Change in the First Cuneiform-Second Metatarsal Distance After Simulated Ligamentous Lisfranc Injury Evaluated by Weightbearing CT Scans

Augmented Stress Weight-bearing CT for Evaluation of Subtle Lisfranc Injuries in the Elite Athlete

BACKGROUND

Lisfranc injuries refer to a disruption or displacement of the tarsometatarsal joint of the foot. Subtle Lisfranc injuries can go undiagnosed on conventional imaging leading to devastating consequences and poor functional outcomes for elite athletes. Objective. The objective of this case study is to present a novel imaging technique using weight-bearing computed tomography (CT) with enhanced stress to identify subtle, dynamically unstable Lisfranc injuries. We illustrate this with a case presentation of an elite athlete who ultimately required surgical fixation for a subtle Lisfranc injury.

MATERIALS AND METHODS

To perform an augmented stress weight-bearing CT, the patient was positioned standing, with their feet facing forward, and weight equally distributed. The patient was then coached to symmetrically raise both heels from the scanner platform. This plantarflexion provided augmented stress on the midfoot, allowing for more sensitive imaging of the Lisfranc injury. The weight-bearing CT and augmented stress images undergo 3D reconstruction and postprocessing to render coronal and sagittal images, allowing for comparison of the standard weight-bearing and augmented stress images.

RESULTS

We present the case of a 22-year-old collegiate football lineman sustaining a Lisfranc injury. The injury diagnosis was made by magnetic resonance imaging (MRI) and clinical examination, without evidence of injury on weight-bearing XR or standard weight-bearing CT. With augmented stress CT imaging, the Lisfranc instability was noted, leading to surgical fixation, and return to sport the next season.

CONCLUSION

We propose this technique for diagnosing subtle, unstable Lisfranc injuries where clinical suspicion persists despite inconclusive imaging, particularly in elite athletes. Further research is needed with larger sample sizes to investigate the sensitivity of this novel imaging technique for the detection of Lisfranc injury.

LEVELS OF EVIDENCE

Level 4: Case Report.

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.

Weight-Bearing Computed Tomography of the Foot and Ankle-What to Measure?

Weight-bearing computed tomography (WBCT) was introduced in 2012 for foot and ankle applications as a breakthrough technology that enables full weight-bearing, three-dimensional imaging unaffected by x-ray beam projections or foot orientation. The literature describing the use of WBCT in the treatment of foot and ankle disorders is growing, and this article provides an overview of what can be measured with WBCT.

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 Computed Tomography of the Foot and Ankle in the Pediatric Population

BACKGROUND

Newer cone-beam computed tomography (CT) technology has grown in popularity for evaluation of foot and ankle pathology in the weight-bearing (WB) position. Many studies have demonstrated its benefits within the adult population, but there is a paucity of its use within the pediatric literature. The purpose of this study was to describe the indications and clinical findings of WBCT within a pediatric population.

METHODS

A retrospective cohort of 68 patients (86 extremities) who underwent WBCT for a variety of conditions were compared with 48 patients (59 extremities) who underwent traditional supine nonweight-bearing (NWB) CTs. Clinical indications, demographic data, radiation doses, and cost were obtained from the medical record. WBCTs were obtained in a private outpatient orthopaedic clinic, and the conventional NWBCTs were obtained within a hospital-based system.

RESULTS

The most common indications for obtaining a WBCT and NWBCT in our study were fracture, tarsal coalition, and Lisfranc injury. The average WBCT radiation dose was 0.63 mGy for patients <100 lbs and 1.1 mGy for patients >100 lbs undergoing WBCT. For NWBCTs, the average radiation dose was 7.92 mGy for patients <100 lbs and 10.37 mGy for patients greater than 100 lbs. There was a significant reduction in radiation dose for all patients who underwent WBCT (P<0.0001 vs. 0.002). The average reimbursement for NWBCTs was $505 for unilateral studies and $1451 for bilateral studies. The average reimbursement for the WBCTs was $345 for unilateral studies and $635 for bilateral studies.

CONCLUSIONS

WBCT offers a new modality for studying complex foot and ankle pathoanatomy in the pediatric population at a reduced radiation exposure and reduced cost.

LEVEL OF EVIDENCE

Level III-a retrospective comparative study.

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.

Biomechanical Comparison of Fibertape Device Repair Techniques of Ligamentous Lisfranc Injury in a Cadaveric Model

BACKGROUND

Lisfranc ligamentous injuries are complex, and their treatment, along with the preferred method of fixation, is controversial. Implementing a flexible synthetic augmentation device (fibertape) has been described as an alternative to traditional screw fixation. This biomechanical study evaluated two fibertape devices with interference screw fixation: InternalBrace, and InternalBrace with supplementary intercuneiform stabilization.

METHODS

The diastasis and relative angular displacement between bones were measured at three midfoot joints in the Lisfranc articulation. Measurements were obtained for the pre-injured, injured, and post-fixation stages under static loading. Specimens then underwent stepwise increases in cyclic loading performed at 1 Hz and 100 cycles, at 100 N ground reaction force intervals from 500 to 1200 N to simulate postoperative loading, and then up to 1800 N to simulate high loads. Failure of fixation was defined as diastasis greater than 2 millimeters at the second-metatarsal - medial-cuneiform joint.

RESULTS

InternalBrace specimens demonstrated failures in 3 of 9 (33%) specimens at cyclic loads of 1000 N. Conversely, InternalBrace with Supplementary Limb specimens had 1 failure at 1200 N. The difference in diastasis at the second metatarsal-medial cuneiform joint was statistically significant between the two groups at higher loads of 1600N (p = 0.019) and 1800N (p = 0.029).

CONCLUSION

The use of InternalBrace for ligamentous Lisfranc injuries appears to provide a biomechanically viable alternative for withstanding early postoperative protected weight bearing. Furthermore, the use of a supplementary limb in addition to the InternalBrace fibertape fixation method appears to enhance its biomechanical efficacy.

Sports-Related Lisfranc Injuries and Recognition of Lisfranc Variants: Surgical Strategies for Stabilization

Much has changed since Lisfranc described lesions at the tarsometatarsal (TMT) joint in 1815. What was considered an osseous high-energy condition nowadays is understood as myriad possible presentations, occurring in minor and inconspicuous traumas. Advancements in diagnostics of Lisfranc injury allow recognizing many variants of this trauma presentation, most of them with a focus on ligaments. This perception shifted trends in surgical planning, especially for implants and fixation techniques. These revolutions established a new and evolving universe around TMT lesions, different from what was known only a few years ago and still not enough to completely settle the disease scenario.