What is the most common mechanism for peroneal tendon dislocation?

• A. Chronic ankle instability.
• B. Sudden dorsiflexion with reflex contraction of the peroneal muscles.
• C. Rapid plantarflexion.
• D. Direct trauma without movement.

Answer: (B)

The situation tests how peroneal tendons tend to dislocate during a dynamic ankle movement. The typical event is a sudden dorsiflexion of the ankle coinciding with a reflexive, rapid contraction of the peroneal muscles. When the retinaculum that normally keeps the tendons in the retromalleolar groove is compromised (or the groove is shallow), this quick, forceful contraction can shove the tendons anteriorly out of place. Chronic ankle instability can make dislocations more likely to recur, but it isn’t the initiating mechanism. Rapid plantarflexion doesn’t produce the same anterior displacement, and direct trauma without movement generally causes other injuries rather than the dynamic tendon subluxation seen with this dorsiflexion-plus-contraction scenario.