MRI of injuries to the first interosseous cuneometatarsal (Lisfranc) ligament

Inconsistent radiographic diagnostic criteria for lisfranc injuries: a systematic review

PURPOSE

To evaluate the radiographic diagnostic criteria and propose standardised radiographic criteria for Lisfranc injuries.

METHODS

A systematic review of the PubMed and Embase databases was performed according to the PRISMA guidelines. The various radiographic criteria for the diagnosis of Lisfranc injuries were extracted. Descriptive statistics were presented for all continuous (as mean ± standard deviation) and categorical variables (as frequencies by percentages).

RESULTS

The literature search included 29 studies that totalled 1115 Lisfranc injuries. The risk of bias ranged from "Low" to "Moderate" risk according to the ROBINS-I tool. The overall recommendations according to the GRADE assessment ranged from "Very Low" to "High". 1st metatarsal to 2nd metatarsal diastasis was the most common of the 12 various radiographic diagnostic criteria observed, as was employed in 18 studies. This was followed by 2nd cuneiform to 2nd metatarsal subluxation, as was employed in 11 studies.

CONCLUSION

The radiographic diagnostic criteria of Lisfranc injuries were heterogeneous. The proposition for homogenous radiographic diagnostic criteria is that the following features must be observed for the diagnosis of Lisfranc injuries: 1st metatarsal to 2nd metatarsal diastasis of ≥ 2 mm on anteroposterior view or 2nd cuneiform to 2nd metatarsal subluxation on anteroposterior or oblique views. Further advanced imaging by CT or MRI may be required in patients with normal radiographs but with continued suspicion for Lisfranc injuries.

LEVEL OF EVIDENCE

4, systematic review.

Imaging of Acute Ankle and Foot Sprains

Ankle and foot injuries are very common injuries in the general population, and more so in athletes. MR imaging is the optimal modality to evaluate for ligamentous injuries of the ankle and associated conditions after ankle sprain. In this article, the authors discuss the epidemiology, biomechanics, normal anatomy, and pathology of the ankle as well as injuries of the hindfoot and midfoot that are often associated with ankle injuries.

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.

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.

Impact of the Subtle Lisfranc Injury on Foot Structure and Function

BACKGROUND

The subtle Lisfranc injury is the disruption of the osteoligamentary complex between the first cuneiform and the second metatarsal, resulting in minor widening of this space that is often difficult to detect with plain radiographs. In this study, we assessed the results after treatment of the different stages of subtle Lisfranc injuries, focusing on their impact on foot arch anatomy and functionality at short- to midterm follow-up.

METHODS

A retrospective study including patients treated in our center for a subtle Lisfranc injury between 2012 and 2019 was conducted. Demographic, epidemiologic, radiographic, and clinical data were obtained and assessed, focusing on foot arch structure and foot function, which was evaluated with the American Orthopaedic Foot & Ankle Society (AOFAS) midfoot score and the Foot Function Index (FFI).

RESULTS

A total of 42 patients with a mean age of 49 ± 17.5 years were included, with an average of 4.3 years' follow-up (range, 1-8). Stage I injuries according to Nunley classification represented 19% and were treated conservatively. Stage II (66.7%) and stage III (14.3%) injuries were treated operatively, via osteosynthesis with screws (74%), K-wires (19%), or plates (7%). Flattening of foot arch after treatment was observed in 42.9% of patients, with significant increases in Costa-Bertani (12 ± 7 degrees), Hibbs (7 ± 6 degrees), and Meary (3 ± 1 degrees) angles. Other complications included complex regional pain syndrome (28.6%) and painful hardware (23.8%). Secondary joint arthrodesis was needed in 16.6% of patients. Chronic pain was present in 71.4% of patients with a mean visual analog scale (VAS) pain score at final follow-up of 4 of 10 points. Results in AOFAS midfoot score and FFI were 87.4 ± 8.3 and 15 ± 6.4, respectively.

