Post-operative radiological predictors of satisfying outcomes occurring after intra-articular calcaneal fractures: a three dimensional CT quantitative evaluation.

PURPOSE: No functional outcome related to 3-D CT evaluations for calcaneal fractures has been presented. The aims of this study are to analyze the post-operative morphological parameters of calcaneal fractures in 3-D space and to correlate the 3-D morphological parameters with functional outcomes.
METHODS: Between 2009 and 2015, 156 patients operatively treated for displaced calcaneal fractures were retrospectively reviewed with an average follow-up time of 32.4 months. Böhler's angle, Gissane's angle, the length of calcaneal axis, the height of posterior facet, the length of posterior facet, and the subtalar joint congruity were evaluated post-operatively in accordance with 3-D CT. Each parameter was quantified, and then its association with the clinical outcomes assessed by the AOFAS score and Short Form-36 questionnaire was evaluated.
RESULTS: The restoration of the length of calcaneal axis, the height of posterior facet, and the length of posterior facet had no significant correlation with the clinical outcomes (P > 0.05). The restoration of Böhler's angle and Gissane's angle had significant correlation with the better AOFAS score (P < 0.001), while no correlation was found with the SF-36 physical component summary score (P > 0.05). No significant association emerged between the clinical outcomes and reconstruction of the posterior facet congruity (P > 0.05).
CONCLUSION: The predictable functional outcome is related to the reconstruction of post-operative morphological characteristics of the calcaneus as evaluated on 3-D CT, especially the Böhler's angle and Gissane's angle. Despite post-operative step-off of the posterior facet exiting, the clinical outcomes appear to be not related to the posterior facet congruity.