Efficacy of Ultrasound Imaging in the Evaluation of the Lisfranc Joint Complex

Home , Lisfranc injury, Tarsometatarsal joints

THESIS

Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University

Meridith Kay DeLuca, B.S.

Graduate Program in Anatomy

The Ohio State University

2018

Master's Examination Committee:

Laura C. Boucher, PhD, ATC (Advisor)

Christopher Pierson, MD, PhD

Bryant Walrod, MD

Meridith Kay DeLuca

2018

Abstract

Lisfranc injuries account for 1 in 55,000 injuries yearly and are associated with poor outcomes and high complication rates. Located between the medial cuneiform and second metatarsal, the dorsal Lisfranc ligament is easily visualized with ultrasonography.

Ultrasound can provide quick, cost effective diagnosis of pathology, but is not standardized in practice. The purpose of this study was to compare measurement accuracy of the dorsal Lisfranc ligament between ultrasound and gross dissection with an additional anatomic study of the complex, including the dorsal, interosseous, and plantar

Lisfranc ligaments.

Ultrasound images of 22 embalmed cadaveric feet (11 male, 7 female, 80.3 years

± 14.03) were obtained using a Sonosite M-Turbo ultrasound machine. The dorsal

Lisfranc ligament was imaged and measured using a 6-13MHz linear array. Images were measured a second time using ImageJ software. Specimens were then dissected to evaluate the dorsal, interosseous, and plantar Lisfranc ligaments. Dorsal ligament measurements were compared between methodologies, and morphology of the joint complex was also recorded.

Differences in measurement of the dorsal Lisfranc ligament between ultrasound imaging (8.39 mm ± 1.26) and gross dissection (10.80 mm ± 1.85) were significant (p <

0.001). ImageJ measurements (8.24 mm ± 1.84) did not differ from ultrasound

i measurements, but were significantly different than dissection (p < 0.001). Dissection revealed the morphology of the dorsal and interosseous Lisfranc ligaments were consistent. The plantar ligament presented with variant morphology, demonstrating both a Y-shaped variant inserting separately on the 2nd and 3rd metatarsals, and a fan-shaped variant inserting across the metatarsals. A connection to the interosseous Lisfranc ligament was present in 64% of specimens. When compared to anthropometric measurements of the foot, no correlations were found with dorsal Lisfranc ligament length. Two specimens also possessed bony growths at the Lisfranc joint, raising questions regarding the prevalence of arthritis at the uninjured joint.

While the dorsal Lisfranc ligament is easily distinguishable on ultrasound, these data indicate that only 70-80% of the ligament is visible due to difficulty distinguishing the boney attachments. Wide variation of the plantar Lisfranc ligament was also noted, which may play into the relative vulnerability of the joint complex in some patients.

Further expansion of the current study could explore the differences between embalmed and fresh cadavers, and induced injury to cadaveric feet to compare ultrasound and dissection appearances of the injured Lisfranc joint complex.

Dedication

This document is dedicated to my friends and family.

iii

Acknowledgments

This thesis would not have been possible without the guidance, encouragement, and patience of my advisor, Dr. Laura Boucher. From the beginning, Dr. Boucher recognized the vision I had for my research, and provided countless hours of assistance and mentorship, for which I am beyond grateful. I would also like to thank my committee members. Dr. Chris Pierson has been an invaluable resource and support during my entire graduate education. Dr. Bryant Walrod’s insight and expertise in sports medicine has proved critical in carrying out the vision I have for this project, and ensuring that its findings are clinically relevant.

To Rachel Tatarski, I want to extend a special thank you for taking the time to be my research mentor and ultrasonography instructor. Additionally, I need to thank the friends and fellow students who provided hours of support and assistance at various stages of this project: Morgan Turnow, Kolin Korth, Meghan Flannery, Jay Vela, and

Spencer Gardner. I also want to thank the Division of Anatomy, which has been crucial in providing me with the opportunities to further my knowledge of the human body.

Finally, I thank the donors who participated in the Body Donation Program at The Ohio

State University, without whom my anatomical education would not have been possible.

Vita

2012...... Johannesburg-Lewiston High School, Johannesburg, Michigan

2016...... B.S. Biology, University of St. Francis

2016 to present ...... Graduate Student, Division of Anatomy, The Ohio State University

Fields of Study

Major Field: Anatomy

Table of Contents

Abstract ...... i

Dedication ...... iii

Acknowledgments...... iv

Vita ...... v

List of Tables ...... viii

List of Figures ...... ix

Chapter 1: Study Overview ...... 1

List of Abbreviations ...... 4

Chapter 2: Background ...... 5

2.1: Anatomy of the Lisfranc joint complex ...... 5

2.2: Lisfranc Injuries ...... 10

Mechanism of Injury ...... 10

Diagnosis ...... 13

Injury Treatment ...... 15

Patient Outcomes ...... 15

2.3: Ultrasound imaging of the Lisfranc joint complex ...... 18

2.4: Cadaveric Studies involving the Lisfranc Joint ...... 20

2.5: Current Study ...... 20

Chapter 3: Methods ...... 22

3.1: Ultrasound Methods ...... 23

3.2: Dissection Methods ...... 25

3.3: Analysis ...... 28

Chapter 4: Results – Ultrasonography of the Dorsal Lisfranc Ligament...... 29

Chapter 5: Results – Dissection of the Lisfranc Joint Complex ...... 34

Chapter 6: Discussion ...... 42

6.1: Ultrasound Imaging ...... 42

6.2: Cadaveric Dissection ...... 44

6.3: Clinical Relevance ...... 45

6.4: Limitations ...... 48

6.5: Future work ...... 52

6.6: Conclusions ...... 53

References ...... 55

Appendix A: Data Tables...... 59

Appendix B: Ultrasound Scan Protocol ...... 65

Appendix C: Dissection Protocol...... 66

vii

List of Tables

Table 1. Mean anthropometric measurements of the foot ...... 29

Table 2. Mean measurements of the DLL across modalities ...... 29

Table 3. One sample t-tests comparing DLL measurement ratios across modalities ...... 31

