Anatomic Analysis of a Percutaneous Fixation Technique for the Posterior Malleolus Using Posterior-to-Anterior-Directed Cannulated Screws: A Cadaveric Study and Technique Description.

Abstract

Posterior malleolus fractures are traditionally managed with open reduction and internal fixation or percutaneous anterior-to-posterior screws. We present a third option using a percutaneous technique for the placement of posterior-to-anterior-directed screws. An anatomic safety analysis is done using cadaveric specimens. Using 15 embalmed specimens (10 F and 5 M), a guidewire was placed using the described technique. The posterolateral ankle was dissected to evaluate for damage to vulnerable structures including the sural nerve, peroneal artery, and flexor hallucis longus/flexor digitorum longus/peroneal/Achilles tendons. The distance from the sural nerve and peroneal artery was measured to the guidewire at its nearest point. The tendons were evaluated for traumatic piercings. The sural nerve had a mean distance to wire of 5.3 mm (range 0 to 12) and the peroneal artery had a mean distance to wire of 5.7 mm (range 2 to 13 mm) with no traumatic piercings of either structure. The flexor hallucis longus/flexor digitorum longus/peroneal/Achilles tendons had no traumatic piercings. This percutaneous technique provides a safe alternative to the standard open and traditional percutaneous techniques. It has limited application and is suitable for noncomminuted minimally displaced posterior malleolus fractures and those with fragile tissues where the morbidity of the soft tissue exposure outweighs the benefit of an open reduction.