Asymmetric lambda sign of the second tarsometatarsal joint on axial weight-bearing cone-beam CT scans of the foot: preliminary investigation for diagnosis of subtle ligamentous Lisfranc injuries in a cadaveric model

Trends in the Use of Weightbearing Computed Tomography

Background: This review aimed to critically appraise the most recent orthopedic literature around cone beam weightbearing computed tomography (WBCT), summarizing what evidence has been provided so far and identifying the main research trends in the area. Methods: This scoping review was performed on studies published between January 2013 and December 2023 on the Pubmed database. All studies (both clinical and nonclinical) in which WBCT had been used were critically analyzed to extract the aim (or aims) of the study, and the main findings related to the role of this imaging modality in the diagnostic pathway. Results: Out of 1759 studies, 129 were selected. One hundred five manuscripts (81%) dealt with elective orthopedic conditions. The majority of the analyses (88 studies; 84%) were performed on foot and ankle conditions, while 13 (12%) studies looked at knee pathologies. There was a progressive increase in the number of studies published over the years. Progressive Collapsing Foot Deformity (22 studies; 25%) and Hallux Valgus (19 studies; 21%) were frequent subjects. Twenty-four (19%) manuscripts dealt with traumatic conditions. A particular interest in syndesmotic injuries was documented (12 studies; 60%). Conclusions: In this review, we documented an increasing interest in clinical applications of weightbearing CT in the orthopedic field between 2013 and 2023. The majority of the analyses focused on conditions related to the foot and the ankle; however, we found several works investigating the value of WBCT on other joints (in particular, the knee).

The utility of point-of-care dynamic ultrasonography for the diagnosis of subtle isolated ligamentous Lisfranc injuries: a cadaveric study

OBJECTIVES

To assess if Lisfranc injury can be detected by US with and without abduction stress.

METHODS

Eight cadaveric feet were obtained. The following measurements were obtained in the uninjured feet: C1M2 and C1C2 intervals and TMT1 and TMT2 dorsal step-off distances. Measurements were obtained both with and without abduction stress using ultrasound. The injury model was created by transecting the Lisfranc ligament complex, after which the observers performed the measurements again. Statistical analysis was used to identify differences between intact and injured models, to determine diagnostic cut-off values for identifying Lisfranc injuries, and to assess interobserver/intraobserver reliability.

RESULTS

There was a significant difference in the mean C1M2 interval, both with and without abduction stress, between the intact and torn Lisfranc ligament (p < 0.001). A C1M2 interval with stress of > 2.03 mm yielded 81% sensitivity and 72% specificity for Lisfranc disruption. There was no significant difference in the mean C1C2 interval of the torn versus intact Lisfranc ligament without stress (p = 0.10); however, the distance was significantly different with the application of stress (p < 0.001). The C1C2 interval of > 1.78 mm yielded 72% sensitivity and 69% specificity for Lisfranc injury under stress. There were no significant differences in the mean TMT1 or TMT2 dorsal step-off measurements between the intact and torn Lisfranc ligaments. All observers showed good intraobserver ICCs. The interobserver ICCs for all measurements were good or excellent, except for TMT1, which was moderate.

CONCLUSION

Ultrasonography is a promising point-of-care imaging tool to detect Lisfranc ligamentous injuries when measuring C1M2 and C1C2 distances under abduction stress.

Weightbearing Computed Tomography vs Conventional Tomography for Examination of Varying Degrees of Lisfranc Injures: A Systematic Review of the Literature

Background

Lisfranc injuries, if not accurately diagnosed, can result in chronic pain and instability. Previous studies have examined ultrasonographs, radiographs, magnetic resonance imaging (MRI), and conventional computed tomography (CT) scan to differentiate Lisfranc instability, but they focused on a healthy/injured scale without differentiating subtle injury. Weightbearing CT (WBCT) has emerged as a diagnostic tool for detecting subtle Lisfranc injuries. This systematic review aimed to compare WBCT with conventional CT in diagnosing Lisfranc injury, and the ability to differentiate injuries of varying severities.

