Is there a Relationship between Bone Morphology and Injured Ligament on Imaging Studies and Laxity on Ankle Stress Radiographs?

Abstract

This study aimed to investigate the relationship between bone morphology and injured ligaments on imaging studies and laxity on ankle stress radiographs in patients with lateral ankle instability. In total, 115 patients who had undergone ankle MRI, ankle radiography, and stress radiography were included. Distal tibial articular surface angle, bimalleolar tilt, medial and lateral malleolar relative length, medial malleolar slip angle, anterior inclination of the tibia, and fibular position were measured on ankle radiographs. Tibiotalar tilt angle and anterior translation of the talus were measured on ankle stress radiographs. Degree of ligament injury was evaluated on ankle MRIs. Multiple regression analysis was performed using the following independent variables: age, sex, and factors significantly associated with ankle stress view on univariate linear regression analysis. Age (p=0.041), sex (p=0.014), degree of anterior talofibular ligament injury (p<0.001), and bimalleolar tilt (p=0.016) were correlated with tibiotalar tilt angle. Fibular position and degree of posterior talofibular ligament injury were factors significantly related to anterior translation of the talus. Differences in patient characteristics might predispose ankle stress radiograph results. Comparison of both ankles on stress radiographs is superior to applying fixed numerical values to the injured side in order to reduce the influence of patient factors.

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

“…Additionally, our study also revealed a significant anterior placement of the fibula compared to the normal population. Based on the literature [6,7], we think that a more posteriorly located fibula plays a role in the etiology of ankle sprains; therefore, a similar positioning of the fibula may be present in patients with ankle instability. However, we also contend that a more anteriorly located fibula is necessary for a lateral malleolar fracture to occur.…”

“…However, few studies have explored whether differences in anatomical morphology can predispose patients to fractures. It is generally accepted that having a "constrained" anatomy in the ankle may be a risk factor for fracture and that a less constrained anatomy may be a risk factor for ligament injury [5][6][7].…”

“…LMRL is the ratio of the lateral malleolus length to the talar dome width [6]. MMSA is the angle between the line parallel to the medial malleolar articular surface and the line parallel to the tibial plafond [7]. TCA is the angle between the line drawn perpendicular to the line parallel to the tibial plafond and the line connecting the endpoints of the lateral and medial malleoli [11].…”