The diagnostic accuracy of radiographs in Lisfranc injury and the potential value of a craniocaudal projection

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.

Lisfranc Injury Diagnosis: What Is the Diagnostic Reliability of New Radiographic Signs Using Three-dimensional CT?

BACKGROUND

Up to one-third of Lisfranc injuries (an injury affecting the normal stability, alignment, and congruency of the tarsometatarsal joints) are misdiagnosed. Delayed diagnosis and improper treatment may lead to long-term, irreversible sequela and functional disability. Recently, the employment of three-dimensional (3D) CT demonstrated higher diagnostic reliability, but there is limited evidence on this, and radiologic features of Lisfranc injuries when using this diagnostic modality are not well described.

QUESTION/PURPOSE

What is the diagnostic performance of several novel radiographic signs on 3D CT when evaluating for Lisfranc injury, namely the Mercedes sign, the peeking metatarsal sign, and the peeking cuneiform sign, and what is the interobserver and intraobserver reliability of those diagnostic signs?

METHODS

In this retrospective, diagnostic study, video clips of 3D CT reconstructions of 52 feet with intraoperatively confirmed Lisfranc injuries and 50 asymptomatic feet with a normal appearance of the tarsometatarsal joints, as ascertained by a subspecialty-trained foot and ankle surgeon and a musculoskeletal radiologist, were analyzed by two foot and ankle specialists and three orthopaedic residents twice each, with a washout period of 2 weeks. Among the 52 patients with intraoperative evidence of Lisfranc injury, there were 27 male patients and 25 female patients, with a median (IQR) age of 40 years (23 to 58); among the 50 controls, there were 36 male and 14 female patients, with a median age of 38 years (IQR 33 to 49). For each video clip, the presence of all three radiographic signs was documented (each sign was rated in a binary yes/no fashion). Before the evaluations, all observers underwent a short training session by the head of the foot and ankle department. Later, these reading were used to assess for the sensitivity, specificity, and area under the receiver operating characteristic curve in terms of Lisfranc diagnosis against the gold standard of intraoperative testing of tarsometatarsal joint stability. Intraoperatively, the congruency and stability of the second tarsometatarsal joint had been evaluated by direct visualization and by the insertion of a probe into the joint between the base of the second metatarsus and the medial cuneiform and twisting the probe to assess for stability. The individuals evaluating the video clips were unaware of the surgically obtained diagnosis at the time they performed their evaluations.

RESULTS

All 3D radiographic signs that were examined had excellent diagnostic reliability in terms of sensitivity and specificity, ranging from 92% to 97% and from 92% to 93%, respectively. When assessing the association between the suggested 3D radiographic signs and Lisfranc injury diagnosis as a function of the area under the receiver operating characteristic curve, the Mercedes sign demonstrated a higher area under the curve than the other signs did (0.91 versus 0.87 versus 0.8; p < 0.001). The mean intraobserver and interobserver reliability (kappa) values were excellent for all 3D radiographic signs that were evaluated.

CONCLUSION

The proposed radiographic findings demonstrated excellent diagnostic performance and were repeatable within and among observers. Three-dimensional CT radiographic signs could function as a valuable diagnostic tool for the evaluation and initial screening for Lisfranc injury in the acute injury phase because obtaining AP bilateral standing radiographs of the foot is often impractical in the acute setting. Further research and comparison with AP weightbearing radiographs of the bilateral feet may be warranted.

LEVEL OF EVIDENCE

Level III, diagnostic study.

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.

Is the diagnostic validity of conventional radiography for Lisfranc injury acceptable?

BACKGROUND

Lisfranc injuries mainly involve the tarsometatarsal joint complex and are commonly misdiagnosed or missed in clinical settings. Most medical institutions prefer to use conventional radiography. However, existing studies on conventional radiographs in Lisfranc injury lack a large population-based sample, influencing the validity of the results. We aimed to determine the diagnostic validity and reliability of conventional radiography for Lisfranc injury and whether computed tomography can alter clinical decision-making.

METHODS

This retrospective study included 307 patients with, and 100 patients without, Lisfranc injury from January 2017 to December 2019. Diagnosis was confirmed using computed tomography. A senior and junior surgeon independently completed two assessments of the same set of anonymised conventional radiographs at least 3 months apart. The surgeons were then asked to suggest one of two treatment options (surgery or conservative treatment) for each case based on the radiographs and subsequently on the CT images.

RESULTS

All inter- and intra-observer reliabilities were moderate to very good (all κ coefficients > 0.4). The mean (range) true positive rate was 81.8% (73.9%-87.0%), true negative rate was 90.0% (85.0%-94.0%), false positive rate was 10.0% (6.0%-15.0%), false negative rate was 18.2% (13.0%-26.1%), positive predictive value was 96.1% (93.8%-97.8%), negative predictive value was 62.4% (51.5%-69.7%), classification accuracy was 83.8% (76.7%-88.2%), and balanced error rate was 14.1% (10.2%-20.5%). Three-column injuries were most likely to be recognized (mean rate, 92.1%), followed by intermediate-lateral-column injuries (mean rate, 81.5%). Medial-column injuries were relatively difficult to identify (mean rate, 60.7%). The diagnostic rate for non-displaced injuries (mean rate, 76.7%) was lower than that for displaced injuries (mean rate, 95.5%). The typical examples are given. A significant difference between the two surgeons was found in the recognition rate of non-displaced injuries (p = 0.005). The mean alteration rate was 21.9%; the senior surgeon tended to a lower rate (15.6%) than the junior one (28.3%) (p < 0.001).