CONCLUSION

The subtle Lisfranc injury shows dissociation between the initial relatively mild radiographic changes and important future complications. Chronic pain and foot arch flattening were not uncommon. Overall foot function in the short- or midterm was found to be modestly diminished in this somewhat heterogenous cohort.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

The Lisfranc Injury: A Literature Review of Anatomy, Etiology, Evaluation, and Management

Despite being first described in the 1800s, the Lisfranc injury remains one of the most controversial topics in foot and ankle surgery. From the basic anatomy of the ligament complex to the optimal diagnostic and management methods, new research both sharpens and yet confounds our understanding of this unique injury. This article reviews the literature from established and classic papers to recent studies evaluating newer techniques. We discuss the unique bony and ligamentous anatomy, which confer strength to the Lisfranc complex, the typical mechanisms of injury, the most common classification systems, the clinical presentation, current imaging modalities, and conservative and surgical treatment options. We review studies comparing open reduction and internal fixation with primary arthrodesis of acute injuries, in addition to studies evaluating the various methods for obtaining fixation, including intra-articular screws, dorsal plates, and flexible fixation. It is clear from this review that despite the vast number of studies in the literature, much is still to be learned about the diagnosis and management of this challenging injury.Levels of Evidence: Level V: Expert opinion.

Anatomy and biomechanics of the Lisfranc ligamentous complex: A systematic literature review

Lisfranc injuries are challenging to treat and can have a detrimental effect on active individuals. Over the past decade researchers have investigated methods for the reconstruction of the Lisfranc ligamentous complex (LLC) to preserve its functional stability and mobility. To aid in this innovation, this study presents the current understanding of the anatomical and biomechanical characteristics of the LLC through a systematic review. Three medical databases (PubMed, Scopus, and Embase) were searched from inception through July 2019. Original studies investigating the anatomy and/or biomechanical properties of the LLC were considered for inclusion. Data recorded from each study included: number of cadavers, number of feet, gender, laterality, age, type of specimen, measurement methods, reported ligamentous bundles, ligament origins and insertions, geometric characteristics, and biomechanical properties of the LLC. The Quality Appraisal for Cadaveric Studies (QUACS) scale was used to assess the methodologic quality of included articles. Eight cadaveric studies investigating the LLC were included out of 1204 screened articles. Most articles described the LLC as three distinct structures: the dorsal- (DLL), interosseous- (ILL), and plantar- (PLL) Lisfranc Ligaments. The ILL had the largest thickness and insertional area of osseous attachment. Biomechanically, the ILL also had the highest stiffness and resistance to load prior to failure when loaded parallel to its fiber orientation. Current knowledge of the anatomical and biomechanical properties of the LLC are presented and highlight its significant role of stabilizing the tarsometatarsal articulation. Appreciating the biomechanical characteristics of the ILL may improve clinical insight in managing LLC injuries.

Absence of Posttraumatic Bone Marrow Edema in the Setting of Preeclampsia

Magnetic resonance imaging is a powerful tool in the diagnosis of missed or occult fractures on radiographic and computed tomographic (CT) imaging, through the detection of bone marrow edema. Although radiologists often rely on bone marrow edema as a guide for diagnosing subtle underlying fractures, it is important to recognize its limitations as a diagnostic metric. We present a rare case demonstrating the absence of bone marrow edema after acute trauma and confirmed Lisfranc fracture in a patient with preeclampsia and propose an interesting physiologic mechanism to explain this manifestation.

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

BACKGROUND

Subtle Lisfranc joint injuries remain challenging to diagnose. Although of questionable accuracy, the current gold standard to assess these injuries is through bilateral weight-bearing radiography. However, weight-bearing cone beam-computed tomography (CBCT), providing clearer visualization of bony landmarks, can also be utilized for evaluation. This study aims to establish the hypothesis that a specific weight-bearing CBCT finding (asymmetric lambda sign) can serve as an independent indicator of a subtle Lisfranc injury.

METHODS

Weight-bearing CBCT images of 24 match-paired cadaveric legs were acquired, initially intact, and then following sequential dissection of each aspect (dorsal, interosseous, and plantar ligaments, respectively) of the Lisfranc ligamentous complex (LLC). All scans were taken in non- (NWB, 0 kg), partial- (PWB, 40 kg), and full-weight-bearing (FWB, 80 kg) manners. The lambda sign was then inspected axially for asymmetry (positive sign) by identifying three symmetrical joint spaces created between the medial cuneiform and the second metatarsal base (C1-M2), the medial and middle cuneiform (C1-C2), and the second metatarsal base and middle cuneiform (M2-C2).