Table 4. One sample t-test of DLL thickness ratio ...... 31

Table 5. One sample t-tests for comparison of dorsal joint space across modalities ...... 33

Table 6. Mean gross measurements of the DLL ...... 35

Table 7. Mean gross measurements of the ILL ...... 36

Table 8. Mean gross measurements of the PLL fan variant ...... 38

Table 9. Mean gross measurements of the PLL variant with split morphology ...... 39

Table 10. Correlation of anthropometric measurements of the foot to gross DLL length 41

Table 11. Sex differences in gross DLL length ...... 41

Table 12. Cadaver information, including sex, age, and anthropometric measurements of the foot ...... 60

Table 13. Measurement of DLL using Sonosite M-Turbo, ImageJ, and gross dissection 61

Table 14. Measurement of the ILL in dissection ...... 62

Table 15. Measurement of the PLL fan variant in gross dissection ...... 63

Table 16. Measurement of the PLL split variant in dissection ...... 64

viii

List of Figures

Figure 1. Schematic of the Lisfranc ligaments at the tarsometatarsal/Lisfranc joint ...... 7

Figure 2. Cross sectional schematic of the Lisfranc ligaments ...... 9

Figure 3. Mechanism of low-energy Lisfranc injury ...... 11

Figure 4. Anthropometric measurements of the foot ...... 22

Figure 5. Initial probe placement on the dorsum of the foot ...... 23

Figure 6. Ultrasound imaging of the dorsal Lisfranc ligament ...... 24

Figure 7. Analysis of the dorsal Lisfranc ligament using ImageJ software ...... 25

Figure 8. En bloc dissection of the medial and central rays of the foot ...... 27

Figure 9. Comparison of mean DLL length between modalities ...... 30

Figure 10. Comparison of DLL thickness between modalities...... 31

Figure 11. One sample t-tests of dorsal joint space across modalities...... 32

Figure 12. Dissection of the DLL ...... 35

Figure 13. Dissection of the PLL fan variant ...... 37

Figure 14. Dissection of the ILL and PLL ...... 37

Figure 15. Dissection of the PLL split morphology ...... 38

Figure 16. Morphological variant of the PLL ...... 39

Figure 17. Comparison of ILL and PLL fan variant length to M2 insertion ...... 40

Figure 18. Sex differences in gross DLL length ...... 41

Figure 19. Ultrasound imaging of the DLL in vivo and in cadavers ...... 50 ix

Chapter 1: Study Overview

The Lisfranc, or tarsometatarsal joint, is the junction between the forefoot and the midfoot. The articulation consists of the five metatarsals, the three cuneiforms, and the cuboid (Hatem 2008). Across the articulation, ligaments connect the associated bones at the dorsal, interosseous, and plantar levels (Hatem 2008). Clinically, “Lisfranc injuries” are a general term encompassing injuries to bones and ligaments of the Lisfranc joint.

Lisfranc injuries account for only 1 in 55,000 injuries each year (Hardcastle et al. 1982), yet injury complications are common and carry high monetary impact (Calder et al.

2004). Reports of arthritis following open reduction and internal fixation (ORIF) of the joint range from 25 – 94% (Kuo et al. 2000, Welck et al. 2015), and 52% of patients who acquire a Lisfranc injury on the job pursue legal action and compensation claims (Calder et al. 2004).

Purely ligamentous Lisfranc injuries only account for one-third of Lisfranc injuries (Philbin et al. 2003), but are particularly difficult to diagnose. These injuries involve the Lisfranc joint complex: the dorsal, interosseous, and plantar Lisfranc ligaments as well as the medial cuneiform, second metatarsal, and third metatarsal. The current standardized diagnostic method involves weight bearing radiographs, which may cause patients significant pain and often result in a negative Lisfranc diagnosis. As a result, up to 20% of Lisfranc injuries are overlooked or misdiagnosed (Lewis et al. 2016). 1

Most emergency rooms and orthopedic clinics have ultrasound units readily available, and a shift toward the use of musculoskeletal ultrasound in diagnosing Lisfranc injuries has been recommended (Bica et al. 2015, Woodward et al. 2009). However, few clinicians are trained in the use of musculoskeletal ultrasound, making this diagnostic tool underutilized.

Diagnosis of Lisfranc injuries via ultrasound would have many benefits including reduction of radiation exposure, limited weight bearing for the patient, and immediate interpretation of results. This study aimed to determine the efficacy of ultrasound evaluation of the Lisfranc joint complex. Quantification of the dorsal Lisfranc ligament length and the dorsal joint space width through ultrasonography and gross dissection of cadaveric specimens was performed for comparison of accuracy between methodologies.

The first component of this study was quantitative and sought to evaluate accuracy of measurement for the dorsal Lisfranc ligament in ultrasonography. For this component, the following hypotheses were tested:

H0: There is no difference between the mean length of the dorsal Lisfranc

ligament between ultrasonography measurements and gross dissection

measurements.

HA: There is a significant difference between the mean length of the dorsal

Lisfranc ligament between ultrasonography measurements and gross dissection

measurements.

Ultrasound image measurements were repeated using ImageJ software to test the accuracy of measurement on the ultrasound unit. For this, the following hypotheses were tested:

H0: There is no difference between mean length of the dorsal Lisfranc ligament in

Sonosite M-Turbo and ImageJ measurements.

HA: There is a significant difference between mean length of the dorsal Lisfranc

ligament in Sonosite M-Turbo and ImageJ measurements.

