Clinical evaluation of dorsal Lisfranc ligament deformation with change in load using ultrasound imaging

Abstract

Preface: The use of ultrasound is a viable modality for medical imaging of ligamentous tissue. In a previous study we showed that the dorsal Lisfranc Ligament (dLL) can be reliably visualized with ultrasound and that we can potentially discern load-varying ligament deformationwith the images obtained. The studywas limited with respect to the artificial loads used to apply stress on the foot using a calf raise machine. Purpose:The goal of thepresent studywas to load the foot using physiologically relevant stresses in a clinical setting and assess the dLL deformation from the acquired ultrasound images. We expect that these results will contribute towards the development of a protocol for Lisfranc ligament injuries diagnosis. Methods: Bilateral dLL measurements were taken from fifty healthy volunteers (25 males and 25 females), for a total of one hundred asymptomatic feet, using sonographic imaging technology under three different stress conditions (low, medium and high load). Stress load was applied using the individuals’ body weight (low load – seated position; medium load – equal weight bearing standing position; and high load – single leg standing). Two floor imbedded force plates were used to measure the exact physiological load. Digital images of the dLL obtained using a 10.0MHz linear array ultrasound transducer were analyzed to determine ligament parameters using software written in MATLAB. Results: One-way repeated measures ANOVA revealed a statistically significant increase in the dLL length with load. The average dLL elongation, as percent change, was 7.43±0.98% (pooled bilaterally) between seated and single leg standing positions. Most of the dLL length change (6.02±1.05%) occurred between seated and bilateral standing positions. Conclusion:Ultrasound imaging canbeused tovisualize thedLL and can detect ligament elongation that reflects increase in physiological load, making ligament imaging clinically practical. These clinically practical findings may prove useful in protocol development that uses ultrasound as a clinical imaging technique to diagnose Lisfranc ligament injuries.