Abduction stress and AP weightbearing radiography of purely ligamentous injury in the tarsometatarsal joint

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.

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.

The First Tarsometatarsal Joint in Lisfranc Injuries

BACKGROUND

Lisfranc injuries are among the most debilitating injuries to the foot. Characterization of first tarsometatarsal (TMT) joint involvement in Lisfranc injuries is limited. Multiple studies have indicated that this joint is damaged in a variety of Lisfranc injury patterns, but there is sparse information regarding how often and in what form.

METHODS

A retrospective review was performed of operative Lisfranc fractures from 2010 to 2020 with patients identified by Combined Procedural Terminology codes. Hardcastle and Myerson Lisfranc injury classifications and computed tomography and radiograph characterizations of the first TMT joint were evaluated by 3 foot and ankle fellowship-trained orthopaedic surgeons. Radiographic characteristics were collected. Light's kappa coefficient evaluated interrater reliability for injury classification. Injury mechanism and Lisfranc classification effects on the first TMT joint were further assessed using inferential statistics.

RESULTS

Of 71 patients with a Lisfranc injury of which 37 (52%) were high energy, 61 (86%) showed radiographic evidence of first TMT joint injury. A fragment was present in the TMT articular surface in 33 (47%) with median size = 8.7 mm and medial capsular avulsion in n = 25 (35%). Forty-eight patients (68%) had medial/lateral TMT joint incongruence ≥2 mm (median overhang = 4 mm), 21 (30%) had dorsal/plantar incongruence (median overhang = 6 mm). Angulation of TMT articular surfaces ≥5 degrees on the transverse/anteroposterior plane occurred in n = 32 (45%) and in n = 12 (17%) on the sagittal/lateral plane, which significantly differed between classifications (P = .020).

CONCLUSION

The overwhelming majority of Lisfranc midfoot injuries seen at our tertiary referral center had imaging evidence of damage to the first TMT joint (86%), and the incidence may be higher. The most common patterns of first TMT joint involvement we found were joint incongruity, articular surface fractures, angulation of the articular surfaces, and medial capsular ligament avulsion fractures. A better understanding of injuries to the first TMT joint can help orthopaedic surgeons with diagnosis.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

In-Season Management of Acute and Subacute Sports Foot Injuries

In athletes, foot injuries present with a variety of mechanisms, severity, and implications for return to play. Although potentially given less attention than knee and shoulder injuries by the team physician, foot injuries are common and thus require knowledgeable consideration. In this article, we review the anatomy, presentation, workup, and management of several of the most common athletic foot injuries, including turf toe, Lisfranc injuries, Jones fractures, and navicular stress fractures. The goal is to provide the team physician with the information necessary to evaluate and manage these injuries on the sideline and in the training room.

Updates on Lisfranc Complex Injuries

Lisfranc injuries are a disruption of one or more of the tarsometatarsal joints and have an estimated incidence of 1/55 000 people. However, the total number of Lisfranc injuries could be underreported, because almost 20% of these injuries are initially missed. Because of the relative infrequency of these injuries, the current literature is inconsistent in regard to proper treatment. This article provides a review of Lisfranc complex injuries including relevant anatomy, diagnosis, treatment, classifications, operative approaches, and outcomes and complications. Based on existing evidence, it also proposes an algorithm the authors prefer for the evaluation and treatment of Lisfranc complex injuries.

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."

Clinical study on the surgical treatment of atypical Lisfranc joint complex injury

BACKGROUND

Lisfranc injuries have not received much attention by orthopedic doctors in the past, and there is little related research on the diagnosis and treatment of these injuries. In recent years with the rise in foot and ankle surgery, doctors are now paying more attention to this type of injury. However, there is still a high rate of missed diagnosis due to insufficient attention causing treatment delays or inadequate treatments, which eventually result in greater sequelae; including long-term pain, arthritis, foot deformity etc. In particular, for cases with a mild Lisfranc joint complex injury, the incidence of sequelae is higher.

AIM

To select an active surgical treatment for an atypical Lisfranc joint complex injury and to evaluate the clinical efficacy of the surgical treatment.

METHODS

The clinical data of 18 patients, including 10 males and 8 females aged 20-64 years with Lisfranc injuries treated in our department from January 2017 to September 2019 were retrospectively analyzed. All patients were treated with an open reduction and internal fixation method using locking titanium mini-plates and hollow screws or Kirschner wires. X-ray images were taken and follow-up was performed monthly after the operation; the internal fixation was then removed 4-5 mo after the operation; and the American Orthopedic Foot and Ankle Society (AOFAS) score was used for evaluation on the last follow-up.

RESULTS

All patients were followed up for 6-12 mo. A good/excellent AOFAS score was observed in 88.9% of patients.

CONCLUSION

For atypical Lisfranc joint complex injuries, active open reduction and internal fixation can be performed to enable patients to obtain a good prognosis and satisfactory functional recovery.

Dynamic MR imaging analysis of instability in the injured Lisfranc joint with an MRI-compatible foot stressor device

PURPOSE

To evaluate the applicability of an MRI-compatible foot stressor device in patients with image-proven or clinically suspected Lisfranc joint injuries.