The second component of this study was descriptive, and sought to examine the entire Lisfranc joint complex to provide a qualitative description of the dorsal, interosseous, and plantar Lisfranc ligaments.

This manuscript contains seven chapters. Chapter 2 will focus on the preexisting literature regarding the Lisfranc joint complex and its associated injuries. Chapter 3 will describe the methodology utilized in this study, which seeks to test the aforementioned hypotheses, and provide data for the descriptive component of this study. Collection of these data was achieved using ultrasound on cadaveric specimens and the subsequent dissection of these same specimens. Chapter 4 will provide the results from the statistical analysis of the study’s quantitative component. Chapter 5 will provide qualitative data for the study’s descriptive component. Chapter 6 will be a discussion of the study results in isolation, and in regard to the current body of literature. This chapter will also discuss potential limitations, expansions, and conclusions of the current study.

List of Abbreviations

1. C1 – Medial cuneiform

2. C2 – Intermediate cuneiform

3. C3 – Lateral cuneiform

4. Cu – Cuboid

5. M1 – First metatarsal

6. M2 – Second metatarsal

7. M3 – Third metatarsal

8. M4 – Fourth metatarsal

9. M5 – Fifth metatarsal

10. DLL – Dorsal Lisfranc ligament

11. ILL – Interosseous Lisfranc ligament

12. PLL – Plantar Lisfranc ligament

Chapter 2: Background

Originally described in 1815 by the French surgeon for whom it was named, the

Lisfranc joint is widely discussed in the clinical setting due to the complications, missed diagnoses, and poor outcomes that many patients face upon injury to this joint complex.

Jacques Lisfranc was a gynecologist and field surgeon in the French Napoleonic army.

While many orthopedic phrases have been coined using his name, including “Lisfranc joint”, “Lisfranc ligament(s)”, “Lisfranc injury”, and “Lisfranc fracture-dislocation”, none of these scenarios were actually described by Lisfranc himself. Instead, Lisfranc described a forefoot amputation at the tarsometatarsal joint line, a procedure which he performed on injured soldiers in less than one minute. These injuries were typically acquired when a cavalryman fell from a horse, but the foot remained caught in the stirrup of the saddle. Such injuries often resulted in vascular compromise and subsequent gangrene of the forefoot, which required amputation (DiDomenico et al. 2012). As a result of Lisfranc’s amputation procedure, the tarsometatarsal joint is often referred to as the Lisfranc joint (DiDomenico et al. 2012, Hatem 2008, DeOrio et al. 2009, Englanoff et al. 1995, Hardcastle et al. 1982).

2.1: Anatomy of the Lisfranc joint complex

The Lisfranc joint is described by some as the entire series of tarsometatarsal joints connecting the midfoot and forefoot (Lewis et al. 2016, Yu-Kai et al. 2015, 5

Panchbhavi et al. 2013, DiDomenico et al. 2012, Myerson et al. 2009, Hatem 2008,

Johnson et al. 2008, Shereif et al. 2007, Philbin et al. 2003, De Palma et al. 1997), while others describe it more specifically as the joint complex involving the second and third metatarsals (M2, M3) as well as the medial cuneiform (C1) (Kaicker et al. 2016, Welck et al. 2015, Rettedal et al. 2013, Hirano et al. 2013). For the purpose of this study, the

Lisfranc joint will be considered as the entire tarsometatarsal joint line of the foot, as this is the determination used by Bernstein (2003) in “Musculoskeletal Medicine,” the textbook used by The Ohio State University College of Medicine.

Despite inconsistencies that exist regarding the naming of the Lisfranc joint, an agreement predominates that the term “Lisfranc injuries” refers specifically to injuries involving the Lisfranc joint complex at the medial side of the tarsometatarsal joint

(Welck et al 2015, Woodward et al. 2009). This joint complex bridges two of the three synovial compartments of the foot – the medial and central rays. The medial ray consists of the articulation between the first metatarsal (M1) and C1, while the central ray consists of the articulations between M2 and the intermediate cuneiform (C2), and the articulation between M3 and the lateral cuneiform (C3). The lateral compartment, while not involved in Lisfranc injuries, consists of the articulations between the cuboid (Cu) and the fourth and fifth metatarsals (M4 and M5) (Figure 1) (DiDomenico et al. 2015, Myerson et al.

2009, Hatem 2008, De Palma et al 1997).

Figure 1. Schematic of the Lisfranc ligaments at the tarsometatarsal/Lisfranc joint. At the tarsometatarsal joint, the foot can be divided into medial, central, and lateral rays (a). The dorsal Lisfranc ligament (b) and interosseous Lisfranc ligament (c) both connect the medial cuneiform (C1) to the second metatarsal (M2). The plantar Lisfranc ligament (d) has a single origin on C1, and has insertions on both M2 and the third metatarsal (M3). Intermetatarsal ligaments are shown (grey). Also shown are the fourth and fifth metatarsals (M4 and M5), intermediate and lateral cuneiforms (C2 and C3), the cuboid (Cu), and the navicular (Nav)

Across the three rays of the foot – medial, central, and lateral – a pattern of ligaments is present. Three layers of ligaments span the joint spaces to provide support and stability; with a dorsal, interosseous, and plantar ligament for most articulations. The dorsal and plantar ligaments connect the respective surfaces of the two involved bones, while the interosseous ligaments connect the medial side of one bone to the lateral side of the adjacent bone. Transverse ligaments span the intertarsal joints between the three 7 cuneiforms and the cuboid, as well as the intermetatarsal joints in the dorsal and interosseous levels, with one exception. The intermetatarsal articulation between M1 and

M2 does not have a transverse ligament at any level, and thus, ligamentous support between M1 and M2 is achieved indirectly through the stabilization of the adjacent medial and central rays of the foot (DiDomenico et al. 2012, Hatem 2008, De Palma et al.

