Utility of weight‐bearing radiographs compared to computed tomography scan for the diagnosis of subtle Lisfranc injuries in the emergency setting

Abstract

Objective The goal of the present study was to compare the diagnostic yield of weight‐bearing radiographs with non‐weight‐bearing computed tomography (CT) scan for subtle Lisfranc (LF) injuries in the ED. Methods Retrospective analysis of patients presenting with a suspected LF injury over a 2 year period from 2016 to 2017 who had both weight‐bearing bilateral foot radiographs and CT scan. Information extracted included patient demographics, radiographic findings of metatarsal fractures, fleck sign and measurements of diastasis between the medial cuneiform and second metatarsal expressed as a ratio of the uninjured side, clinical findings and treatment modality. Radiologist reports were recorded as either positive, negative or equivocal for a LF injury. Results A total of 117 patients were included with a mean age of 38 years and 54% (n = 63) women. When initial weight‐bearing radiographs were positive, 54% of subsequent CT scans were reported as either equivocal or negative. Of the patients who had a negative or equivocal weight‐bearing radiograph, only 12% had a positive CT scan. The mean diastasis ratio in patients undergoing surgery was 1.53 (95% confidence interval 1.41–1.65) compared to 1.11 (95% confidence interval 1.07–1.16) for patients with injuries not requiring operative intervention (P < 0.001). There was a statistically significant correlation between a positive weight‐bearing radiograph and surgical treatment (R = 0.339, P < 0.001), and between diastasis measurements and surgical treatment (R = 0.576, P < 0.001). Conclusions CT provides limited benefit in the diagnosis and initial management of suspected subtle LF injuries in the ED. We advocate for the use of bilateral weight‐bearing radiographs as a first‐line investigation.

Using area and volume measurement via weightbearing CT to detect Lisfranc instability

“…Prior reports that examine Lisfranc instability have employed weightbearing radiographs, conventional, non-WBCT scans, MRI and manual stress radiographs for diagnosis, but each of these modalities comes with inherent limitations. 3,11,[16][17][18] Weightbearing radiographs readily allow bilateral comparison under physiologic load but have limited sensitivity, especially as the instability becomes increasingly subtle. 3 Furthermore, radiographic evaluation of the Lisfranc joint necessitates an average craniocaudal X-ray beam angulation of 28.9°, which may be difficult to optimize in clinical practice or adapt to natural variations in patient anatomy.…”

“…3,11,[16][17][18] Weightbearing radiographs readily allow bilateral comparison under physiologic load but have limited sensitivity, especially as the instability becomes increasingly subtle. 3 Furthermore, radiographic evaluation of the Lisfranc joint necessitates an average craniocaudal X-ray beam angulation of 28.9°, which may be difficult to optimize in clinical practice or adapt to natural variations in patient anatomy. 16 In turn, cross-sectional MRI readily identifies Lisfranc ligament injury but not instability by virtue of being an unstressed modality with particularly poor bony detail in the acute trauma setting due to superimposed edema patterns.…”

“…1,2 Displaced injuries are readily diagnosed, but injuries that result in only subtle instability may be more difficult to identify, even with weight bearing radiographs. 3 Subtle Lisfranc instabilities usually have clinical signs and symptoms with equivocal initial non-weightbearing radiographs. 4 Clinical findings are pain over the Lisfranc joint, which can be reproduced by passive movement of individual metatarsal heads and the presence of plantar ecchymosis.…”

Lisfrancdislocatie herkennen

“…Röntgenfoto's die staand met belaste voet zijn gemaakt, geven een beeld van de verplaatsing van de botten, maar in de acute situatie is die positie meestal onmogelijk door de pijn. Opties om het letsel goed en snel in kaart te brengen, zijn: röntgenfoto's in meer- dere richtingen of een vergelijkende röntgenfoto van de gezonde voet om zo subtiele verschillen in kaart te brengen [5]. Een CT-scan geeft een duidelijker 3Dbeeld van de voet en het eventuele letsel dan röntgen [5,6].…”

“…Opties om het letsel goed en snel in kaart te brengen, zijn: röntgenfoto's in meer- dere richtingen of een vergelijkende röntgenfoto van de gezonde voet om zo subtiele verschillen in kaart te brengen [5]. Een CT-scan geeft een duidelijker 3Dbeeld van de voet en het eventuele letsel dan röntgen [5,6]. Echografisch onderzoek kan bijdragen aan een juiste diagnose bij een vermoeden op late gevolgen van een niet-herkend lisfrancluxatieletsel: in hoeverre is het dorsale ligament tussen het os cuneiforme mediale en metatarsale 2 intact?…”