METHOD

This prospective study evaluated Lisfranc joint injury by utilizing a joint-specific, stress device that was engineered to replicate weightbearing and physical examination maneuvers. Sixteen patients with either clinically suspected or image-proven Lisfranc joint injuries were recruited from September 2018 to November 2019 (9 men, 7 women; mean age, 39.3 years; age range, 14-68 years). Resting and stressed MR sequences of the injured and non-injured feet were obtained. Measured values for Lisfranc interval widths, dorsal tarsometatarsal subluxations, and lambda-angles were subtracted between the stressed and resting images to calculate net stress-induced changes. A graded injury schema was used to measure significance.

RESULTS

The foot stressor device reliably generated stress-induced changes in the Lisfranc joint during dynamic MRI examination. All morphologically abnormal ligaments on resting images demonstrated stress-induced changes, whereas all morphologically normal ligaments lacked evidence of instability. More severely injured Lisfranc ligaments allowed greater Lisfranc joint widening (IOL, p < 0.001; PCL, p < 0.001; DCL, p < 0.001). More highly graded DCL injuries allowed greater dorsal TMT subluxation when present (p < 0.001). Angular gain in the midfoot (lambda-angle) correlated with the graded IOL score (p < 0.001). Acute-to-subacute injuries demonstrated greater inducible changes than chronic injuries (p = 0.047). Seven patients underwent surgery and nine patients received physical therapy.

CONCLUSIONS

Stress-induced changes in the midfoot provided information on the degree of ligament pathology and associated joint instability in Lisfranc joint injuries.

Low-Energy Lisfranc Injuries: When to Fix and When to Fuse

Lisfranc injuries can be devastating to the athlete and nonathlete. In the athletic population, minor loss of midfoot stability compromises the high level of function demanded of the lower extremity. The most critical aspect of treatment is identifying the injury and severity of the ligamentous/articular damage. Not all athletes are able to return to their previous level of function. With appropriate treatment, a Lisfranc injury does not mandate the cessation of an athletic career. We focus on the diagnosis and an algorithmic approach to treatment in the athlete discussion the controversy of open reduction and internal fixation versus arthrodesis.

Lisfranc injuries: Incidence, mechanisms of injury and predictors of instability

BACKGROUND

In Lisfranc injuries the stability of the tarsometatarsal joints guides the treatment of the injury. Determining the stability, especially in the subtle Lisfranc injuries, can be challenging. The purpose of this study was to identify incidence, mechanisms of injury and predictors for instability in Lisfranc injuries.

METHODS

Eighty-four Lisfranc injuries presenting at Oslo University Hospital between September 2014 and August 2015 were included. The diagnosis was based on radiologically verified injuries to the tarsometatarsal joints. Associations between radiographic findings and stability were examined.

RESULTS

The incidence of Lisfranc injuries was 14/100,000 person-years, and only 31% were high-energy injuries. The incidence of unstable injuries was 6/100,000 person-years, and these were more common in women than men (P = 0.016). Intraarticular fractures in the two lateral tarsometatarsal joints increased the risk of instability (P = 0.007). The height of the second tarsometatarsal joint was less in the unstable injuries than in the stable injuries (P = 0.036).

CONCLUSION

The incidence of Lisfranc injuries in the present study is higher than previously published. The most common mechanism of injury is low-energy trauma. Intraarticular fractures in the two lateral tarsometatarsal joints, female gender and shorter second tarsometatarsal joint height increase the risk of an unstable injury.

LEVEL OF EVIDENCE

Level III, cross-sectional study.

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.

The Influence of Percentage Weight-Bearing on Foot Radiographs

Introduction: Clinical decisions are often made on weight-bearing radiographs. However, it is unknown whether various weight-bearing conditions alter specific radiographic measurements. The purpose of this study was to determine whether percentage weight-bearing influences radiographic measurements of the normal foot. Methods: A prospective study with 20 healthy individuals had radiographs of the foot under 5 weight-bearing conditions (non-weight-bearing, 10% body weight, 25% body weight, 50% body weight, and 100% body weight). Measurements were made of hallux valgus angle (HVA), 1-2 intermetatarsal angle (IMA), talonavicular coverage angle (TNCA), talocalcaneal angle (TCA), forefoot width, LisFranc distance, cuboid height to ground (CHG), and talo-first metatarsal angle (TMA) of each weight-bearing condition. Statistical differences of each measurement for each weight-bearing condition were determined. Results: The TNCA and TCA increased significantly, whereas the CHG decreased significantly with increased percentage body weight. There were no differences in HVA, IMA, forefoot width, LisFranc distance, and TMA with increased percentage body weight. Conclusions: This study shows an increase in TNCA and TCA, and decrease in CHG, demonstrating a flattening of the medial arch, increasing hindfoot valgus, and midfoot external rotation and abduction with increasing percentage body weight applied to a foot. Percentage weight-bearing does not change radiographs in the foot between 25% and 100% weight-bearing. The clinical relevance of this finding is that graduated postinjury or postoperative weight-bearing regimens may only be relevant if the patient is either less than or greater than 25% of body weight on their extremity. Levels of Evidence: Case Series, Level IV: Prospective.

Undisplaced subtle ligamentous Lisfranc injuries, conservative or surgical treatment with percutaneous position screws?

PURPOSE

Undisplaced subtle ligamentous Lisfranc injuries are easy to miss or underestimate, and many cases are treated without surgical fixation. It has not yet widely known whether conservative treatment for undisplaced subtle ligamentous Lisfranc injuries may lead to a poor outcome. The purpose of this study is to compare the outcomes of conservative versus surgical management (percutaneous position screw) of undisplaced subtle ligamentous Lisfranc injury.