1997).

The second metatarsal, in addition to being the midline of the foot, is the longest of the metatarsals. Due to its exceptional length, M2 is secured in a mortise at its articulation with C2, and is held in a recessed position between C1 and C3. Due to this mortise, the base of M2 has a small proximal, lateral articulation with C1 (Gallagher et al.

2013, DiDomenico et al. 2012, Myerson et al. 2009, Sherief et al. 2007, Englanoff et al.

1995). This articulation is the site of the stabilization between the medial and central rays of the foot, and the site of the aforementioned “Lisfranc injuries.”

At the articulation between the medial and central rays, connecting ligaments exist in the same dorsal, interosseous, and plantar pattern observed along the entire tarsometatarsal joint. Here, the dorsal and interosseous ligaments each have a single band that extends between C1 and M2, while the plantar ligament has two bands that reach from C1 to attach to both M2 and M3 (Figure 1, Figure 2) (DiDomenico et al. 2012,

Hatem 2008, De Palma et al. 1997).

Dorsal

Plantar

Figure 2. Cross sectional schematic of the Lisfranc ligaments. The dorsal (blue), interosseous (green), and plantar (red) Lisfranc ligaments connect C1 to M2 and M3

In current literature, there is a further lack of consensus regarding the term

“Lisfranc ligament.” Some authors reference all three ligaments between C1 and M2 as the plural “Lisfranc ligaments” (Kaicker et al. 2016, Johnson et al. 2008), while others identify either the interosseous Lisfranc ligament (ILL) (Panchbhavi et al. 2013, Hirano et al. 2013, Woodward et al. 2009, DeOrio et al. 2009, Kaar 2007, Sherief et al. 2007), or the plantar Lisfranc ligament (PLL) (Gallagher et al. 2013, DiDomenico et al. 2012,) as the singular “Lisfranc ligament.” Despite the variances in definition, a consensus is apparent regarding the strength of the respective ligaments, with the plantar and interosseous ligaments being stronger and thicker than the dorsal ligament. This study will regard all ligaments attaching C1 and M2 as plural Lisfranc ligaments, due to clinical considerations of “Lisfranc injuries” and the prevalence of the concurrent injury to all three ligaments. Collectively, the DLL, ILL, and PLL, as well as C1, M2, and M3, will be referred to as the “Lisfranc joint complex.”

2.2: Lisfranc Injuries

The term “Lisfranc injury” has a more established definition than its associated joint and ligament definitions and encompasses a wide range of injuries. These include fractures, dislocations, and ligament sprains or tears. Lisfranc injuries are relatively uncommon and occur at a rate of 1 in 55,000 yearly (Hardcastle et al. 1982), accounting for 4% of all injuries in American football (Meyer et al. 1994), and for only 0.2% of all fractures (Crim 2008). However, as diagnostic techniques for Lisfranc injuries improve, the incidence of these injuries is increasing (Lewis et al. 2016). It is estimated that 20% of Lisfranc injuries are misdiagnosed or overlooked owing to the subtlety of the ligamentous injuries at this site, as well as the common concurrence of metatarsal fractures that provide more evident symptoms than the purely ligamentous form of the

Lisfranc injury (Lewis et al. 2016).

Mechanism of Injury

Classically, Lisfranc injuries are described to occur in high-energy or low-energy situations, with the high-energy situations accounting for 67% of all Lisfranc injuries

(Philbin et al. 2003). High-energy Lisfranc injuries often occur in automobile accidents or crush situations (Lewis et al. 2016, Welck et al. 2015), and may involve injury to other ligaments and bones at the Lisfranc joint (Hardcastle et al. 1982). Approximately 72% of all Lisfranc injuries involve all five tarsometatarsal joints, 69% involve both osseous and

10 ligamentous injury, and half of these injuries also involve cuneiform and/or cuboid injury

(Kuo et al. 2000).

Low-energy Lisfranc injuries, representing only one-third of all Lisfranc injuries

(Welck et al. 2015), are more common in sports. Low-energy injuries occur when an axial load is placed on a plantarflexed foot, with or without abduction (Lewis et al. 2016,

Welck et al. 2015, Philbin et al. 2003, Figure 3). Many patients reported this mechanism of injury while wearing a cleated shoe, when the foot was planted and a quick turn was attempted (Lewis et al. 2016, Meyer et al. 1994). In this scenario, the abduction force was generated by the cleats, which were anchored in the ground. Although acquired through a different scenario, extreme plantarflexion was also part of the mechanism of injury for the original patients treated by Jacques Lisfranc.

Figure 3. Mechanism of low-energy Lisfranc injury. The foot is placed in a plantarflexed position (a), with a greater than 90-degree angle between the dorsum of the foot and tibia (red), distributing an axial load through M1 and the Lisfranc joint complex (blue arrows). The plantarflexed foot may be in a rectus position (b), with a 180-degree angle from the talus to first distal phalanx (yellow), or may be placed in an abducted position (c). Abduction of the forefoot increases the talus – distal phalanx angle beyond 180 degrees (green), and generates an abducting force through the Lisfranc joint complex (blue arrow)

While low-energy injuries are infrequent, they are more commonly overlooked.

Low-energy injuries tend to be subtle, are typically closed, and purely ligamentous. High- energy injuries, on the other hand, often involve open injury to the foot, as well as concurrent fractures and the threat of compartment syndrome, which may lead to immediate medical treatment (Hardcastle et al. 1982).