CONCLUSIONS

The sensitivity, specificity, and classification accuracy of conventional radiographs for Lisfranc injury were 81.8%, 90.0%, and 83.8%, respectively. Three-column or displaced injuries were most likely to be recognized. The possibility of changing the initial treatment decision after subsequently evaluating computed tomography images was 21.9%. The diagnostic and clinical decision-making of surgeons with different experience levels demonstrated some degree of variability. Protected weight-bearing and a further CT scan should be considered if a Lisfranc injury is suspected and conventional radiography is negative.

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.

The role of three dimension computed tomography in Lisfranc injury diagnosis

PURPOSE

To evaluate the intra/inter observer and diagnostic reliability of 3-dimensional (3D) model reconstruction computed tomography (CT) compared to the traditional two-dimensional (2D) CT when evaluating Lisfranc (LF) injuries.

METHODS

A retrospective study was performed on CT studies of patients with clinically suspected LF injuries examined in the emergency department at medium size medical center. Each CT study was evaluated for metatarsal fractures and subluxations employing both standard 2D and 3D CT model reconstruction. Four orthopaedists, 2 senior and 2 residents, were assigned to review and evaluate each CT. Each CT study was reviewed twice by each reader in a randomized order. Descriptive statistics were calculated for all measured variables. The intra-observer and inter-observer agreement Kappa coefficients were calculated to evaluate reliability and reproducibility between and within readers for each modality.

RESULTS

The study included 44 patients. Median age was 41.4 years (interquartile range, 23-58). The intra-observer and inter-observer reliability was good (intra-observer; 3D Kappa; 0.76 and 2D Kappa 0.73 p<0.001, inter-observer; 3D Kappa 0.68, 2D Kappa 0.63 and combined 2D and 3D kappa 0.68, p<0.001). Three dimensional CT was found to be more sensitive than 2D CT, specifically when evaluating for second metatarsal dislocation (sensitivity: 70% vs 47%). Combined evaluation of 2D and 3D CT, greatly improved sensitivity rate to 85.7%. In terms of fracture diagnosis, combined evaluation of 2D and 3D CT showed higher sensitivity and specificity rates as compared to 2D or 3D alone.

CONCLUSION

The employment of 3D CT in LF injury diagnosis, in isolation and in combination with 2D CT, seems to improve the diagnostic accuracy and reliability between and within observers compared to 2D CT alone.

Deep Learning Algorithms Improve the Detection of Subtle Lisfranc Malalignments on Weightbearing Radiographs

BACKGROUND

Detection of Lisfranc malalignment leading to the instability of the joint, particularly in subtle cases, has been a concern for foot and ankle care providers. X-ray radiographs are the mainstay in the diagnosis of these injuries; thus, improving the performance of clinicians in interpreting radiographs can noticeably affect the quality of health care in these patients. Here we assessed the performance of deep learning algorithms on weightbearing radiographs for detection of Lisfranc joint malalignment in patients with Lisfranc instability.

METHODS

In a retrospective study, 640 patients with Lisfranc malalignment leading to instability were recruited plus 640 individuals with uninjured feet and healthy Lisfranc joint as the control group. All radiographs were screened by orthopaedic surgeons. Two deep learning models were trained, validated, and tested (in a ratio 80:10:10) using a single-view (anteroposterior) and 3-view (anteroposterior, lateral, oblique) radiographs. The performances of the models were reported as sensitivity, specificity, positive and negative predictive values, accuracy, F score, and area under the curve (AUC).

RESULTS

No significant differences were observed between the patients and the controls regarding age, gender, race, and body mass index. The best deep learning algorithm outperformed our human interpreters (<1% vs ~10% misdiagnosis), 94.8% sensitivity, 96.9% specificity, 98.6% accuracy, 95.8% F score, and 99.4% AUC.

CONCLUSION

Deep learning methods have shown promising potential in acting as an assistant interpreter of radiographic images in patients with Lisfranc malalignment. Developing these algorithms can hasten and improve the accuracy of diagnosis and reduce further costs and burdens on the patients and health care system.

LEVEL OF EVIDENCE

Level III, case-control Machine Learning study.

Lisfranc injury: Refined diagnostic methodology using weightbearing and non-weightbearing radiographs

BACKGROUND

To compare diagnostic parameters for Lisfranc instability on WB and NWB radiographs and to assess the inter-observer reliability of a standardized diagnostic protocol.

PATIENTS AND METHODS

Patients who had undergone surgical treatment for subtle, purely ligamentous Lisfranc injury with both WB and NWB post-injury, pre-surgery films (n = 26) were included in this multicentre, retrospective comparative study. Also included was a control group (n = 26) of patients with isolated fifth metatarsal avulsion fractures who similarly had both WB and NWB films. Multiple midfoot distance and alignment measurements were used to evaluate the Lisfranc joint on both WB and NWB views. To evaluate interobserver reliability, measurements were made by two independent observers across a cohort subset.