RESULTS

A positive sign was observed in 25.6% (221/864) of all studies. Most notably, the fully dissected specimens demonstrated an asymmetric lambda sign in 33.3%, 72.2%, and 83.3% in NWB, PWB, and FWB conditions, respectively. The inter- and intra-observer reliability kappa value was calculated to be 0.843 and 0.912.

CONCLUSION

An asymmetric lambda sign is a simple and useful indicator for a complete LLC injury in PWB and FWB conditions using a cadaver model.

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.

Dynamic Stress MRI of Midfoot Injuries: Measurable Morphology and Laxity of the Sprained Lisfranc Ligament During Mechanical Loading: A Case Report

CASE

Our 26-year-old patient is a professional ballet dancer who suffered a classic Lisfranc joint injury while performing a dancing maneuver with his foot in full plantar flexion. Initial workup with radiographs revealed borderline Lisfranc interval widening without definitive joint instability. Further evaluation with an innovative dynamic stress magnetic resonance imaging (MRI) revealed mild interosseous Lisfranc ligament laxity and sprain, which allowed the orthopaedic surgeon to pursue conservative management, rather than surgery. After physical therapy, our patient reports a successful return to dancing.

CONCLUSIONS

Dynamic stress MRI may become a useful technique in evaluating equivocal cases of midfoot injury through the use of new imaging-based criteria.

Incidence and Characteristics of Midfoot Injuries

BACKGROUND:

The epidemiology of midfoot injuries is poorly known. It has been estimated that the incidence of Lisfranc injuries (intra-articular injury in the tarsometatarsal joint) is 1/55 000 person-years and the incidence of Chopart injuries (intra-articular injury in the talonavicular and calcaneocuboidal joint) 4/100 000 person-years. The purpose of our study was to assess the computed tomography (CT) imaging-based incidence (per 100 000 person-years) and trauma mechanisms of midfoot injuries.

METHODS:

All CT studies performed due to acute injury of the foot and ankle region between January 1, 2012, and December 31, 2016, at Tampere University Hospital were reviewed. Patients presenting with an injury in the midfoot region in the CT scan were included in this study, and their records were retrospectively evaluated to assess patient characteristics.

RESULTS:

During the 5-year study period, 953 foot and ankle CT scans were obtained because of an acute injury of the foot and ankle. Altogether, 464 foot injuries were found. Of these, 307 affected the midfoot area: 233 (75.9%) the Lisfranc joint area, 56 (18.2%) the Chopart joint area, and 18 (5.9%) were combined injuries or miscellaneous injuries in the midfoot. The incidence of all midfoot injuries was 12.1/100 000 person-years. The incidence of Lisfranc injuries was 9.2/100 000 person-years. The incidence of Chopart injuries was 2.2/100 000 person-years.

CONCLUSIONS:

The incidence of Lisfranc injuries was higher and the incidence of Chopart injuries lower than previously estimated. More than two-thirds of the midfoot injuries in this study were nondisplaced (<2 mm displacement in fracture or joint) and were caused by low-energy trauma.

LEVEL OF EVIDENCE:

Level III, epidemiologic study.

Lisfranc Joint Ligament Complex Reconstruction: A Promising Solution for Missed, Delayed, or Chronic Lisfranc Injury Without Arthritis

The current classifications of "Lisfranc injury" can be purely ligamentous (low-grade midfoot sprains) or involve the osseous and articular structures (high-grade Lisfranc fracture displacements). The first type is often difficult to detect. If these patients are not properly treated, long-term disability can result. The rate of missed or delayed diagnoses has ranged from 13% to 24%, primarily owing to the subtlety of the radiographic findings. This is relatively more common in cases of subtle ligamentous injury (19%). The aim of the present report was to provide a new technique for missed or delayed Lisfranc injury without degenerative local signs. The Lisfranc ligament complex reconstruction is performed with a gracilis tendon graft and is protected by temporary screw fixation. We performed this technique in 3 patients. All 3 patients obtained good results, have been able to resume their previous activities, and have stated they would undergo this type of procedure again. The minimum follow-up length was 2 years.