METHODS

We analysed 61 cases in this retrospective study, including 38 males and 23 females. Forty-one patients were managed conservatively, while 20 patients received surgical treatment involving minimal invasive percutaneous position screw. American orthopaedic foot &ankle society (AOFAS), foot function index (FFI, including FFI disability, FFI pain score and activity limitation scale) scores, Maryland foot score and short form-36 (SF-36) were recorded and compared after a follow-up of 10-16 months (average 12.3).

RESULTS

Patients in the surgical management group had higher scores in all evaluation methods (p < 0.05). The complications in the conservative management group had higher incidence, mainly including secondary diastasis (34.1% vs. 5.0%), joint stiffness after 3 months (82.9% vs. 0%), and secondary arthrodesis (12.2% vs. 0%). The highest rate of complication in surgical management group was temporary forefoot pain (55.0%).

CONCLUSION

The results of this study suggest that the outcomes of the surgical management with percutaneous position screw fixation are better than the conservative management to treat undisplaced subtle ligamentous Lisfranc injuries. This study can serve as a resource for orthopaedic surgeons in recognizing and managing such injuries.

Ligamentous Lisfranc Injury: A Biomechanical Comparison of Dorsal Plate Fixation and Transarticular Screws

OBJECTIVES

Optimal fixation technique after purely ligamentous Lisfranc injury remains controversial. This biomechanical study compares dorsal plate versus transarticular screw fixation by measuring dorsal and plantar joint diastasis. A unique protocol was developed, using reflective triad markers and positional cameras.

METHODS

Eleven cadaveric matched pairs were assigned to either transarticular screw or dorsal plate fixation. Two reflective triad markers were placed into the medial cuneiform (C1) and second metatarsal base (MT2). Three cameras recorded the 3-dimensional location of triads to quantify C1-MT2 diastasis in the following states: intact Lisfranc ligament (INTACT), cut ligament (CUT), fixed (SCREW or PLATE) joint, and fixed joint after 10,000 loaded cycles. On completion, the plantar Lisfranc ligament insertions were identified, and plantar diastasis was determined using additional reflective triads. Statistical post hoc pairwise comparisons assessed differences in diastasis.

RESULTS

C1-MT2 diastasis in the CUT state increased relative to INTACT (P < 0.001). SCREW fixation reduced C1-MT2 diastasis relative to CUT at dorsal (P < 0.007) and plantar (P = 0.015) locations after cycling. PLATE fixation significantly reduced dorsal diastasis relative to CUT (P < 0.001) but not for plantar diastasis (P > 0.99). PLATE plantar diastasis was numerically higher than INTACT but not significantly (P > 0.39). PLATE plantar diastasis tended to be greater than SCREW before cycling (P = 0.068) and after cycling (P = 0.080).

CONCLUSIONS

Transection of the Lisfranc ligament complex yielded C1-MT2 diastasis. Both SCREW and PLATE fixation successfully reduced dorsal diastasis. However, upon load, the PLATE resulted in greater plantar diastasis, nearly statistically different relative to the SCREW. Cyclic loading at 343 N did not worsen diastasis.

InternalBrace has biomechanical properties comparable to suture button but less rigid than screw in ligamentous lisfranc model

Purpose

The aim of this study was to investigate the biomechanical properties of the InternalBrace for lisfranc injuries.

Methods

A Sawbone model was developed comparing screw, suture button and InternalBrace.

Results

When loaded in axial tension at 0.5 mm/s, the screw was stiffest (2,240 N/mm), while the InternalBrace (200 N/mm) was stiffer than the suture button (133 N/mm). Cyclic loading with 10,000 cycles of 69 N, 138 N, and 207 N showed the InternalBrace maintained stiffness, but fatigued earlier than the suture button.

Conclusion

The mechanical properties of the InternalBrace support clinical use, but further studies are needed regarding early weight bearing.

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.].

Nonweightbearing Radiographs in Patients With a Subtle Lisfranc Injury

BACKGROUND

A midfoot sprain can be easily missed because of minimal findings on initial radiographs, which are almost universally nonweightbearing. We investigated preoperative nonweightbearing plain radiographic images in patients who were found to have unstable subtle Lisfranc injuries.

METHODS

We retrospectively reviewed 51 patients who were operated on between February 2004 and March 2015. Abnormal preoperative radiographic findings and intraoperative instability were compared. The relationship was calculated with Fisher's exact test.

RESULTS

Based on intraoperative findings, medial cuneiform (C1)-second metatarsal (M2) instability was observed in 50 cases (98%), which was the most common. Thirty-nine cases (76.4 %) had multiple joint (at least 2) instability. In the preoperative radiologic findings, C1-M2 diastasis was the most common abnormal finding, in 46 cases (90.1%). Specificity and positive predictive value were 1.0 in C1-M2 avulsion, diastasis, and C1-intermediate cuneiform (C2) diastasis. Abnormal findings of C1-C2, C1-M1, and C2-M2 showed a significant relationship with intraoperative instability ( P < .05).

