Ultrasound as a Diagnostic Tool in the Assessment of Lisfranc Joint Injuries.

OBJECTIVES

Ligamentous Lisfranc injuries are frequently overlooked because of subtle clinical presentations and diagnostic difficulties. The dorsal Lisfranc ligament (DLL) is easily visualized with ultrasound (US), which can provide quick, cost-effective diagnoses of disorders but is not considered standard clinical practice. This study sought to compare DLL measurement accuracy between US and cadaveric dissection.

METHODS

Ultrasound images of 22 embalmed cadaveric feet were obtained with an M-Turbo US machine and a 6-13-MHz linear array (FUJIFILM SonoSite, Inc, Bothell, WA). Images were measured in the US unit and again with ImageJ software (National Institutes of Health, Bethesda, MD). Specimens were dissected, and DLL morphologic characteristics were recorded.

RESULTS

Twenty-two specimens were scanned, however 4 were excluded, leaving a sample of 11 male and 7 female cadaveric specimens (mean age ± SD, 80.3 ± 14.03 years). The DLL length differences between SonoSite (8.39 ± 1.27 mm) and ImageJ (8.25 ± 1.84 mm) were not significant (P > .05). Both US DLL measurements significantly differed from the gross dissection measurement (10.8 ± 1.85 mm; P < .001). The morphologic characteristics of the DLL at dissection were consistent. Overall, 70% to 80% of the ligament length was represented by US compared to dissection. The dorsal joint space did not differ significantly between SonoSite (2.19 ± 0.49 mm) and ImageJ (2.05 ± 0.52; P > .05). Both US measurements were also significantly larger than dissection measurements (1.04 ± 0.24; P < .001). Intraclass correlation coefficients indicated good reliability for the DLL length (0.835) and moderate reliability for the dorsal joint space (0.714).

CONCLUSIONS

The DLL is underrepresented but easily distinguished by US, demonstrating its utility in Lisfranc injury diagnosis. Thus, we propose a 4-component assessment involving US, which may provide more rapid, cost-effective diagnoses of subtle Lisfranc injuries.