Posterior approach for medial column beam screw in midfoot Charcot reconstruction: technique and structures at risk.

Charcot neuroarthropathy is frequently recognized as a major cause of morbidity in patients with neuropathic diabetes mellitus. Recently, intramedullary beam screw fixation has been used for midfoot Charcot reconstructions. Ten below-the-knee cadaveric specimens were used to demonstrate an antegrade, posterior approach for placement of a medial column beam screw, with specific attention to the proximity of the anatomic structures at risk. Six structures at risk were identified, including the sural nerve, ankle joint, flexor hallucis longus tendon, Achilles tendon, neurovascular bundle, and peroneal tendon sheath. The sural nerve was the most commonly injured structure, injured in 50% of the limbs. The Achilles and flexor hallucis longus tendons were injured in 20% and the ankle joint in 10% of the limbs. The neurovascular bundle and peroneal tendon sheath were located over 1 cm from the reference guidewire and were considered safe structures in this approach. Our results have demonstrated an alternative posterior approach to the delivery of an intramedullary medial column beam screw, instead of a retrograde technique beginning in the metatarsal heads. Our results have also made clear the need to be aware of the potential for damage to the sural nerve, Achilles tendon, flexor hallucis longus tendon, and ankle joint.