Methods

The review encompassed PubMed, CINAHL, MEDLINE, SPORTDiscus, and Web of Science databases from inception until July 5, 2023. Inclusion criteria involved studies on CT and/or WBCT for Lisfranc injuries and nonoperative studies. Exclusion criteria composed case reports, commentaries, postoperative imaging studies, pediatric patients, studies with nonobjective radiographic measurements, studies exclusively focused on injury classification, and studies with fewer than 5 patients because of poor statistical power. Data extraction focused on radiographic measurements of the Lisfranc complex, categorized into conventional CT, partial WBCT, and total WBCT.

Results

Out of the initially retrieved 489 articles, 9 met the inclusion criteria. Several studies consistently demonstrate that WBCT provides a higher level of accuracy in measuring the Lisfranc area, offering enhanced sensitivity to detect subtle alterations in joint structure. Moreover, WBCT exhibits superior sensitivity in distinguishing between healthy Lisfranc joints and those with injuries, particularly when identifying dorsal ligament damage. This imaging modality allows for the detection of significant variations in critical measurements like first-second metatarsal (M1-M2) distance, first cuneiform (C1)-M2 distance, and joint volumes, enabling a more comprehensive assessment of Lisfranc joint health especially with subtle instability.

Conclusion

This review evaluates the extant literature on WBCT's utility in diagnosing Lisfranc injuries and compares its effectiveness to CT in distinguishing between injuries of varying severity. WBCT, with reliable measurement techniques, appears more adept at detecting subtle Lisfranc instability compared to CT, likely by allowing the assessment of injury under load.

Retrospective chart review: Weightbearing CT scans and the measurement of the Lisfranc ligamentous complex

BACKGROUND

Lisfranc Ligamentous Complex (LLC) injuries are commonly misdiagnosed due to their unreliable projection on plain films. Weightbearing CT (WBCT) scans are a relatively new imaging modality that has not yet been utilized to establish widely referenced baseline anatomic positions.

METHODS

A retrospective chart review was conducted of patients who had undergone weightbearing CT of the bilateral lower extremities with one-hundred and twelve being included (56 patients). Measurements of the Lisfranc joint were collected by two independent reviewers. Uninjured symmetric anatomy was used to describe a baseline for normal anatomic variation and to evaluate for sex-based or age-related differences. These measurements were then compared against the injured side.

RESULTS

In patients without Lisfranc injury, the 1st metatarsal base to 2nd metatarsal base distance (Base M1-M2) was 2.7 + /- 0.7 mm; 2nd metatarsal base to medial cuneiform (M2-C1) was 3.7 + /- 0.7 mm; intercuneiform distance was 1.2 + /- 0.3 mm; and sagittal descent 12.2 + /- 5.4 mm. Patients with injury to LLC had a larger M1-M2 base distance (Δ = 0.5903, p < 0.0001) and M2-C1 interval (Δ = 1.8008, p < 0.0001) compared to uninjured side. Males had significantly higher M2-C1 (p = 0.0031), intercuneiform distance (p = 0.0039), and sagittal descent (p = 0.0008) compared to female patients. No significant differences were found between left versus right side in any of the measurements. Intercuneiform distance (p = 0.0039) was found to significantly decrease as age increased, while sagittal descent significantly increased with increased age (p = 0.0066).

CONCLUSION

Weightbearing CT has high utility in identification of Lisfranc injuries particularly when comparing injured and uninjured sides, which may be its greatest utility in defining injuries. This is evident in the excellent diagnostic ability of the M2-C1 measurement. By defining baseline anatomic measurements for Lisfranc complex parameters in our patient population, we provide normal parameters for comparison when evaluating potential subtle injuries.

LEVEL OF EVIDENCE

III.