Subtle Lisfranc Injuries: A Topical Review and Modification of the Classification System

Lisfranc injuries are relatively uncommon. No specific incidence of subtle injuries has been reported; however, almost one-third are missed on initial review. These missed injuries are a common cause of litigation. Although seen in high-energy injuries with direct application of forces, they are also associated with lower-energy indirect mechanisms, often on the athletic field. This article provides a topical review of subtle Lisfranc disruptions, focusing on contemporary perspectives, and describes a modification to the most prevalent classification system. [Orthopedics. 2018; 41(2):e168-e175.].

MR Imaging Evaluation of the Lisfranc Ligament in Cadaveric Feet and Patients With Acute to Chronic Lisfranc Injury

BACKGROUND

Magnetic resonance (MR) imaging is known to be useful to demonstrate Lisfranc ligament injury. There are few studies that report differences in MR imaging findings of acute or chronic Lisfranc ligament injuries. We applied oblique MR imaging planes parallel to the Lisfranc ligament for better visualization of the entire course of the ligament and assessed the detailed MR imaging appearances of the Lisfranc ligament in cadavers and patients with presumed Lisfranc injuries.

METHODS

Twelve preserved cadaveric feet were examined using a small-diameter surface coil. Long axis, oblique sagittal, and oblique short axis cross sections parallel to the Lisfranc ligament, dorsal ligament, and plantar ligament were obtained. Twenty-six MR examinations from 23 patients with suspected Lisfranc joint injuries were evaluated.

RESULTS

In the cadaveric study, the Lisfranc ligament was satisfactorily visible along its entire course in a single slice on long axis and oblique sagittal MR images. The dorsal ligament and the plantar ligament were visible separately from the Lisfranc ligament in oblique sagittal and oblique short axis planes. In the patient study, 11 MR examinations led to diagnoses of complete tears of the Lisfranc ligament that were acute injuries (3-21 days after trauma) mostly associated with disruption of the dorsal and plantar ligaments. Nine studies led to diagnoses of incomplete tears of the Lisfranc ligament that were chronic injuries (2-14 months after trauma). Recovery of the continuity of the disrupted ligament was observed in 3 patients.

CONCLUSION

MR imaging demonstrated the integrity of the ligaments and was useful for diagnosing an acute Lisfranc injury. Fibrous healing of the torn ligament was observed in a chronic injury.

Midfoot and Forefoot Injuries

Sports injuries of the midfoot and forefoot encompass a spectrum of osseous and soft tissue trauma. Magnetic resonance imaging serves as a primary or important supplementary diagnostic modality in evaluation of various injuries, most important of which include Lisfranc complex injury, stress fractures, and injury to the first metatarsophalangeal joint, aka "turf toe." Current technical advances in magnetic resonance and improved knowledge of regional anatomy enable thorough evaluation of the complex anatomic structures of the foot and facilitate accurate diagnosis in the setting of trauma.

Ligaments of the Lisfranc joint in MRI: 3D-SPACE (sampling perfection with application optimized contrasts using different flip-angle evolution) sequence compared to three orthogonal proton-density fat-saturated (PD fs) sequences

PURPOSE

To compare the detection rate and visibility of the ligaments in the Lisfranc joint with a single 3D (-SPACE) MR sequence and three orthogonal PD fat-saturated sequences.

MATERIALS AND METHODS

Thirty-one asymptomatic feet and 15 patients with posttraumatic pain in the Lisfranc joint were evaluated with a 3D-SPACE-sequence (0.5 mm section thickness, acquisition time 10:22 min, secondary reformations) and three orthogonal PD fs sequences (2 mm section thickness, 9:20 min). The Lisfranc-ligament, the dorsal and plantar tarsometatarsal ligaments (TMT), the dorsal, interosseous, and plantar intermetatarsal ligaments (IMT) (24 ligaments for each foot) were assessed.

