Review of Ankle and Foot Tendon Transfers, Emphasizing Indications, Anatomy, and Imaging Appearances.

Ankle and foot tendon transfer involves moving a tendon from its anatomic location to another location to reinforce a weakened muscle-tendon unit. An ideal donor tendon should have appropriate strength, excursion, phase, and tensioning. Imaging plays an important role in treatment selection and pre- and postoperative evaluation. Radiographs enable assessment of hardware position, bone tunnels, and foot alignment. Weight-bearing views or CT provides a more precise evaluation of alignment, potentially uncovering flexible deformities. MRI depicts the status of the donor and transfer sites and both bone and soft-tissue complications. There are three common indications for a tendon transfer. The first is reinforcement or replacement of a diseased tendon. Flexor digitorum longus to posterior tibial tendon (PTT) transfer is a popular method to address PTT dysfunction. Flexor hallucis longus to Achilles tendon (AT) transfer is used to address a tendinotic or partially torn AT. The second indication is restoration of bone alignment. Anterior transfer of the PTT or peroneus longus (PL) is a treatment option for footdrop. The choice depends on whether peroneal neuropathy is partial or complete. Options for varus deformities are anterior tibial tendon (ATT) transfer, split transfers (ATT or PTT), and PL to peroneus brevis (PB) transfer. The final indication is correction of lateral ankle or subtalar joint instability. Current techniques involve PB looping (Watson-Jones, Lee, Castaing), rerouting (Evans), or both (Chrisman-Snook). These have been abandoned in favor of other anatomic procedures, although some are still being performed and will likely still be encountered by the radiologist. ©RSNA, 2025 Supplemental material is available for this article.