Comparing bilateral feet computed tomography scans can improve surgical decision making for subtle Lisfranc injury

INTRODUCTION

Subtle Lisfranc injuries (SLIs) are challenging to diagnose. Although weightbearing (WB) radiographs have been suggested to identify SLIs, approximately 20% are missed on initial radiographic assessment. Computed tomography (CT) has been suggested as an alternative, but has not provided any diagnostic guideline. Therefore we compared measurement techniques on radiographs and bilateral foot CT scans for the efficiency of diagnosis and making surgical decisions for SLI.

METHODS

We retrospectively investigated patients diagnosed with SLIs between January 2014 and January 2020. Distances between both medial cuneiform and second metatarsal base (C1M2), and the first and second metatarsal bases (M1M2), were measured on bilateral WB radiographs. Bilateral foot CT scans were taken, and the distances between C1M2 were checked on the axial and three points of the coronal plane (top, middle, and base). The surgical indication was > 1 mm of diastasis on CT scan. Clinical outcomes were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) score at final follow-up. Intraobserver and interobserver agreements were assessed.

RESULTS

Thirty patients with SLIs were reviewed. Twenty-four patients underwent surgical fixation (Group A) and six patients were treated conservatively (Group B). The side-to-side difference (STSD) of C1M2 and M1M2 distances greater than 1 mm showed 91.7% and 54.2% sensitivity, and 66.7% and 16.7% specificity, respectively. Investigating STSDs of all points on CT scans were informative to discriminate both groups (P ≤ 0.038). Clinical outcomes showed no significant difference between the groups (P = 0.631). Intraclass and interclass correlation coefficient values showed good to very good reliability, except for STSD of WB M1M2 distance and the coronal top plane.

CONCLUSION

Investigating bilateral foot CT scans was significantly efficient and reliable for the diagnosis and treatment plan for SLI. On radiographs, STSD of WB C1M2 distance was more sensitive than STSD of WB M1M2 distance.

LEVEL OF EVIDENCE

Case control study; III.

Weight-bearing cone-beam CT: the need for standardised acquisition protocols and measurements to fulfill high expectations-a review of the literature

Weight bearing CT (WBCT) of the lower extremity is gaining momentum in evaluation of the foot/ankle and knee. A growing number of international studies use WBCT, which is promising for improving our understanding of anatomy and biomechanics during natural loading of the lower extremity. However, we believe there is risk of excessive enthusiasm for WBCT leading to premature application of the technique, before sufficiently robust protocols are in place e.g. standardised limb positioning and imaging planes, choice of anatomical landmarks and image slices used for individual measurements. Lack of standardisation could limit benefits from introducing WBCT in research and clinical practice because useful imaging information could become obscured. Measurements of bones and joints on WBCT are influenced by joint positioning and magnitude of loading, factors that need to be considered within a 3-D coordinate system. A proportion of WBCT studies examine inter- and intraobserver reproducibility for different radiological measurements in the knee or foot with reproducibility generally reported to be high. However, investigations of test-retest reproducibility are still lacking. Thus, the current ability to evaluate, e.g. the effects of surgery or structural disease progression, is questionable. This paper presents an overview of the relevant literature on WBCT in the lower extremity with an emphasis on factors that may affect measurement reproducibility in the foot/ankle and knee. We discuss the caveats of performing WBCT without consensus on imaging procedures and measurements.

Micro-CT analysis of the Lisfranc complex reveals higher bone mineral density in dorsal compared to plantar regions