CONCLUSION

C1-M2 avulsion and diastasis and C1-C2 diastasis were definite preoperative predictors of instability. In unstable subtle Lisfranc injuries, 90% had at least a minor radiographic abnormality at the C1-M2 joint on nonweightbearing radiographs. However, caution should be exercised to identify instability without radiographic abnormality in the C1-M2 joint.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Management of Tarsometatarsal Joint Injuries

Joint disruptions to the tarsometatarsal (TMT) joint complex, also known as the Lisfranc joint, represent a broad spectrum of pathology from subtle athletic sprains to severe crush injuries. Although injuries to the TMT joint complex are uncommon, when missed, they may lead to pain and dysfunction secondary to posttraumatic arthritis and arch collapse. An understanding of the appropriate anatomy, mechanism, physical examination, and imaging techniques is necessary to diagnose and treat injuries of the TMT joints. Nonsurgical management is indicated in select patients who maintain reduction of the TMT joints under physiologic stress. Successful surgical management of these injuries is predicated on anatomic reduction and stable fixation. Open reduction and internal fixation remains the standard treatment, although primary arthrodesis has emerged as a viable option for certain types of TMT joint injuries.

The Role of Percutaneous Reduction and Fixation of Lisfranc Injuries

To be able to perform percutaneous fixation of Lisfranc injuries, this article emphasizes that an anatomic reduction must be mandatory. When uncertainty remains as to whether closed reduction is anatomic, formal open reduction is recommended because accuracy of reduction is correlated with long-term outcome. Closed injuries with minimal displacement, bony avulsions, and skeletally immature individuals seem the most appropriate indications for percutaneous fixation. Not all injuries are ideal for this method of treatment, and this is an area that needs to be more clearly defined in the future.

Open Reduction and Internal Fixation Versus Primary Arthrodesis for Lisfranc Injuries

Management of injuries to the tarsometatarsal (Lisfranc) joint complex continues to generate heated debate. Arthrodesis of the Lisfranc joint complex has historically been reserved as a salvage procedure for failed treatment. Recently, primary arthrodesis has emerged as a viable treatment alternative to open reduction and internal fixation for these injuries. The objective of this article was to examine the current literature regarding open reduction and internal fixation versus primary arthrodesis of Lisfranc injuries.

Post-traumatic Arthritis of the Tarsometatarsal Joint Complex: A Case Report

Tarsometatarsal (TMT) arthritis is characterized by instability and pain in the foot. The commonest cause is post-traumatic arthritis. A Lisfranc injury involves the articulation between the medial cuneiform and the base of the second metatarsal, which is considered a keystone to midfoot integrity. Neglected or undertreated injury to the Lisfranc joint complex leads to secondary arthritis and significant disability. We present a case of a young male patient with a two-year-old neglected Lisfranc joint injury and secondary osteoarthritis of the first, second, and fourth TMT joints, which we treated surgically with arthrodesis using screws, with a good functional outcome on final follow-up.

Ligament reconstruction with single bone tunnel technique for chronic symptomatic subtle injury of the Lisfranc joint in athletes

INTRODUCTION

Only few procedures for Lisfranc ligaments reconstruction to treat subtle injury of the Lisfranc joint have been reported. We have developed a novel technique for Lisfranc ligaments reconstruction, which was applied to treat chronic symptomatic subtle injuries that had failed to respond to initial treatment or were misdiagnosed. This article describes the technique and its operative outcome in a small case series.

METHODS

Between April 2011 and October 2013, 5 (4 male and 1 female) athletes with a mean age of 19.4 (range 17-21) years were diagnosed with chronic subtle injury of the Lisfranc joint and underwent our novel reconstructive operation. In this technique, only a bone tunnel between the medial cuneiform and the second metatarsal bone is needed for near-anatomical reconstruction of the dorsal and interosseous ligaments. All patients were evaluated before and at 1 year after surgery using the American Orthopaedic Foot and Ankle Society (AOFAS) scale for the ankle-midfoot. In addition, the interval between surgery and return to athletic activity, defined as return to near pre-injury performance level, was investigated.

RESULTS

Mean duration of postoperative follow-up was 18.8 (range 12-26) months. Mean AOFAS score improved significantly from 74.6 ± 2.5 (range 71-77) preoperatively to 96.0 ± 5.5 (range 90-100) at 1 year after the operation (p < 0.01). All patients were able to return to their previous athletic activities and the interval between surgery and return to athletic activity was 16.8 ± 1.1 (range 15-18) weeks. There was no complication related to the operation.

CONCLUSION

The results of this study suggest that our technique of Lisfranc ligaments reconstruction using autologous graft is effective for athletes with chronic subtle injury.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Biomechanical analysis of endobutton versus screw fixation after Lisfranc ligament complex sectioning

BACKGROUND

Our goal was to compare diastasis after endobutton and screw fixation after Lisfranc ligament complex sectioning.

METHODS

Twenty-four (12 pairs) fresh-frozen cadaveric feet were assigned to endobutton or screw fixation and loaded to 343N. Displacement (first-second metatarsal bases) was measured in intact feet and after ligament sectioning (Lisfranc, medial-intermediate cuneiform ligaments), fixation, and 10,000 cycles.

RESULTS

The mean change in diastasis for endobutton and screw fixation under initial loading was 1.0mm (95% CI, 0.2-1.9mm) and 0.0mm (95% CI, -0.4 to 0.4mm), respectively (p=0.017). After cyclic loading, diastasis decreased (mean, -0.7mm, 95% CI, -1.2 to -0.1mm) in the endobutton group but was unchanged in the screw group (p=0.035).