RESULTS

When comparing the NWB views between groups, only C1M2 (medial cuneiform- second metatarsal) distance was found to be significantly larger (∆ = 1.35 mm, p <0.001) for Lisfranc injuries. Most notably, C2M2 (Intermediate cuneiform - second metatarsal) step off-caused by lateral translation of the second metatarsal base-was not significantly different (∆ = 0.39 mm, p = 0.101) between Lisfranc patients and controls. On WB views, Lisfranc patients had significantly larger changes to C1M2 distance and C2M2 step-off as compared to controls (∆ = 2.97 mm, p <0.001 and ∆ =  1.98 mm, p <0.001 respectively). M1M2 (first to second intermetatarsal) distance was not significantly different between patients and controls in WB films. Within the cohort of ligamentous Lisfranc patients, C1M2 distance and C2M2 step-off were significantly larger in WB when compared to NWB films (∆ =  1.77 mm, p <0.001 and ∆ =  1.58 mm, p <0.001 respectively). For these parameters, inter-observer reliability scores (ICC) of >0. 90 were found when interpreting WB radiographs and ICC's ranging between 0.61 and 0.80 were found when interpreting NWB radiographs.

CONCLUSION

Using WB imaging for diagnosing subtle Lisfranc instability reveals larger diastasis in the tarsometatarsal joint and has a higher interobserver reliability compared to NWB imaging. Clinical concern for subtle or occult Lisfranc instability in any patient should therefore trigger WB radiographic assessment since such injuries may be missed on NWB views.

Reliability of various diastasis measurement methods on weightbearing radiographs in patients with subtle Lisfranc injuries

OBJECTIVE

This study aimed to evaluate the reliability of the diastasis measurements between the medial cuneiform and the second metatarsal on weightbearing radiography.

MATERIALS AND METHODS

We retrospectively examined 18 patients who underwent open surgery for subtle Lisfranc injuries. Preoperative weightbearing radiography of the affected and unaffected feet was evaluated in all patients. The diastasis between the medial cuneiform and the second metatarsal was measured in both feet using the following four methods: diastasis between parallel lines, distal point diastasis, middle point diastasis, and proximal point diastasis. Intraclass correlation coefficients with consistency of agreement were calculated to evaluate inter- and intraobserver reliability.

RESULTS

The intra- and interobserver reliabilities of all four methods were good. Intraclass correlation coefficients for intraobserver reliability ranged from 0.87 to 0.93. Those for interobserver reliability ranged from 0.81 to 0.91.

CONCLUSIONS

The reliabilities of the diastasis measurement methods between the medial cuneiform and the second metatarsal on weightbearing radiography were good. Measuring the diastasis between the medial cuneiform and the second metatarsal on weightbearing radiography is useful in evaluating subtle injuries when uniform measurement methods are used.

The Diagnostic Accuracy of MRI to Evaluate Acute Lisfranc Joint Injuries: Comparison With Direct Operative Observations

Background:

Early diagnosis is important in patients with Lisfranc joint injury to avoid subsequent complications. As the ligaments in the Lisfranc joint are relatively small and course obliquely, isotropic 3-dimensional (3D) magnetic resonance imaging (MRI) can be beneficial to evaluate ligament injury. The purpose of this study was to investigate the diagnostic accuracy of MRI, including isotropic 3D MRI for acute injury of the Lisfranc joint, especially of the interosseous C1-M2 ligament (Lisfranc ligament), the dorsal C1-M2 ligament (dorsal ligament), and the interosseous C1-C2 ligament, compared with direct operative observations.

Methods:

This retrospective review identified 27 patients who had undergone MR examination for acute Lisfranc joint injury followed by surgery. We reviewed the operative reports that described the Lisfranc, dorsal, and interosseous C1-C2 ligaments. All patients underwent an MRI, including a 2D oblique plane image parallel to the Lisfranc ligament and an isotropic 3D MRI. An image analysis of the integrity of the 3 ligaments and other associated injuries was performed. The diagnostic accuracy of MRI was analyzed using operative findings as a reference standard.

Results:

Lisfranc and dorsal ligament injuries were identified on MRI in all patients. MRI depicted disruption of the interosseous C1-C2 ligament in 12 patients. MRI diagnostic accuracy for detection of Lisfranc, dorsal, and interosseous C1-C2 ligaments was 100% (95% CI 0.82-1.0), 74% (95% CI 0.54-0.89), and 70% (95% CI 0.50-0.86), respectively.

Conclusion:

MRI with oblique planes parallel to the Lisfranc ligament and isotropic 3D MRI was reliable for detecting Lisfranc ligament injury, whereas MRI findings of the dorsal and interosseous C1-C2 ligaments were less consistent with operative observations.

Level of Evidence:

Level IV, case series.

