The Effects of Fibular Malrotation on Tibiotalar Contact Area and Peak Pressure Distributions in Weber B Ankle Fractures

Abstract

Category: Basic Sciences/Biologics; Ankle; Hindfoot; Trauma Introduction/Purpose: Decreased tibiotalar joint contact area (CA) and increased peak pressure (PP) following rotational ankle fractures may predispose the development of post-traumatic osteoarthritis. Previous studies have highlighted the effects of lateral talar translation on tibiotalar joint congruity. However, debate remains regarding surgical indications in minimally displaced (0.05) increases in tibiotalar CA at all stance phases following malreduction. Significant (p>0.05) increases in tibiotalar PP were seen mid-stance following a simulated Weber B fracture, and these changes were shown to be greatest in the malreduced state versus the anatomically fixed state (7.21 MPa vs. 6.35 MPa respectively, p = 0.004). Interestingly, similar (p=0.84) decreases tibiotalar PP were shown during plantarflexion following a simulated Weber B fracture fixed in both the anatomically fixed and malreduced state. Conclusion: Our preliminary data supports the notion that significant changes in tibiotalar PP occur following ankle fractures even in an anatomically fixed state. Increases in tibiotalar PP seem to be further amplified following malreduction at specific stance phases. Further data collection is needed to validate these findings, and to determine the role of malrotation as a potential surgical indication for minimally laterally displaced ankle fractures.