While many physicians and researchers classify Lisfranc injuries based on the mechanism of injury, they can also be classified based on injury type rather than the injuring force (Hardcastle et al. 1982). This classification system examines the incongruity of the Lisfranc joint and can also be useful when the injury involves structures outside the Lisfranc joint complex. Such incongruities may be total, partial, or divergent. In a total incongruence injury, all the metatarsals have been displaced in a single plane along the Lisfranc joint. Partial incongruity may occur as either a medial displacement of the first metatarsal in isolation, or as lateral displacement of any of the remaining four metatarsals. In divergent displacement, the first metatarsal is displaced medially and at least one of the remaining metatarsals is displaced laterally (Hardcastle et al. 1982). Subtle Lisfranc injuries result in partial incongruity and medial displacement of the first metatarsal, due to the involvement of the dorsal, interosseous, and plantar

Lisfranc ligaments.

A key component of the functional stability of the Lisfranc joint complex is due to the mortise, or recessed position of the second metatarsal relative to the other metatarsals.

In more than half of patients with a ligamentous Lisfranc injury, a smaller ratio of foot length to second metatarsal length was present (Gallagher et al. 2013). Additionally,

12 studies have demonstrated that patients who experience Lisfranc injuries tend to have a shallower mortise of the second metatarsal, suggesting that this is a predisposing factor to injury (Peicha et al. 2002).

Diagnosis

The majority of athletically obtained Lisfranc injuries are closed. These patients present with pain, swelling, and tenderness over the Lisfranc joint and do not have any obvious disruption or displacement of the metatarsals (Welck et al. 2015). For this reason, these injuries can be easily overlooked when compared to the high-energy injuries, which tend to have fractures and obvious displacement of the bones. Often, plantar ecchymosis is present, which is a strong indicator of injury to the joint complex

(Welck et al. 2015), but often is not present until several days following injury (Lewis et al. 2016). Therefore, if the patient seeks medical attention immediately following the injury, this strong indicator of a Lisfranc injury is not yet present.

While standard, non-weight bearing anteroposterior, lateral, and 30-degree oblique radiographs are standard of practice, they do not place stress on the joint complex that is necessary for diagnosis. The most commonly utilized diagnostic tool for low- energy Lisfranc injuries is a weight bearing radiograph. However, this method is only effective when comparing the symptomatic foot to the patient’s asymptomatic foot. When comparing bilateral radiographs, it is important to look for a diastasis between the first and second metatarsal, as well as the loss of longitudinal arch height (Lewis et al. 2016).

Furthermore, a “fleck sign” is indicative of an avulsion fracture of the second metatarsal

13 or medial cuneiform and is reported to be present in 90% of subtle Lisfranc injuries

(Myerson et al. 2009).

Though it is the gold standard for diagnosis, several issues exist with the use of weight-bearing radiographs in patients with suspected Lisfranc injuries. Placing weight on the injured foot can cause the patient significant discomfort and as many as 37.5% of patients are unable to place weight on the injured foot at the time of diagnosis (Meyer et al. 1994). The pain that a patient experiences during weight bearing radiographs can lead to insufficient weight placement through the injured joint during imaging. This often results in negative identification of a diastasis, and the injury may go overlooked.

Likewise, abduction stress radiographs, which have been shown to be more effective in diagnosing Lisfranc injuries than weight-bearing radiographs (Kaar 2007), cause patients significant discomfort. These radiographs often require anesthesia to be obtained, and are used only as a last resort.

When fractures are involved in the injury, Computed Tomography (CT) images can be useful in defining the fractures (Lewis et al. 2016). Additionally, Magnetic

Resonance (MR) imaging can be used to visualize the ligaments and determine their integrity, as well as identify nondisplaced fractures or avulsions (Gupta et al. 2008).

However, MR imaging is costly and neither CT nor MR imaging permits weight bearing.

Weight bearing images are essential in diagnosing Lisfranc injuries. Weight bearing during diagnostic imaging is key in determining the stability of the injury, which is used to establish a treatment plan for the patient. For these reasons, CT and MR images are not often used to diagnose subtle Lisfranc injuries.

Injury Treatment

When determining the best method of treatment for Lisfranc injuries, it is important to consider the stability of the injury. Unstable, displaced injuries require surgery, which is typically an open reduction and internal fixation (ORIF). An injury is typically defined as unstable when a diastasis of 2 or more millimeters is present between the first and second metatarsals (Kaar 2007). Unstable Lisfranc injuries can occur through either high- or low-energy mechanisms. Stable, nondisplaced injuries – which are typically more subtle injuries that can be easily overlooked – are usually treated through cast immobilization and little to no weight bearing (Philbin et al. 2003). Patients are placed in short-leg cast or walking boot for a period of two to eight weeks (Lewis et al. 2016, Welck et al. 2015, Philbin et al. 2003). Serial radiographs are necessary to determine the joint complex’s healing (Lewis et al. 2016).

After a period of non-weight bearing, the patient may begin weight bearing in an orthotic device for another four weeks, if pain is still present. Once the patient is no longer experiencing pain, the patient can begin rehabilitation and gradual return to activity (Welck et al. 2015).

Patient Outcomes

Lisfranc injuries are frequently accompanied by sequelae. This can be attributed to the frequently delayed diagnosis of the injury and the nature of the injury itself. These complications can include progressive deformity, instability, and arthritis. For patients who are treated conservatively, 60% had bone irregularity and exostosis associated with

15 arthritic changes to the joint (Brunet et al. 1987). In patients who underwent open reduction and internal fixation, reports of arthritis range from 25 – 94%, and due to the joint degeneration, these patients often require secondary arthrodesis of the joint (Welck et al. 2015, Kuo et al. 2000). Broken screws have also been reported in 25% of patients who underwent ORIF (Kuo et al. 2000).

With 20% of subtle Lisfranc injuries misdiagnosed or overlooked, many patients do not receive proper treatment and experience complications. It has been demonstrated that a short period of immobilization rapidly following injury – even just one to two weeks – can speed the patient’s recovery (Lewis et al. 2016), and that surgery, when required, is most effective when completed within 24 hours of injury (Philbin et al.