CONCLUSIONS

Diastasis after endobutton fixation was significantly greater than after screw fixation under initial loading but did not increase further after cyclic loading.

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.

Technique tip: percutaneous fixation of partial incongruous Lisfranc injuries in athletes

Open reduction with screw fixation is considered the standard surgical approach for injuries of the Lisfranc complex in athletes. However, multiple incisions are required, which increase the risk for postoperative complications. We present a novel percutaneous reduction and solid screw fixation technique that may be a viable option to address partial incongruous injuries of the Lisfranc complex in athletes. At our institution, no intraoperative or postoperative complications have been encountered. Screw breakage did not occur. Reduction of the second metatarsal was considered anatomic across all patients. All patients have returned to their respective sport without limitation. The percutaneous approach appears to decrease complications while the targeting-reduction guide appears to precisely reduce the injury. Consequently, outcomes have been more consistent and predictable. The authors note that this percutaneous approach is specific to partial incongruous injuries of the Lisfranc complex. When presented with more extensive injuries, the authors advocate an open approach.

Three-dimensional, digital, and gross anatomy of the Lisfranc ligament

BACKGROUND

There are inconsistencies in the descriptive anatomy of the Lisfranc ligament. No information is available on orientation of fibers or presence of bundles, nor are there 3-dimensional anatomic data on the ligaments or their attachments. This study assessed the 3-dimensional anatomy of the Lisfranc ligament and its attachment sites.

METHODS

A total of 37 cadaver feet were dissected to expose the ligament attachments at the Lisfranc joint. The Lisfranc ligament and plantar ligament attachments were outlined separately and then removed with the attachment outlines preserved. A 3-dimensional digitizer was used to digitize bony and articular surfaces, as well as ligament attachment sites, at approximately 1 mm intervals; the positional accuracy was 0.23 mm. The surface areas of the entire bone, articular regions, and Lisfranc and plantar ligament attachment regions were determined and anatomic details were noted.

RESULTS

The Lisfranc ligament had a single bundle in 73% of the specimens and 2 bundles in 27%. Both variations had a single attachment to the second metatarsal (M2; mean attachment surface area, 135 mm(2)). The single-bundle variation attached to the medial cuneiform (C1; mean attachment surface area, 140 mm(2)). The plantar ligament, C1-M2-M3, attached to the anterior plantar surface of the lateral aspect of C1 (mean attachment surface, 64 mm(2)) and had attachment sites at the bases of M2 and M3. Its fibers ran anteriorly and inferiorly, with attachments to the proximal inferomedial aspect of M2 (mean attachment surface, 63 mm(2)) and fibers extending to a smaller attachment at the plantar aspect of M3 (mean attachment surface area, 26 mm(2)).

CONCLUSION

The Lisfranc ligament is variable in anatomy and can have a single- or double-bundle arrangement. Its area of attachment is larger than that of the plantar ligament.

CLINICAL RELEVANCE

Anatomic descriptions of location, dimensions, and variability in the position and surface area of the ligament attachment sites and of orientation of the bundles provide information for future attempts at repair or reconstruction of the Lisfranc ligament.

Ultrasound assessment of bilateral symmetry in dorsal Lisfranc ligament

Bilateral symmetry of the ligaments is a common assumption used as an intrasubject control for clinical diagnosis. The present study investigated the bilateral symmetry of the dorsal Lisfranc ligament (dLL) using ultrasound. Data were acquired from 50 asymptomatic subjects in a seated position at a loaded calf raise machine equipped with a force plate. The testing conditions included low, medium, and high stress at 0° and 15° abducted foot positions. Images of the dLL were captured and measured using a 10.0-MHz ultrasound transducer and custom written MATLAB software, respectively. The data were analyzed using paired t tests to compare the bilateral measurements of the dLL length under all test conditions. The bilateral pooled dLL length was 7.01 ± 1.38 mm and showed a moderate correlation with the foot length and width. No bilateral differences were found in the dLL length under any of the stress loads in the abducted position or under the medium and high stress load in the rectus position. However, the low stress load rectus position demonstrated a significant bilateral difference in the dLL length (p = .005). The smallest bilateral difference was observed at the 15° abducted position under medium stress (measurement error mean -0.062 mm). Our data suggest that the contralateral dLL length can be used as an intrasubject control for clinical purposes. However, we recommend that the dLL length measurements should be taken in weightbearing position with the foot in the abducted position under medium stress (bilateral stance), reducing potential strain-induced asymmetry.

Reliability of ultrasound imaging in the assessment of the dorsal Lisfranc ligament

Background

The Lisfranc ligament plays an integral role in providing stability to the midfoot. Variable clinical presentations and radiographic findings make injuries to the Lisfranc ligament notoriously difficult to diagnose. Currently, radiographic evaluation is the mainstay in imaging such injuries; however, ultrasound has been suggested as a viable alternative. The objective of this study was to evaluate the intra-rater and inter-rater reliability in the measurement of the length of the dorsal Lisfranc ligament using ultrasound imaging in healthy, asymptomatic subjects.

