. 
• A lateral translation force is applied to the foot relative to the tibia. 
• Important: This is a pure lateral translation, not an eversion force. The movement is assessed for excessive displacement or abnormal motion.

What is the positive result?

Normal Test: Minimal lateral translation with a firm end feel.

Positive Test:

• Lateral translation greater than 3–5 mm, and/or
• A palpable or audible “clunk”

A positive Cotton Test indicates syndesmotic instability, suggestive of partial or complete disruption of the distal tibiofibular ligaments.

Test Accuracy

• Sensitivity: 73.3%
• Specificity:100%