Computational analysis of the clinical presentation of a ligamentous Lisfranc injury

Lisfranc injuries in the midfoot disrupt key arches of the foot which, if left untreated, can progress to pain, dysfunction, and arthritis. A clinical challenge is that 30-40% of Lisfranc injuries are missed in initial evaluations. The objective of this study was to explore different conditions of limb loading that could influence the biomechanics of the Lisfranc joint in a validated computational model. A computational model was created using SolidWorks software to represent the bones and soft tissues of the lower leg and foot. The model was compared to a cadaveric study of healthy and injured Lisfranc joints. The model was then used to simulate weight-bearing radiographs and evaluate how muscle activity and foot position impacted the diastasis of the Lisfranc joint, a key indicator used to diagnose Lisfranc injuries. The computational model was within one standard deviation of the cadaveric study in all measurements for the healthy and injured foot. When simulating weight-bearing radiographs, the presence of muscle activity or inversion/eversion resulted in less joint separation for the model with ligamentous Lisfranc injuries. While previous research has noted that weight-bearing radiographs provide better conditions to assess Lisfranc injuries than nonweight-bearing, this study suggests that in weight-bearing radiographs both altering the position of the foot, possibly due to pain, and the active contraction of the extrinsic flexor muscles can obfuscate indications of a Lisfranc injury.

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

Weightbearing CT (WBCT) allows evaluation of the Lisfranc joint under physiologic load. We compared the diagnostic sensitivities of one-dimensional (1D) distance, two-dimensional (2D) area, and three-dimensional (3D) volumetric measurement of the injured Lisfranc joint complex (tarsometatarsal, intertarsal, and intermetatarsal) on WBCT among patients with surgically-confirmed Lisfranc instability. The experimental group comprised of 14 patients having unilateral Lisfranc instability requiring operative fixation who underwent preoperative bilateral foot and ankle WBCT. The control group included 36 patients without foot injury who underwent similar imaging. Measurements performed on WBCT images included: (1) Lisfranc joint (medial cuneiform-base of second metatarsal) area, (2) C1-C2 intercuneiform area, (3) C1-M2 distance, (4) C1-C2 distance, (5) M1-M2 distance, (6) first tarsometatarsal (TMT1) angular alignment, (7) second tarsometatarsal (TMT2) angular alignment, (8) TMT1 dorsal step off distance, and (9) TMT2 dorsal step-off distance. In addition, the volume of the Lisfranc joint in the coronal and axial plane were calculated. Among patients with unilateral Lisfranc instability, all WBCT measurements were increased on the injured side as compared to the contralateral uninjured side (p values:  <.001-.008). Volumetric measurements in the coronal and axial plane had a higher sensitivity (92.3%; 91.6%, respectively) and specificity (97.7%; 96.5%, respectively) than 2D and 1D Lisfranc joint measurements, suggesting them to be the most accurate in diagnosing Lisfranc instability. The control group showed no difference in any of the measurements between the two sides. WBCT scan can effectively differentiate between stable and unstable Lisfranc injuries. Lisfranc joint volume measurements demonstrate high sensitivity and specificity, suggesting that this new assessment has high clinical implications for diagnosing subtle Lisfranc instability.

Isolated Medial Cuneiform Fractures: A Systematic Search and Qualitative Analysis of Case Studies

BACKGROUND

Isolated medial cuneiform fracture is a rare but diagnostically challenging condition. Diagnostic delay in these cases may lead to delays in ideal treatment approaches and prolonged symptoms. An understanding of clinical presentation is needed to expedite diagnosis, facilitate decision making, and guide treatment approach.

METHODS

Case studies/series were searched in four databases until September 2019. Included studies had participants with a history of traumatic closed medial cuneiform fracture. Studies were excluded if the medial cuneiform fractures were open fractures, associated with multitrauma, or associated with dislocation/Lisfranc injury. Three blinded reviewers assessed the methodological quality of the studies, and a qualitative synthesis was performed.

RESULTS

Ten studies comprising 15 patients were identified. Mean ± SD patient age was 38.0 ± 12.8 years, with 86.7% of reported participants being men. The overall methodological quality was moderate to high, and reporting of the patient selection criteria was poor overall. The most commonly reported clinical symptoms were localized tenderness (60.0%) and edema (53.3%). Direct blow was the most common inciting trauma (46.2%), followed by axial load (30.8%) and avulsion injuries (23.1%). Baseline radiographs were occult in 72.7% of patients; magnetic resonance imaging and computed tomography were the most common diagnostic modalities. Mean ± SD diagnostic delay was 64.7 ± 89.6 days. Conservative management was pursued in 54.5% of patients, with reported resolution of symptoms in 3 to 6 months. Surgical intervention occurred in 45.5% of patients and resulted in functional restoration in 3 to 6 months in all but one patient.

CONCLUSIONS

Initial radiographs for isolated medial cuneiform fractures are frequently occult. Due to expedience and relatively low cost, radiographs are still a viable first-line imaging modality. If clinical concern remains, magnetic resonance imaging may be pursued to minimize diagnostic delay. Conservative management is a viable treatment method, with expected return to full function in 3 to 6 months.

Reliability of measurements assessing the Lisfranc joint using weightbearing computed tomography imaging

INTRODUCTION

Subtle Lisfranc joint injuries remain challenging to diagnose in clinical practice. Although of questionable accuracy, bilateral weightbearing radiographs are considered the current gold standard to assess these injuries. However, weightbearing computed tomography (WBCT), which provides clearer visualization of bony landmarks, can also be used for evaluation. This study aims to design a protocol that reliably measures the distance between the medial cuneiform (C1) and second metatarsal (M2) to assess the Lisfranc joint using WBCT imaging.