Methods

The dorsal Lisfranc ligaments of fifty asymptomatic subjects (n = 100 feet) were imaged using a Siemens SONOLINE Antares Ultrasound Imaging System^© under low, medium, and high stress loads at 0° and 15° abducted foot positions. The lengths of the ligaments were measured, and Interclass correlation coefficients were used to calculate within-session intra-rater reliability (n = 100 feet) as well as between-session intra-rater reliability (n = 40 feet) and between-session inter-rater reliability (n = 40 feet).

Results

The within-session intra-rater reliability results for dorsal Lisfranc ligament length had an average ICC of 0.889 (min 0.873 max 0.913). The average ICC for between-session intra-rater reliability was 0.747 (min 0.607 max 0.811). The average ICC for between-session inter-rater reliability was 0.685 (min 0.638 max 0.776).

Conclusions

The measurement of the dorsal Lisfranc ligament length using ultrasound imaging shows substantial to almost perfect reliability when evaluating asymptomatic subjects. This imaging modality methodology shows promise and lays the foundation for further work in technique development towards the diagnostic identification of pathology within the Lisfranc ligament complex.

Screw and wire fixation for Lisfranc fracture dislocations

PURPOSE

To assess mid-term outcome of screw and wire fixation for Lisfranc fracture dislocations to determine the risk factors of post-traumatic arthritis.

METHODS

15 men and 4 women aged 21 to 58 (mean, 41) years with Lisfranc fractures underwent open/ closed reduction and internal fixation (using screw and wire). Fractures were classified as homolateral (n=7), isolated (n=7), and divergent (n=5). Six patients had open fractures; 8 patients injured 5 tarsometatarsal joints; and 6 patients had pure ligamentous injury. Outcome (pain, function, and cosmesis) was assessed using the Maryland foot score and the American Orthopedic Foot and Ankle Society (AOFAS) score. Weight-bearing radiographs were evaluated for non-union, subluxation, malalignment, and post-traumatic arthritis.

RESULTS

Patients were followed up for 24 to 40 (mean, 30) months. Patients with anatomic reduction (n=14) achieved higher mean AOFAS foot score (79.3 vs. 67.5, p=0.0007) and Maryland foot score (80.4 vs. 69.4, p=0.0009) than did patients with non-anatomic reduction (n=5). Post-traumatic arthritis occurred significantly more often in patients with non-anatomic than anatomic reduction (3/5 vs. 1/14, p=0.037). Four patients developed post-traumatic arthritis, one of whom also developed lateral subluxation after implant removal. Two patients developed flat foot. Two patients had severe symptoms that limited function, one of whom underwent an arthrodesis. Two patients with compound fractures developed superficial infections. Three patients had broken screws.

CONCLUSION

Anatomic reduction is the main predictor of outcome in patients with Lisfranc fracture dislocations.

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

OBJECTIVE

The purpose of this study is to determine the diagnostic accuracy of radiographs in the diagnosis of Lisfranc injury. In addition, a foot phantom was investigated to determine the optimum degree of craniocaudal angulation on the anteroposterior radiograph to best show the joint. The angle of the joint in patients with midfoot injury was investigated to determine the optimum degree of craniocaudal angulation.

MATERIALS AND METHODS

Sixty patients examined by CT had their radiographs evaluated independently and by consensus opinion by two observers, and the diagnostic performance was calculated using CT as the reference standard. A foot phantom was radiographed with varying degrees of craniocaudal angulation, and the radiograph that best revealed the joint was determined. This was compared with the angle of the joint as measured on CT. The angle of the joint in all 60 patients was measured on CT.

RESULTS

The radiographs correctly identified 31 of the 45 cases (68.9%) of Lisfranc injury, with a positive predictive value of 84.4%, a negative predictive value of 53.3%, a sensitivity of 84.4%, and a specificity of 53.3%. Twenty degrees of craniocaudal angulation best showed the second tarsal-metatarsal joint of the phantom, and this correlated with a 20° angle measured by CT. The mean (± SD) angle of the joint in the patients was 28.9° ± 5.7°.

CONCLUSION

Conventional radiographs miss a significant number of cases of Lisfranc injury. Craniocaudal angulation can better show the joint, and an angle of 28.9° is likely to optimally visualize the joint in the majority of patients.

Treatment of Lisfranc fracture-dislocations with primary partial arthrodesis

BACKGROUND

The optimal method of treatment for Lisfranc fracture-dislocations remains controversial, and the role of primary partial arthrodesis for combined osseous-ligamentous Lisfranc injuries is unclear. This study reviewed the outcomes of Lisfranc injuries treated by primary partial arthrodesis.

METHODS

Patients who underwent primary partial arthrodesis for a primarily ligamentous or combined osseous and ligamentous Lisfranc fracture-dislocation were reviewed retrospectively and assessed at followup according to radiographic, clinical and standardized patient-based outcomes. Twenty-five patients (12 ligamentous, 13 combined), median age of 46 (range, 20 to 73) years, were followed for an average of 42 (range, 24 to 96) months.

RESULTS

The average American Orthopedic Foot and Ankle Society (AOFAS) score was 81 points (scale 0 to 100), with patients in general losing points for mild pain, limitations of recreational activities, and fashionable footwear requirements. There was no statistical difference between ligamentous and combined injuries with regard to the physical or mental component scores on the SF-36. At latest followup, patients reported an average return to 85% of their preinjury activity level (range, 50% to 100%). Twenty-one patients (84%) expressed satisfaction with their outcome and at latest followup, the mean visual analog pain scale (VAS) score was 1.8 out of 10 (range, 0 to 8). Three patients showed radiographic signs of post-traumatic arthritis of adjacent joints.