2003). The improved outcomes that are observed following immediate treatment further emphasize the need for improved, more effective diagnostic techniques. Even if patients are correctly re-diagnosed and properly treated following misdiagnosis, their injury outlook is worse due to the initial delay of diagnosis. It has been shown that delay in treatment of more than six months significantly influenced patient outcomes and when surgery is completed more than six months from injury, patients require fusion at the tarsometatarsal joint (Calder et al. 2004).

Upon diagnosis, patients with borderline unstable Lisfranc injuries can opt to try conservative treatment initially, but these patients frequently experience re-displacement, severe osteoarthritis, and significant pain that require subsequent surgery and joint fixation (Hardcastle et al. 1982). Thus, it is not recommended to attempt open reduction

16 more than 6 weeks post-injury. If more than six weeks separate the time of injury and time of diagnosis, joint fixation is recommended (Philbin et al. 2003).

In subsequent follow ups, patient outcomes are variable. Most patients progress to reach a stable level between 11 months to 1.3 years following injury (McHale et al. 2016,

Brunet et al. 1987). Typically, 80% of patients can return to their original occupation, but studies report that 52% of patients who acquire Lisfranc injuries on the job pursue legal action and compensation claims (Brunet et al. 1987, Calder et al. 2004). Additionally,

28% of patients classified with “poor outcomes” required a change in employment or were unable to find employment as a result of their injury (Calder et al. 2004). When evaluated and given an American Orthopedic Foot and Ankle Society (AOFAS) Midfoot

Score, patients have an average score of 72 - 77 points (Richter et al. 2002, Kuo et al.

2000). The AOFAS Midfoot Score is an ability ranking that assesses a patient’s pain, function, and alignment. The scale ranges from 29 – 100, with a score of 100 representing the absence of foot or ankle disorders (Richter et al. 2002). Patients whose injuries are purely ligamentous have lower AOFAS and Musculoskeletal Function Assessment

(MFA) scores than patients whose injuries had osseous involvement (Kuo et al. 2000).

More than a decade after initial injury, radiographs demonstrate that 30% of patients present with a persistent diastasis between the first and second metatarsals of 4 –

10 mm, indicating a lack of full anatomic reduction (Brunet et al. 1987). Patients with the best outcomes for Lisfranc injuries have stable anatomic reduction (Kuo et al. 2000).

Deformities of the foot are reported, with planus and planovalgus deformities occurring in 30% of patients, and cavus deformities in 6% of patients (Brunet et al. 1987).

Furthermore, these deformities, as well as arthritic changes to the joint, limit the footwear options for these patients (Brunet et al. 1987).

2.3: Ultrasound imaging of the Lisfranc joint complex

The DLL, which is often described as being “flat” and “ribbon-like”, is the most commonly ruptured ligament of the Lisfranc joint complex, due to its inability to withstand tensile forces (Hardcastle et al. 1982). Due to the relative weakness of the

DLL, as well as its superficial location, it has been suggested to be indicative of the integrity of the joint complex as a whole (Graves et al. 2014, Marshall et al. 2013,

Woodward et al. 2009). A ruptured DLL would appear in ultrasound as a disruption in the hyperechoic bands within the ligament and edema would also be present (Lento et al.

2008).

In vivo, studies have demonstrated the ease of visualization of the DLL through the use of ultrasound, demonstrating its clinical use in determining the integrity of the joint (Woodward et al. 2009), its response under varying weight and positional stresses

(Graves et al. 2014), and its bilateral symmetry in normal patients (Marshall et al. 2013).

When the DLL could not be visualized during ultrasound procedures, it was indicative of rupture of the DLL, as well as injury to the ILL (Woodward et al. 2009). Thus, diagnosing an injury to the Lisfranc joint may be simplified by using ultrasound to compare the symptomatic and asymptomatic DLLs.

Diagnosing subtle Lisfranc injuries can be difficult. Weight-bearing x-rays can be an excellent diagnostic tool, but can be problematic. Such x-rays may cause the patient

18 significant discomfort and may not accurately reflect the integrity of the joint complex if sufficient weight cannot be placed on the injured foot (Shereif et al. 2007, Englanoff et al.

1995, Meyer et al. 1994). Ultrasonography can easily be utilized in such scenarios and can be done with minimal discomfort to the patient. The foot is placed in a neutral position and due to its superficial location, the dorsal Lisfranc ligament can be quickly identified and its integrity determined.

Ultrasonography machines are available in most emergency room and orthopedic offices and with the proper training, can be used to examine potential Lisfranc injuries

(Bica et al. 2015). This would be beneficial to both the patient and physician – quick visualization of the ligament helps the physician to begin the proper treatment and the patient does not need to bear weight on an injured joint complex.

In the majority of the literature, the Lisfranc joint complex is partially visualized with sonography from the dorsal aspect of the foot (Ryba et al. 2016, Graves et al. 2014,

Ibrahim et al. 2014, Rettedal et al. 2013, Marshall et al. 2013, Woodward et al. 2009).

From the dorsal view, the surfaces of C1 and M2 are easily seen, and the DLL can be identified connecting them. The ILL, due to its location between the bones, cannot be visualized from this view, nor can the PLL.

Protocol for imaging the PLL has been described, particularly by referencing its position relative to the peroneus longus tendon (Ansede et al. 2010). However, due to the density of musculature on the plantar aspect of the foot, and the edema that would be present in Lisfranc injuries, the plantar view of the Lisfranc joint complex is not practical

19 in the clinical setting. Therefore, a dorsal approach to visualizing the Lisfranc joint complex remains the best option when diagnosing Lisfranc injuries with ultrasonography.