METHODS

Two unique methods of measuring the C1-M2 distance were designed that localize the center of the interosseous Lisfranc ligament (ILL, reference point). This reference point was located by (I) measuring a specific distance at the M2 base, or (II) approximating from nearby bony landmarks, on both axial (Ax) and coronal (Cor) WBCT images. Four parameters (I-Ax, I-Cor, II-Ax, and II-Cor) were evaluated for each of 96 specimens. Measurements were recorded by three independent observers and repeated for inter- and intra-observer agreement.

RESULTS

In total, 96 patient image series were included and assessed in our study with an average age of 46 (19-66, SD 16.1) and average BMI of 25.8 (17.8-30.5, SD 4.3). I-Ax showed excellent agreement for intra-observer evaluation (R = 0.802) and good agreement for inter-observer evaluation (R = 0.727). I-Cor demonstrated excellent inter- (R = 0.814) and intra-observer (R = 0.840) agreement. Good agreement was found for both II-Ax and II-Cor for both intra- (R = 0.730, R = 0.708) and inter-observer (R = 0.705, R = 0.645) evaluation.

CONCLUSION

Measuring the C1-M2 joint space with coronal WBCT imaging through a protocol that localizes the ILL is reproducible, simple, and can potentially be utilized clinically to evaluate the Lisfranc joint.

Lisfranc injury: A review and simplified treatment algorithm

BACKGROUND

Lisfranc injuries encompass large spectrum of injuries varying from low energy to high energy complex fracture dislocations. Whilst multiple complex classification systems exist; these do little to aid and direct the clinical management of patients. Therefore, this study aims to provide a simplified treatment algorithm allowing clinicians to standardise care of Lisfranc injuries.

METHODS

A comprehensive literature search was performed, and abstracts were reviewed to identify relevant literature.

RESULTS

Delay in diagnosis has a negative impact on outcome. If a Lisfranc injury is suspected and plain radiographs are inconclusive; computed tomography and if necessary magnetic resonance imaging are indicated if there is still an index of suspicion. In the absence of joint dislocation/subluxation management will be determined by stability which can be best assessed by weightbearing radiographs. If stable, injuries can be treated conservatively in a non-weight bearing cast for 6 weeks followed by a period of graduated weight bearing. Evidence is mounting that with regard to unstable purely ligamentous Lisfranc injuries primary arthrodesis (PA) has: better functional outcomes, increased cost effectiveness and reduced rates of return to theatre. With regard to bony unstable Lisfranc injuries more research is required before a single treatment modality - PA or open reduction internal fixation can be advocated, due to the lack of randomized control trials and limited patient follow-up periods in existing studies.

CONCLUSION

A simplified treatment algorithm excluding the requirement for complex classifications is suggested. This may help with the diagnosis and management of these injuries. It is our believe that this algorithm will aid health professionals to standardize care for these injuries. Further prospective research trials are required to assess outcomes of different modalities of operative management, particularly with regards to open reduction and internal fixation versus primary arthrodesis for bony Lisfranc injuries.

LEVEL OF EVIDENCE

Level 5.

Radiographic Value of the Lisfranc Diastasis in a Standardized Population

Introduction. Injury to the Lisfranc's joint, in particular to the second metatarsal-medial cuneiform (second MMC) joint, can be difficult to evaluate, especially in subtle Lisfranc injuries. The purpose of this study was to determine the value of the Lisfranc joint width (diastasis) of the adult foot in a standardized population thereby establishing a potential reference range when investigating this area for potential injury. Methods. The 2nd MMC joint in 50 men and 50 women was evaluated. Individuals with a history of foot/ankle pain, previous foot/ankle operation or fracture, or a history of systemic disease were excluded from the study. Bilateral weightbearing digital anterior-posterior and lateral radiographs were taken using a standardized method. Results. The mean 2nd MMC diastasis in 200 feet was 5.6 mm (95% CI 5.39-5.81). In the female population, the mean 2nd MMC diastasis was 5.8 mm (95% CI 5.51-6.09) as compared with 5.6 mm (95% CI 5.31-5.89) in males. The mean distance between the fifth metatarsal base and first cuneiform in the entire study population was 16.3 mm (95% CI 15.57-17.03). Conclusion. This study helps define baseline measurements of the Lisfranc joint for the general population, which can provide a standard measurement against which suspected foot injuries can be compared.Level of Evidence: Level IV.

How to Identify Unstable Lisfranc Injuries? Review of Diagnostic Strategies and Algorithm Proposal

"Misdiagnosed Lisfranc injuries can be as high as 50%, leading to chronic pain, functional impairment, and posttraumatic arthritis. Subtle or incomplete lesions are the most problematic group for an adequate diagnosis. Conventional non-weight-bearing radiographs can overlook up to 30% of unstable cases. Abduction stress radiographs and anteroposterior monopodial comparative weight-bearing radiographic views are very useful to identify instability. Computed tomography gives detailed information about fracture patterns and comminution. MRI can predict instability but it is expensive and not readily available in the acute setting."

