Trans-Achilles percutaneous fixation technique for posterior malleolus fracture: a cadaveric study.

Background: It has been reported that 43.6% of ankle fractures are accompanied by posterior malleolus fractures. The aim of this study is to define a safe zone for posterior malleolus fractures by determining the locations of the important anatomical structures in this region. Additionally, it aims to identify the trans-Achilles passage line for Kirschner wire insertion through a posteroanterior approach for posterior malleolus fragments.

Methods: Six below-knee amputee fresh-frozen leg cadavers were used in this study. A trans-Achilles Kirschner wire was applied to the cadavers in the posteroanterior direction under the guidance of fluoroscopy. The areas where the Kirschner wire passed were dissected, and their proximity to vital anatomical structures was measured.

Results: In all cadavers, the transverse thickness of the Achilles tendon at the level of the trans-Achilles Kirschner wire was 15.5 mm and the trans-Achilles Kirschner wire application was 18.6 mm from the sural nerve, 16 mm from the posterior tibial tendon, and 12.16 mm from the flexor digitorum longus muscle. It was performed 15.16 and 14.6 mm from the posterior tibial artery and vein, 12.3 mm from the tibial nerve, 13.6 mm from the tibiofibular joint, and 55.5 mm from the insertion site of the Achilles tendon to the calcaneus and at a sufficient distance from vital anatomical structures.

Conclusions: The proposed trans-Achilles percutaneous surgical technique is safe from neurovascular structures for fixing posterior malleolar fractures. However, the long-term clinical outcomes of this technique need to be explored.

Level of evidence: Level III, A cadaveric study.