Correlation Between Postoperative Morphologic Changes of Ankle Mortise and Ankle Joint Function After Pilon Fracture

Objectives: We aimed to explore the correlation between the postoperative morphologic changes of ankle mortise and ankle joint function after Ruedi-Allgower type III pilon fracture. Methods: A retrospective analysis was performed for 60 patients with Ruedi-Allgower type III pilon fractures receiving surgical treatment. The height, width, depth, coronal angle, and sagittal angle of ankle mortise were measured based on X-ray films during the last follow-up. The ankle joint function on the injured side was scored according to the Mazur ankle grading scale, and the patients were divided into an excellent group (n = 41), a good group (n = 12), and a mediocre + poor group (n = 7). Results: The correlation between the morphologic changes of ankle mortise and function was analyzed by comparing the five indices of ankle mortise on injured and healthy sides. The injured and healthy sides had significantly different widths, depths, and coronal and sagittal angles of ankle mortise. The differences between the indices of ankle mortise on injured and healthy sides, except for that between heights, were negatively correlated with scores. The differences increased with decreasing score. Effective treatment of the width and depth, together with coronal and sagittal angles of ankle mortise, was significantly correlated with postoperative ankle joint function. Conclusions: Anatomical reduction for the width, depth, and coronal and sagittal angles of ankle mortise of patients with Ruedi-Allgower type III pilon fractures exerts significant positive effects on ankle joint function. Thus, the anatomical form of ankle mortise should be restored as much as possible during surgery.