Posterior ankle release - operative indications

A "significant" equinus contracture for which one should consider the possible need to release more than just the Achilles tendon will be in excess of 20 degrees.

All posterior soft tissue structures may need releasing and this should be planned for. These structures are the Achilles, tibialis posterior, flexor hallucis longus, flexor digitorum, and posterior ankle capsule.

It is important to be aware at what levels the deformity is occuring. In particular to differentiate between a midfoot equinus and an ankle equinus. They may also co-exist. A midfoot equinus may be helped by an intercurrent plantar fascia release. In cases where the midfoot deformity is fixed a dorsal closing wedge osteotomy may be required.

In correcting a significant equinus contracture using an open technique the posterior skin is likely to be placed under significant tension and limited wound edge necrosis may occur. The Ilizarov technique of gradual lengthening of all the posterior soft tissues avoids this issue.