CONCLUSION

Treatment of both primarily ligamentous and combined osseous and ligamentous lisfranc injuries with primary partial arthrodesis produced good clinical and patient-based outcomes.

Subtle injuries to the lisfranc joint

The tarsometatarsal joint complex is an osseous and capsuloligamentous network that includes the 5 metatarsals, their articulations with the cuneiforms and cuboid, and the Lisfranc ligament, a strong interosseous attachment between the medial cuneiform and second metatarsal. A multitude of injury patterns exist involving the tarsometatarsal joint complex; a Lisfranc injury does not delineate a specific injury, but instead a spectrum of processes involving the tarsometatarsal joint complex.

Treatment of Lisfranc joint injury: current concepts

Injuries to the tarsometatarsal joint complex, also known as the Lisfranc joint, are relatively uncommon. However, the importance of an accurate diagnosis cannot be overstated. These injuries, especially when missed, may result in considerable long-term disability as the result of posttraumatic arthritis. A high level of suspicion, recognition of the clinical signs of injury, and appropriate radiographic studies are needed for correct diagnosis. When surgery is indicated, closed reduction with percutaneous screw fixation should be attempted. If reduction is questionable, open reduction should be performed. Screw fixation remains the traditional fixation technique.

Common Fractures and Injuries of the Ankle and Foot: Functional Anatomy, Imaging, Classification and Management

The ankle and foot are functionally important and complex joints. Bony fractures and ligamentous injuries are common. In this review paper we will discuss the functional anatomy, imaging, classification and the management of common ankle and foot injuries including ankle fractures, Achilles tendon ruptures, Lisfranc joint injuries, calcaneo fractures and fractures of the metatarsals and phalanges.

Stress radiographs in orthopaedic surgery

Stress radiographs are useful in determining the amount of ligamentous laxity present following trauma. The results may be helpful in determining diagnosis, surgical indications, and the type and timing of rehabilitation. Some techniques for obtaining stress radiographs involve specific patient positioning or manually applied force; others require use of a particular testing device. Stress radiographs may be obtained for a variety of anatomic areas and joints. The parameters that define abnormality on stress radiographs should be compared with those of clinical findings. The use of common and novel methods to obtain stress radiographs has led to improved identification and diagnosis of many orthopaedic pathologies. Some of these techniques have been developed with the aim of reducing patient discomfort or minimizing the clinician's exposure to radiation.

Lisfranc injuries in sport

Injuries to the Lisfranc ligament complex have traditionally been associated with high energy trauma such as motor vehicle collisions and industrial accidents. Recently, there has been a greater appreciation of mid-foot sprains that represent a spectrum of injury to the Lisfranc ligament complex. As a result, there has been an increased incidence of such injury resulting from low-energy trauma in activities ranging from recreational activity to elite athletic activity. This article discusses issues related to anatomy, clinical presentation, mechanism of injury, and diagnosis that are necessary to provide appropriate treatment for these injuries. There should be a high index of suspicion of this injury, and prompt diagnosis is important to allow athletes to return to sport with the best possible outcome.

Screw fixation compared with suture-button fixation of isolated Lisfranc ligament injuries

BACKGROUND

A cannulated screw is currently used to reduce and stabilize diastasis at the Lisfranc joint. The screw requires removal and may break in situ. A suture button does not have these disadvantages, but it is not known if it can provide stability similar to that provided by a cannulated screw or an intact Lisfranc ligament. The objective of the present study was to compare the stability provided by a suture button with that provided by a screw when used to stabilize the diastasis associated with Lisfranc ligament injury.

METHODS

Fourteen fresh-frozen, paired cadaveric feet were dissected to expose the dorsal region. A registration marker triad consisting of three screws was fixed to the first cuneiform and the second metatarsal. A digitizer was utilized to record the three-dimensional positions of the registration markers and their displacement in test conditions before and after cutting of the Lisfranc ligament and after stabilization of the joint with either a suture button or a cannulated screw. The first and second cuneiforms and their metatarsals were removed, and the ligament attachment sites were digitized. Displacement at the Lisfranc ligament and the three-dimensional positions of the bones were determined.

RESULTS

Loading with the Lisfranc ligament cut resulted in displacement that was significantly different from that after screw fixation (p = 0.0001), with a difference between means of 1.2 mm. Likewise, loading with the Lisfranc ligament cut resulted in a displacement that was significantly different from that after suture-button fixation (p = 0.0008), with a difference between means of 1.00 mm. No significant difference in displacement was found between specimens fixed with the suture button and those fixed with the screw.

CONCLUSIONS

Suture-button fixation can provide stability similar to that provided by screw fixation in cadaver specimens after isolated transection of the Lisfranc ligament.

Prediction of midfoot instability in the subtle Lisfranc injury. Comparison of magnetic resonance imaging with intraoperative findings

BACKGROUND

The objective of the present study was to assess the utility of magnetic resonance imaging for the diagnosis of an injury to the Lisfranc and adjacent ligaments and to determine whether conventional magnetic resonance imaging is a reliable diagnostic tool, with manual stress radiographic evaluation with the patient under anesthesia and surgical findings being used as a reference standard.