Comparative assessment of midfoot osteoarthritis diagnostic sensitivity using weightbearing computed tomography vs weightbearing plain radiography

PURPOSE

Accuracy in diagnosing osteoarthritis in the midfoot using weightbearing plain radiography (WBPR) remains questionable due to the overlapping osseous architecture present, occluding visualization. Weightbearing computed tomography (WBCT), providing clearer bony landmark identification and joint space visualization, can also be used for evaluation. The aim of this project is to perform a standardized retrospective intra-patient analysis identifying the discrepancy of midfoot osteoarthritis diagnosis and osteoarthritis severity grading between WBPR and WBCT.

METHODS AND MATERIALS

A cohort of 302 patient feet was acquired from an internal, consecutive patient database using detailed inclusion criteria. The musculoskeletal radiologist interpretation of the WBCT and WBPR of each specimen was then assessed for any direct diagnosis or mention of osteoarthritic signs in specific articulations of 3 midfoot joint groups (Chopart, "central", and tarsometatarsal). WBPR sensitivity and specificity metrics were calculated with WBCT considered the gold standard for comparison.

RESULTS

From the WBPR radiologist interpretation, we found diagnostic sensitivity of 72.5 % and specificity of 87.9 % for Chopart joints; 61.5 % sensitivity, and 96.1 % specificity for central joints; and 68.4 % sensitivity, and 92.9 % specificity for tarsometatarsal joints. The severity of degenerative changes was also consistently underestimated when interpreted from WBPR relative to WBCT.

CONCLUSIONS

In this series, midfoot osteoarthritis was often undetected on WBPR. WBCT imaging facilitates an earlier, more reliable diagnosis and grading of midfoot osteoarthritis relative to WBPR.

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

BACKGROUND

This study aimed to investigate the widening between the first cuneiform (C1) and second metatarsal (M2) in a Lisfranc ligamentous complex (LLC) joint injury model subjected to successive ligament dissections evaluated by weightbearing computed tomography (CT) scans.

METHODS

Twenty-four intact cadaveric feet served as the control (condition 1). Each component of the LLC (dorsal, interosseous, and plantar ligaments-conditions 2, 3, and 4, respectively) were then sequentially dissected. The specimens were equally randomized to 1 of 3 additional dissections (first or second tarsometatarsal [TMT] joint capsule or first-second intercuneiform ligament [ICL]-conditions 5a, 5b, and 5c, respectively). One additional ligament was then randomly transected (eg, condition 6ac-transection of the first TMT capsule and ICL). Finally, the remaining ligament was transected (condition 7). After each dissection, CT scans were acquired under nonweightbearing (NWB, 0 kg), partial-weightbearing (PWB, 40 kg), and full-weightbearing (FWB, 80 kg) conditions. The distance between the lateral border of C1 and the medial border of M2 was assessed to evaluate diastasis. Linear regressions with 95% CIs and converted q values were used to compare the measured data.

RESULTS

No significant differences were found within the control. In condition 4, an average axial plane widening relative to control of 1.6 mm (95% CI, 1.5-1.8) and 2.1 mm (95% CI, 1.9-2.2) was observed under PWB and FWB. A coronal plane widening of 1.5 mm (95% CI, 1.3-1.6) and 1.9 mm (95% CI, 1.7-2.1) under PWB and FWB, respectively, was measured. A 95% CI of at least a 2-mm widening during PWB was demonstrated in 5c, 6ac, 6bc, and 7.

CONCLUSIONS

Weightbearing computed tomography (WBCT) scans were used to detect ligamentous Lisfranc injuries in a cadaveric model. Relative axial widening greater than 1.5 mm under PWB conditions could indicate a complete LLC injury. Complete transection of the intercuneiform 1-2 ligament was required to detect a 2-mm widening in the nonweightbearing condition.

CLINICAL RELEVANCE

This study provides insight on the detection of various severities of LLC injuries using WBCT imaging.

Review and optimisation of foot radiography technique

INTRODUCTION

Radiography is an important tool in the diagnosis of trauma and diseases of the foot. Consistent image quality and anatomical appearances are essential to ensure that images are interpreted correctly and this study aims to evaluate current technique and use anthropomorphical phantoms in order to investigate the most optimal radiographic technique.

METHODS

A two part study was conducted. An electronic survey was administered in order to ascertain the current radiographic technique utilised within the United Kingdom (UK) National Health Service (NHS) and compare this with techniques published within radiographic positioning textbooks in common use within the UK. A phantom experiment also sought to identify the most appropriate angulation of the central beam to employ in order to optimally visualise the anatomy for standard non-trauma radiography of the foot. A relative visual grading analysis technique was used to assess radiographic quality.

RESULTS

The electronic survey was completed by 38% of departments (n = 69/182) and demonstrated wide inconsistencies in projections, centring points and beam angulations employed across the NHS. The most commonly employed techniques no longer match the majority of positions described in textbooks. The phantom experiment modelled the ability to accurately visualise anatomy with a variation of the central beam angulation. The results demonstrated that the most commonly described textbook techniques remain the most optimal for accurately visualising the anatomy of the foot.

CONCLUSION

This study has validated the radiographic techniques of the foot described in many of the key texts, however self-reported current practice has diverged from this textbook description.