RESULTS

In asymptomatic feet, 692 ligaments were detected with the SPACE sequence, thereof 90.6 % exhibited normal signal, and most (96.9 %) were completely visible on one single image. A total of 659 ligaments were detected with the PD fs sequence, thereof 86.6 % yielded normal signal, and 28.5 % were completely visible on one single image. In patients, 327 ligaments were detected with SPACE, thereof 50.6 % appeared completely visible with high signal. On PD fs, 308 ligaments were detected, 42.2 % of the ligaments had high signals.

CONCLUSIONS

The ligaments of the Lisfranc joint are better detected with a single 3D-SPACE sequence and secondary reformations than with three orthogonal PD fs sequences.

Age, sex, causal and injury patterns in tarsometatarsal dislocations: a literature review of over 2000 cases

BACKGROUND

The causes and mechanisms of tarsometatarsal (TMT) dislocations are poorly characterized. Unfortunately, the rarity of these injuries makes it difficult and costly to gather the epidemiological data needed to better understand the populations at risk and the circumstances under which injury is most likely to occur.

METHODOLOGY

To address this issue, literature reports of TMT dislocations were identified and analyzed to generate statistical descriptions of the common causes of injury, the age and sex of those injured, and the pattern of injury. Over 2000 injuries were identified from 187 articles.

RESULTS

The analysis reveals that over 40% of injuries were related to traffic accidents. Based on the Hardcastle classification system, more than 60% of TMT dislocation were partial (type B) injuries. Over 55% of the injured were between 15 and 35 years of age, and males were injured more than twice as frequently. Conversely, the victims of falls tended to be older and represented a larger proportion of females. The age and sex of those injured by TMT dislocations vary by cause.

CONCLUSION

An improved understanding of the epidemiologic patterns will benefit research into the mitigation and prevention of these injuries.

Subtle Lisfranc joint ligament lesions: surgical neoligamentplasty technique

The results achieved with this technique after a mean follow-up of 8 years (85% excellent and good results) allow neoligamentplasty to be considered as a viable alternative to the classic procedures in the treatment of subtle intercuneiform and tarsometatarsal joint lesions.

The midfoot sprain: a review of Lisfranc ligament injuries

The subtle clinical and radiographic findings of an unstable Lisfranc ligament injury can be easily misdiagnosed as a stable midfoot sprain. Appropriate treatment ranges from conservative management to surgery, depending on the extent of ligament disruption and subsequent joint instability. Initial evaluation with non-weight bearing radiographs is often normal in unstable injuries. The results of missed or inappropriately treated Lisfranc injuries are poor. Chronic joint instability can lead to persistent pain, degenerative joint disease, and decreased functional capacity. Inability to return to previous levels of activity may result from painful midfoot arthritis. It is important to have a high index of suspicion for unstable Lisfranc injuries in patients who present with midfoot pain after low-energy injuries. Stress radiographs and magnetic resonance imaging can help differentiate between stable and unstable ligament sprains. Referral to an orthopedic surgeon is appropriate for injuries that result in joint diastasis. Long-term outcomes are optimized by early anatomic reduction.

Vector correlation technique for pixel-wise detection of collagen fiber realignment during injurious tensile loading

Excessive soft tissue loading can produce adverse structural and physiological changes in the absence of any visible tissue rupture. However, image-based analysis techniques to assess microstructural changes during loading without any visible rupture remain undeveloped. Quantitative polarized light imaging (QPLI) can generate spatial maps of collagen fiber alignment during loading with high temporal resolution and can provide a useful technique to measure microstructural responses. While collagen fibers normally realign in the direction that tissue is loaded, rapid, atypical fiber realignment during loading may be associated with the response of a local collagenous network to fiber failure. A vector correlation technique was developed to detect this atypical fiber realignment using QPLI and mechanical data collected from human facet capsular ligaments (n=16) loaded until visible rupture. Initial detection of anomalous realignment coincided with a measurable decrease in the tissue stiffness in every specimen and occurred at significantly lower strains than those at visible rupture (p<0.004), suggesting this technique may be sensitive to a loss of microstructural integrity. The spatial location of anomalous realignment was significantly associated with regions where visible rupture developed (p<0.001). This analysis technique provides a foundation to identify regional differences in soft tissue injury tolerances and relevant mechanical thresholds.