Can Anatomical Differences Contribute to the Etiology of Danis-Weber Type B Lateral Malleolus Fractures?

Abstract

IntroductionLateral malleolus fractures are among the most common ankle fractures, but the anatomical factors that may predispose individuals to this specific type of fracture are not fully understood. This study aims to explore whether distinct anatomical characteristics of the ankle joint contribute to an increased susceptibility to lateral malleolar fractures. MethodsA retrospective analysis was conducted on 73 patients diagnosed with isolated lateral malleolar fractures between 2020 and 2023. An array of radiologic parameters, including distal tibial articular surface (DTAS) angle, bimalleolar tilt (BMT), medial malleolar length (MML), lateral malleolar length (LML), medial malleolar relative length (MMRL), lateral malleolar relative length (LMRL), medial malleolar slip angle (MMSA), talocrural angle (TCA), anterior inclination of the tibia (AI), and fibular position (FP), were meticulously measured on anteroposterior and lateral ankle radiographs for each study participant. We also measured the same parameters in 126 individuals who had not experienced an ankle fracture for comparison. ResultsStatistically significant differences were observed between the fracture group and the control group for DTAS angle, BMT, MML, MMRL, LMRL, TCA, AI, and FP (p<.05). Conversely, LML and MMSA displayed no significant variations between the two groups (p=0.745 and p=0.623). Effect sizes were notably large for DTAS and TCA, medium for MMRL, BMT, and AI, and small for LMRL, MML, and FP. ConclusionOur findings indicate an increased risk of lateral malleolus fractures in individuals with a relatively longer medial malleolus, a valgus-oriented ankle, reduced anterior inclination of the tibia, and an anteriorly positioned fibula. Taking protective measures during risky activities in individuals with these differences may help to prevent fractures.