Long harvest of the flexor hallucis longus tendon in reconstructive foot & ankle surgery: A technique guide

Abstract

Reconstruction of the Achilles tendon for insertional disease, acute and chronic ruptures, severe mangling limb trauma, and tendon loss from necrotizing infections often results in a significant reconstructive challenge. Traditional issues that may be used to reconstruct the Achilles include a strip of the tensor fascia lata or tendon allograft. However, these tissues lack the inherent stability of autograft, are avascular and more subject to infection, and lack an intact functional muscle belly, providing no additional motor function to assist in plantar flexion. Functional muscle-tendon free flaps (such as the gracilis free flap) are complex, require microsurgical skills, and have a delayed and prolonged rehabilitation; they are a last resort to restore plantarflexion. Instead, tendon transfers are ideal to augment or substitute fully for the incompetent Achilles tendon. The most common tendon transfer to reconstruct the Achilles tendon is the flexor hallucis longus (FHL) tendon. The FHL tendon is vascularized, readily available, expendable, and provides in-phase plantar flexion function. Harvest of the FHL typically utilizes retrieval at the level of the subtalar joint, just deep to the posterior sulcus, or at the master knot of Henry in the midfoot. In the reconstruction of large Achilles defects, these harvest locations may produce an inadequate length of tendon for the reconstructive effort. The author provides an illustrative guide to harvest the full length of the FHL, which will provide enough tendon length for any Achilles reconstruction. Minimal donor morbidity can be expected by patients.