METHODS

Magnetic resonance images of twenty-one feet in twenty patients (ten women and ten men with a mean age of 33.6 years [range, twenty to fifty-six years]) were evaluated with regard to the integrity of the dorsal and plantar bundles of the Lisfranc ligament, the plantar tarsal-metatarsal ligaments, and the medial-middle cuneiform ligament. Furthermore, the presence of fluid along the first metatarsal base and the presence of fractures also were evaluated. Radiographic observations were compared with intraoperative findings with respect to the stability of the Lisfranc joint, and logistic regression was used to find the best predictors of Lisfranc joint instability.

RESULTS

Intraoperatively, seventeen unstable and four stable Lisfranc joints were identified. The strongest predictor of instability was disruption of the plantar ligament between the first cuneiform and the bases of the second and third metatarsals (the pC1-M2M3 ligament), with a sensitivity, specificity, and positive predictive value of 94%, 75%, and 94%, respectively. Nineteen (90%) of the twenty-one Lisfranc joint complexes were correctly classified on magnetic resonance imaging; in one case an intraoperatively stable Lisfranc joint complex was interpreted as unstable on magnetic resonance imaging, and in another case an intraoperatively unstable Lisfranc joint complex was interpreted as stable on magnetic resonance imaging. The majority (eighteen) of the twenty-one feet demonstrated disruption of the second plantar tarsal-metatarsal ligament, which had little clinical correlation with instability.

CONCLUSIONS

Magnetic resonance imaging is accurate for detecting traumatic injury of the Lisfranc ligament and for predicting Lisfranc joint complex instability when the plantar Lisfranc ligament bundle is used as a predictor. Rupture or grade-2 sprain of the plantar ligament between the first cuneiform and the bases of the second and third metatarsals is highly suggestive of an unstable midfoot, for which surgical stabilization has been recommended. The appearance of a normal ligament is suggestive of a stable midfoot, and documentation of its integrity may obviate the need for a manual stress radiographic evaluation under anesthesia for a patient with equivocal clinical and radiographic examinations.

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

OBJECTIVE

The objective of this study was to assess the utility of MRI in diagnosing injury to the first interosseous cuneometatarsal (Lisfranc) ligament and to additionally determine the associated patterns of traumatic soft tissue and osseous injury.

MATERIALS AND METHODS

Fifteen patients (16 feet) who were referred for MRI evaluation of the Lisfranc ligament, and had operative exploration or examination under anesthesia, were included for analysis. Standard non-contrast MRI foot imaging was performed in all cases. Evaluation of the following components was performed: the dorsal and plantar bundles of the Lisfranc ligament, the plantar tarsal metatarsal ligaments, soft tissue edema and fluid, and bone marrow edema and fractures. Surgical reports were regarded as the reference standard in all cases.

RESULTS

Seven of 10 cases of grade 3 Lisfranc ligament injuries at surgery were correctly graded at MRI. No cases of surgically proven complete Lisfranc ligament tears (grade 3) were interpreted as normal at MRI. All Lisfranc ligament sprains (grade 2 or 3) at surgery were detected at MRI. Two of six cases reported as grade 1 injuries at MRI were normal at surgery. No cases of surgically proven normal or sprained Lisfranc ligaments were interpreted as grade 3 tears on MRI. Four of six of our cases of normal or sprained Lisfranc ligaments demonstrated fractures; while the minority of complete Lisfranc ligament tears (3/10) contained fractures.

CONCLUSION

MRI is reasonably accurate at detecting traumatic injury to the Lisfranc ligament. However, in clinically suspected cases of traumatic Lisfranc ligament injury, true positive rate for sprain is low.

A minimally disruptive model and three-dimensional evaluation of Lisfranc joint diastasis

BACKGROUND

There is no model that can reproduce the diastasis at the Lisfranc joint after isolated transection of the Lisfranc ligament. Prior models required extensive sectioning of ligaments in the midfoot and represent injuries that cause extensive tarsometatarsal fracture-dislocations. They do not represent a subset of injuries that cause subtle or limited disruption at the Lisfranc joint. The purpose of this study was to create a model with the minimum amount of ligamentous disruption and loading necessary to consistently observe diastasis at the Lisfranc joint.

METHODS

Fourteen fresh-frozen paired cadaver feet were dissected to expose the dorsum. Three screws were inserted into each first cuneiform and second metatarsal to create a pair of registration triads. A digitizer was utilized to record the three-dimensional positions of the screws and their displacement under loaded and unloaded conditions before and after the Lisfranc ligament was cut (intact and cut conditions). The first and second cuneiforms and their metatarsals were removed, and the attachment sites of the dorsal and the Lisfranc ligament were digitized. The three-dimensional positions of the bones and ligament displacement were determined. The significance of differences between conditions was tested with analysis of variance, and linear regression analysis was used to test the correlation between dorsal and plantar displacements.

RESULTS

There was a significant difference, of 1.3 mm, in the mean displacement between the cut loaded and intact loaded conditions (p < 0.0001). A modest correlation (r(2) = 0.60) was found between dorsal displacement and displacement at the site of the Lisfranc ligament, possibly attributable to rotations between the first cuneiform and second metatarsal.

CONCLUSIONS

Isolated sectioning of the Lisfranc ligament is sufficient to consistently create diastasis at the Lisfranc joint. Dorsal displacements between the first cuneiform and second metatarsal are a modest predictor of plantar displacements.