IMPLICATIONS FOR PRACTICE

Reinforcement of fundamental principles will benefit the patient with increased image quality, improved diagnosis and improved consistency of images, particularly when patient care is transferred between centres.

ACR Appropriateness Criteria® Acute Trauma to the Foot

Acute injuries to the foot are frequently encountered in the emergency room and in general practice settings. This publication defines best practices for imaging evaluations for several variants of patients presenting with acute foot trauma. The variants include scenarios when the Ottawa rules can be evaluated, when there are exclusionary criteria, and when suspected pathology is in anatomic areas not addressed by the Ottawa rules. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Imaging in Lisfranc injury: a systematic literature review

OBJECTIVES

To systematically review current diagnostic imaging options for assessment of the Lisfranc joint.

MATERIALS AND METHODS

PubMed and ScienceDirect were systematically searched. Thirty articles were subdivided by imaging modality: conventional radiography (17 articles), ultrasonography (six articles), computed tomography (CT) (four articles), and magnetic resonance imaging (MRI) (11 articles). Some articles discussed multiple modalities. The following data were extracted: imaging modality, measurement methods, participant number, sensitivity, specificity, and measurement technique accuracy. Methodological quality was assessed by the QUADAS-2 tool.

RESULTS

Conventional radiography commonly assesses Lisfranc injuries by evaluating the distance between either the first and second metatarsal base (M1-M2) or the medial cuneiform and second metatarsal base (C1-M2) and the congruence between each metatarsal base and its connecting tarsal bone. For ultrasonography, C1-M2 distance and dorsal Lisfranc ligament (DLL) length and thickness are evaluated. CT clarifies tarsometatarsal (TMT) joint alignment and occult fractures obscured on radiographs. Most MRI studies assessed Lisfranc ligament integrity. Overall, included studies show low bias for all domains except patient selection and are applicable to daily practice.

CONCLUSIONS

While conventional radiography can demonstrate frank diastasis at the TMT joints; applying weightbearing can improve the viewer's capacity to detect subtle Lisfranc injury by radiography. Although ultrasonography can evaluate the DLL, its accuracy for diagnosing Lisfranc instability remains unproven. CT is more beneficial than radiography for detecting non-displaced fractures and minimal osseous subluxation. MRI is clearly the best for detecting ligament abnormalities; however, its utility for detecting subtle Lisfranc instability needs further investigation. Overall, the available studies' methodological quality was satisfactory.

Inter- and intraobserver reliability of non-weight-bearing foot radiographs compared with CT in Lisfranc injuries

BACKGROUND

Injury of the tarsometatarsal (TMT) joint complex, known as Lisfranc injury, covers a wide range of injuries from subtle ligamentous injuries to severely displaced crush injuries. Although it is known that these injuries are commonly missed, the literature on the accuracy of the diagnostics is limited. The diagnostic accuracy of non-weight-bearing radiography (inter- or intraobserver reliability), however, has not previously been assessed among patients with Lisfranc injury.

METHODS

One hundred sets of foot radiographs acquired due to acute foot injury were collected and anonymised. The diagnosis of these patients was confirmed with a CT scan. In one-third of the radiographs, there was no Lisfranc injury; in one-third, a nondisplaced (< 2 mm) injury; and in one-third, a displaced injury. The radiographs were assessed independently by three senior orthopaedic surgeons and three orthopaedic surgery residents.

RESULTS

Fleiss kappa (κ) coefficient for interobserver reliability resulted in moderate correlation κ = 0.50 (95% CI: 0.45- 0.55) (first evaluation) and κ = 0.58 (95% CI: 0.52-0.63) (second evaluation). After three months, the evaluation was repeated and the Cohen's kappa (κ) coefficient for intraobserver reliability showed substantial correlation κ = 0.71 (from 0.64 to 0.85). The mean (range) sensitivity was 76.1% (60.6-92.4) and specificity was 85.3% (52.9-100). The sensitivity of subtle injuries was lower than severe injuries (65.4% vs 87.1% p = 0.003).

CONCLUSIONS

Diagnosis of Lisfranc injury based on non-weight-bearing radiographs has moderate agreement between observers and substantial agreement between the same observer in different moments. A substantial number (24%) of injuries are missed if only non-weight-bearing radiographs are used. Nondisplaced injuries were more commonly missed than displaced injuries, and therefore, special caution should be used when the clinical signs are subtle.

LEVEL OF EVIDENCE

III.

Lisfranc fracture-dislocations: current management

It is essential to know and understand the anatomy of the tarsometatarsal (TMT) joint (Lisfranc joint) to achieve a correct diagnosis and proper treatment of the injuries that occur at that level.

Up to 20% of Lisfranc fracture-dislocations go unnoticed or are diagnosed late, especially low-energy injuries or purely ligamentous injuries. Severe sequelae such as post-traumatic osteoarthritis and foot deformities can create serious disability.

We must be attentive to the clinical and radiological signs of an injury to the Lisfranc joint and expand the study with weight-bearing radiographs or computed tomography (CT) scans.

Only in stable lesions and in those without displacement is conservative treatment indicated, along with immobilisation and initial avoidance of weight-bearing.