2.4: Cadaveric Studies involving the Lisfranc Joint

Cadaveric studies have been performed in an effort to better characterize the

Lisfranc joint complex and clarify its diagnosis in a clinical setting. Previous cadaveric studies have mapped the attachments areas, lengths and thickness of the interosseous

Lisfranc ligament (Panchbhavi et al. 2013), and developed computer-mapped models of the joint complex under approximately 50% body weight (Panchbhavi et al. 2008). Other studies have used dissection to measure the joint space between C1 and M2 rather than the involved Lisfranc ligaments (Yu-Kai et al. 2015).

Furthermore, cadaveric models have been utilized primarily to evaluate the surgical methods available for Lisfranc stabilization and fixation, as well as the joint’s subsequent stability (Alberta et al. 2005, Kadel et al. 2005, Lee et al. 2004, Kura et al.

2001, Solan et al. 2001). Other studies have utilized cadaveric specimens in the comparison of the Lisfranc ligaments in MR Imaging (Kitsukawa et al. 2015, Delfaut et al. 2002) and CT imaging (Lu et al. 1997) to subsequent gross dissection.

2.5: Current Study

The majority of literature regarding the Lisfranc joint and its ligaments review the diagnostic imaging and treatment protocol in relation to injury to the aforementioned structures. To date, one study has reported on the ultrasound appearance of the DLL and

20 correlated these images with its surgical appearance (Woodward et al. 2009). However, most subtle Lisfranc injuries are treated conservatively and the opportunity to compare ultrasound and in vivo appearances of the DLL is rare. Thus, a unique comparison was sought through the use of cadaveric specimens, which provide examples of uninjured

Lisfranc ligaments. Such a study is relevant because it provides a population of patients with uninjured, normal Lisfranc ligaments that can be characterized through multiple methods in order to help synthesize and develop a better understanding of the anatomy of the structures involved in such a frequently missed diagnosis.

Additionally, ultrasound of the DLL has been advocated as a diagnostic tool in the clinical setting (Woodward et al. 2009). In order to advocate the use of this method in practice, data is necessary to demonstrate the accuracy of the measurements that are provided through ultrasonography. The current study provides evaluative methods for the precision of ultrasonography in measuring the DLL by comparing the measurements of the images obtained through ultrasound to the gross measurements of the cadaveric specimens. Additionally, morphologic characteristics of the entire Lisfranc joint complex were observed in gross dissection to further characterize the uninjured joint.

Chapter 3: Methods

With the permission of The Ohio State University’s Body Donation Program, 22 embalmed cadavers were sought for use in this study, without preference for age or sex.

Each cadaver was assigned a random identification number (LF01 – LF22). The right foot of each cadaver was used for both the ultrasound measurements and the dissection measurements.

Prior to ultrasound and dissection, anthropometric measurements of each foot were obtained. These measurements included the total foot length from calcaneus to the most distal phalanx, medial foot length from calcaneus to the head of M1, lateral foot length from the calcaneus to the head of M5, and width of the foot between M1 and M5

(Figure 4a-d).

Figure 4. Anthropometric measurements of the foot. Measurements included: (a) total foot length, (b) foot length to the first metatarsal head, (c) foot length to the fifth metatarsal head, and (d) foot width between first and fifth metatarsal heads. Guidelines (black lines in images) were palpated and drawn on to represent the cuneonavicular as well as the first and second tarsometatarsal joints

3.1: Ultrasound Methods

For the ultrasound evaluation, a 6-13 MHz linear probe was used on a Sonosite

M-Turbo ultrasound unit (FUJIFILM SonoSite, Inc, Bothell, WA). The musculoskeletal

(“MSK”) settings were selected for use. The depth of the ultrasound beam was set for 1.8 cm and standard ultrasound gel was used for each scan. The first and second tarsometatarsal joints and the cuneonavicular joints were palpated on each foot, and their locations were marked on the dorsum of the foot with a permanent marker (Figure 5).

These marks were used as a guideline for probe placement.

Figure 5. Initial probe placement on the dorsum of the foot. After identifying the first and second metatarsals in the ultrasound image, the probe was moved proximally (arrow A) until reaching the joint guidelines (B)

The probe was placed on the dorsum of the foot with a cross-sectional orientation distal to the skin markings, with the leading edge facing medially. The shafts of the first and second metatarsals were identified (Figure 6a) and the probe was moved more

23 proximally to the articulation between the medial cuneiform and the second metatarsal

(Figure 6b-c). The dorsalis pedis artery was used as a landmark to determine the approximate location of the joint complex as the artery lies superficial to the DLL in the majority of the specimens. The probe placement was adjusted to identify the DLL (Figure

6d). Once the clearest image was in view, the image was captured, labeled and measured.

This process was repeated on the right foot of all 22 cadavers. The ultrasound scan protocol can be found in Appendix B.

C1 M1 M2 M2

DLL DLL

C1 C1 M2 M2

Figure 6. Ultrasound imaging of the dorsal Lisfranc ligament. Scanning began with identification of the shafts of M1 and M2 (a). The probe was moved proximally until C1 was visible (b). Probe placement was then gradually adjusted, with the leading edge being placed slightly proximal. Placement was adjusted (c) to bring the DLL and dorsal joint space (bracket) into view (d)

Ultrasound images for each specimen were exported from the ultrasound unit, and were uploaded onto a laptop computer where analysis was completed with ImageJ software (National Institutes of Health, Bethesda, Maryland). The scale was set to

24 measure in millimeters using the 1-centimeter depth markers on the right-hand side of the image, and was made “Global” to allow application to all analyzed images. Images were opened individually and measurements were completed at the endpoints of the DLL as well as for the dorsal joint space (Figure 7). When possible, ligament thickness was also measured at mid-substance.

