Abstract
Introduction
Posterior malleolar fractures are present in up to 44% of all ankle fractures. Those involving > 25% of the articular surface have a higher rate of posterior ankle instability which may predispose to post traumatic arthritis. The posterolateral approach to the distal tibia allows direct reduction and stabilization of the posterior malleolus and concomitant lateral malleolus fractures. An anatomical study was performed to establish the safe zone of proximal dissection to avoid injury to the peroneal vessels in this uncommon approach.
Methods
26 unpaired adult lower limbs were dissected using the posterolateral approach to the distal tibia as described by Tornetta et al. The peroneal artery was identified coursing through the intraosseous membrane on deep dissestion as the flexor hallucis longus muscle was reflected medially. The level of its bifurcation was also noted over the tibia. Perpendicular measurements were made from the tibial plafond to these variable anatomical locations.
Results
The peroneal artery bifurcated at 83+/−21 mm (41–115mm) proximal to the tibial plafond and perforated through the interossoeus membrane 64+/−18 mm (47–96mm) proximal to the tibial plafond.
Conclusion
The safe zone for the posterolateral approach to the distal tibia is described. Caution is advised as the bifurcation and perforating artery may be as little as 41mm from the tibial plafond. This is important during deep dissection when the belly of the flexor hallucis longus muscle is reflected medially from the medial edge of the fibula. Once the peroneal artery was mobilized a buttress plate could easily be placed beneath it.