Through surgical treatment we seek to achieve two objectives: optimal anatomical reduction, a factor that directly influences the results; and the stability of the first, second and third cuneiform-metatarsal joints.

There are three main controversies regarding the surgical treatment of Lisfranc injuries: osteosynthesis versus primary arthrodesis; transarticular screws versus dorsal plates; and the most appropriate surgical approach.

The surgical treatment we prefer is open reduction and internal fixation (ORIF) with transarticular screws or with dorsal plates in cases of comminution of metatarsals or cuneiform bones.

Cite this article: EFORT Open Rev 2019;4:430-444. DOI: 10.1302/2058-5241.4.180076

Imaging in Foot and Ankle Instability

This article reviews the imaging aspects relevant to ligamentous instabilities of the foot and ankle with a focus on MRI and ultrasound imaging. A pictorial review of the anatomy of the medial and lateral ankle ligaments, syndesmosis, spring ligament, Lisfranc complex, hallux sesamoid complex, and lesser toe plantar plate as seen on MRI is presented. Selected cases of ligamentous pathology relevant to foot and ankle instability are presented. The value of imaging in the assessment of foot and ankle instability is reviewed.

Magnetic resonance imaging of the Lisfranc ligament

Background

The Lisfranc joint has complex structures, and articular surfaces overlap on conventional X-ray radiographs. Hence, there is no available auxiliary examination for diagnosing related injuries. At present, few studies on the imaging of Lisfranc ligaments have been reported, and related imaging data are rare. Therefore, no imaging reference can be used for related diagnosis and repair operations. This study aims to observe and describe the morphology and structure of Lisfranc ligaments using magnetic resonance imaging (MRI), in order to provide imaging reference for the diagnosis and repair of Lisfranc joint injuries.

Methods

MRI scanning was performed on 60 sides of normal feet of 30 healthy adult volunteers. In the MRI scanning on the Lisfranc joint, sagittal scanning was focused on the area between the lateral margin and medial margin of the Lisfranc joint, while oblique coronal scanning was focused on the area parallel to the Lisfranc joint clearance. After acquisition of MRI images, data were burned into a CD, and the morphology and structure of the Lisfranc ligament on the MRI image were observed and described. Hence, the imaging parameters of the Lisfranc ligament were acquired, providing an imaging reference for the diagnosis and repair of Lisfranc joint injuries.

Results

By observing the obtained images of the Lisfranc ligament through appropriate MRI scanning, it was found that the Lisfranc ligament originates at the site 12.63 ± 1.20 mm from the lateral side of the base of the medial cuneiform bone, with a length of 8.02 ± 1.5 mm, a width of 2.53 ± 0.61 mm, a height of 6.96 ± 1.01 mm, forms an included angle of 46.79 ± 3.47° with the long axis of the first metatarsal bone, and finally ends at the base of the second phalanx. Detailed imaging parameters of the Lisfranc joint and ligament were obtained from the present imaging experiment, providing an imaging reference for the diagnosis and repair of Lisfranc joint injuries.

Conclusions

On the MRI images, the sagittal section can clearly display the corresponding situation of the Lisfranc joint bone and longitudinal arch of the foot, tolerably display the Lisfranc joint dorsal ligaments and metatarsal ligaments, and poorly display the Lisfranc ligament. The oblique coronal section can clearly display the transverse arch of the foot and clearly display the cross-section of the Lisfranc ligament. The oblique crosssection can clearly display the horizontal arch of the Lisfranc joint and more clearly display its surrounding ligaments and tendons, especially the entire Lisfranc ligament and its attachment points. This is an important section for the diagnosis of Lisfranc ligament injuries. This study provides a certain imaging reference for the MRI scanning, diagnosis, and repair of Lisfranc joint injuries. Further research with large sample size is still needed to confirm the conclusions.

Lisfranc injuries

Lisfranc injuries are commonly asked about in FRCS Orthopaedic trauma vivas. The term "Lisfranc injury" strictly refers to an injury where one or more of the metatarsals are displaced from the tarsus. The term is more commonly used to describe an injury to the midfoot centred on the 2nd tarsometatarsal joint. The injury is named after Jacques Lisfranc de St. Martin (1790-1847), a French surgeon and gynaecologist who first described the injury in 1815. 'Lisfranc injury' encompasses a broad spectrum of injuries, which can be purely ligamentous or involve the osseous and articular structures. They are often difficult to diagnose and treat, but if not detected and appropriately managed they can cause long-term disability. This review outlines the anatomy, epidemiology, classification, investigation and current evidence on management of this injury.

Lisfranc injuries: an update

Lisfranc injuries are a spectrum of injuries to the tarsometatarsal joint complex of the midfoot. These range from subtle ligamentous sprains, often seen in athletes, to fracture dislocations seen in high-energy injuries. Accurate and early diagnosis is important to optimise treatment and minimise long-term disability, but unfortunately, this is a frequently missed injury. Undisplaced injuries have excellent outcomes with non-operative treatment. Displaced injuries have worse outcomes and require anatomical reduction and internal fixation for the best outcome. Although evidence to date supports the use of screw fixation, plate fixation may avoid further articular joint damage and may have benefits. Recent evidence supports the use of limited arthrodesis in more complex injuries.