Injuries to the Lisfranc complex may require surgical fixation, the stability of which may be correlated with bone mineral density (BMD). However, there is limited research on regional BMD variations in the Lisfranc complex. This study used quantitative micro-CT to characterize regional BMD in the four bones (medial cuneiform, intermediate cuneiform, first metatarsal, and second metatarsal) of this complex. Twenty-four cadaveric specimens were imaged with a calibration phantom using micro-CT. Each bone was segmented and divided into eight regions based on an anatomical coordinate system. BMD for each octant was calculated using scan-specific calibration equations and average image intensity. Differences between regions were analyzed using ANOVA with post hoc analysis and differences between groups of four octants in each plane were analyzed with t-tests with significance level α = 0.05. The highest density region in the medial cuneiform was the distal-dorsal-lateral and dorsal regions showed significantly higher BMD than plantar regions. The intermediate cuneiform had the highest density in the distal-dorsal-medial region and the dorsal and medial regions had higher BMD than the plantar and lateral regions, respectively. The densest region of the first metatarsal was the distal-dorsal-lateral and distal regions had significantly higher BMD than proximal regions. In the second metatarsal, the distal-dorsal-medial region had the highest density, and the distal, dorsal, and medial regions had significantly higher BMD than the proximal, plantar, and lateral regions, respectively. The predominant finding was a pattern of increased density in the dorsal bone regions, which may be relevant in the surgical management of Lisfranc injuries.

Outcome after nonoperative treatment of stable Lisfranc injuries. A prospective cohort study

BACKGROUND

The aim of this study was to evaluate the outcome after nondisplaced and stable Lisfranc injuries.

METHODS

26 patients with injuries to the Lisfranc joint complex detected on CT scans, but without displacement were tested to be stable using a fluoroscopic stress test. The patients were immobilized in a non-weightbearing short leg cast for 6 weeks. The final follow-up was 55 (IQR 53-60) months after injury.

RESULTS

All the Lisfranc injuries were confirmed to be stable on follow-up weightbearing radiographs at a minimum of 3 months after injury. Median American Foot and Ankle Society (AOFAS) midfoot score at 1-year follow-up was 89 (IQR 84-97) and at final follow-up 100 (IQR 90-100); The AOFAS score continued to improve after 1-year (P=.005). The median visual analog scale (VAS) for pain was 0 (IQR 0-0) at the final follow-up. One patient had radiological signs of osteoarthritis at 1-year follow-up.

CONCLUSION

Stable Lisfranc injuries treated nonoperatively had an excellent outcome in this study with a median follow-up of 55 months. The AOFAS score continued to improve after 1 year.

[Short-term effectiveness of Endobutton plate in reconstruction of Lisfranc ligament]

Objective

To observe the short-term effectiveness of Endobutton plate in the reconstruction of Lisfranc ligament in tarsometatarsal joint injury.

Methods

Between March 2015 and July 2018, 18 patients with tarsometatarsal joint injuries were treated with Lisfranc ligament reconstruction by Endobutton plate. There were 12 males and 6 females with an average age of 32.5 years (range, 16-55 years). The causes of injury were traffic accident in 8 cases, falling from height in 3 cases, crushing by a heavy objective in 4 cases, and spraining in 3 cases. There were 10 cases of Myerson type A, 4 of type B1, 2 of type B2, 1 of type C1, and 1 of type C2. The interval between injury and operation ranged from 3 to 9 days (mean, 4.9 days). X-ray examination was performed regularly after operation to measure the distance between the first and the second metatarsal joints, and the visual analogue scale (VAS) score was used to evaluate the pain relief. At last follow-up, the reduction of tarsometatarsal joint was evaluated by measuring and comparing the height of the affected and healthy arches. The foot function was evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS) score.

Results

The average follow-up time was 15.8 months (range, 10-28 months). All incisions healed by first intention. X-ray reexamination showed that there was no screw loosening or plate fracture. There were significant differences in the distance between the first and the second metatarsal joints and VAS score at 3 months after operation, before removal of the internal fixator, and at last follow-up when compared with preoperative values ( P<0.05). There was no significant difference between the time points after operation ( P>0.05). At last follow-up, there was no significant difference in the arch height between affected foot [(5.3±0.2) mm] and healthy foot [(5.4± 0.3) mm] ( t=1.798, P=0.810). The AOFAS score of foot function was 89.5±7.3 with excellent in 12 cases, good in 4 cases, and fair in 2 cases. The excellent and good rate was 88.9%.

Conclusion

The reconstruction of Lisfranc ligament with Endobutton plate can stabilize the tarsometatarsal joint and achieve satisfactory foot function at early stage.