Figure 7. Analysis of the dorsal Lisfranc ligament using ImageJ software. Yellow lines demonstrate the measurement of the DLL (superior) and the dorsal joint space (inferior)

3.2: Dissection Methods

Unilateral dissection was performed on each cadaver, using the previously scanned right foot. Prior to gross dissection, the cadavers were utilized for class by medical students, who removed the skin and superficial fascia and dissected the superficial tendons and muscles of the foot. Following use by the medical students, the dorsal tendon attachments were cut distally and the tendons were reflected. The peroneus longus tendon was also cut from its distal attachment on the plantar aspect of the foot.

To create an isolated view of the Lisfranc ligaments, the bones of the Lisfranc joint complex were removed en bloc. A scalpel was used to cut the soft tissue connecting

M3 and M4. This cut was continued proximally to the tarsometatarsal joint. Medially, the navicular tuberosity was palpated and just distal to that, the first cuneonavicular joint was located. The forefoot was abducted slightly to stretch the joint capsule and a scalpel was used to make an incision in the capsule. This incision was continued around the entire cuneonavicular joint capsule. Any remaining soft tissue connections were cut and C1, C2, and C3, as well as M1, M2, M3 and their associated phalanges were removed en bloc

(Figure 8a). M1 was removed from the bloc first. The soft tissue connecting M1 and M2 was cut with a scalpel and the joint capsule of the first tarsometatarsal joint was cut to remove M1 (Figure 8b). Next, the second and third tarsometatarsal joint capsules were cut and C2 and C3 were removed. This left only C1, M2, and M3 in the bloc (Figure 8c).

Specimens were stored in sealed gallon storage bags containing embalming fluid to treat dehydrated tissue.

M1 M2 M3 M2 M3 M2 M3 C1 C2 C1 C3 C1 C2 C3

Figure 8. En bloc dissection of the medial and central rays of the foot. Dissection began with the removal of the three cuneiforms, first through third metatarsals, and their associated phalanges (a). The first metatarsal was then removed (b), as were the intermediate and lateral cuneiforms (c), leaving only the bones of the Lisfranc joint complex: the medial cuneiform, second metatarsal, and third metatarsal

From the isolated specimens, the DLL and ILL were identified running between

C1 and M2, while the PLL was identified running from C1 to M2 and M3. The ligaments were measured using electronic calipers (General Tools & Instruments, Secaucus, New

Jersey). For the DLL and ILL, each ligament’s length, width, and thickness were measured at mid-substance. For the PLL, the distance from the origin on C1 was measured to each of the insertions on M2 and M3. Additionally, measurements were obtained from the bifurcation of the PLL toward each of its insertions. Measurements were also taken of the medial C1 – M2 mortise depth and the length of M2. Dissection protocol can be found in Appendix C.

3.3: Analysis

To assess the accuracy of in-unit measurement, Sonosite M-Turbo and ImageJ measurements of DLL length and dorsal joint space were compared through a one-sample t-test. Both ultrasound measurements were then compared to dissection measurements of

DLL length, dorsal joint space, and DLL thickness through one-sample t-tests. The one- sample t-tests were performed to calculate the percentage of true DLL length that was represented in ultrasound, thus providing a ratio of ultrasound measurement to dissection measurement. Differences across the three measurement modalities were assessed using a one-way ANOVA. All statistical comparisons were completed using SPSS Version 25

(IBM, Armonk, New York). Additionally, descriptive statistics were completed for the gross dissection measurements of the dorsal joint space, DLL, ILL, and PLL length, width, and thickness, as well as for the anthropometric measurements of the foot, including medial mortise depth and M2 length.

Anthropometric measurements of the foot were used to identify potential correlations between foot morphology and DLL morphology. Pearson product-moment correlations were performed to examine any association between the DLL dissection length to the M2 length, medial mortise depth, foot length to distal phalanx, medial foot length to M1 head, lateral foot length to M5 head, and foot width between M1 and M5 heads. Furthermore, comparisons of male and female DLL lengths were completed using a Welch two sample t-test. For all statistical tests, significance was set a priori at p <

0.05.

Chapter 4: Results – Ultrasonography of the Dorsal Lisfranc Ligament

Twenty-two specimens were scanned and measured. However, upon further

evaluation, four specimens had to be excluded from data analysis, as the data and tissue

were not of sufficient quality for analysis (specimens LF04, LF05, LF07, and LF13).

Eighteen specimens were included in analysis with a mean age of 80.33 ± 14.08 years.

Mean anthropometric measurements can be found in Table 1 and raw anthropometric

data can be found in Appendix A, Table 13. The mean DLL length was larger in

dissection than in either ultrasound measurement, as shown in Table 2. Individual DLL

measurements are in Appendix A, Table 14.

Table 1. Mean anthropometric measurements of the foot

Calcaneus Calcaneus Calcaneus Medial – distal M1 – M5 M2 n = 18 Age – M1 head – M5 head mortise phalanx width length length length depth length Average 80.33 251.5 191.8 175.1 94.11 84.39 10.52 SD 14.08 16.36 11.55 9.18 7.73 4.06 1.04

Table 2. Mean measurements of the DLL across modalities

Sonosite M-Turbo ImageJ Dissection Dorsal Dorsal Dorsal n = 18 Length Joint Length Joint Thickness Length Joint Thickness Width Space Space Space Average 8.39 2.19 8.25 2.05 4.39 10.80 1.04 1.36 8.30 SD 1.27 0.49 1.84 0.52 1.38 1.85 0.24 0.42 1.49

The ratio of the difference between the Sonosite M-Turbo and ImageJ measurements to the dissection measurements was not significantly different from 0, as shown in Figure 9 (p-value = 0.585) (Table 3). The ratio of Sonosite M-Turbo measurements and dissection measurements of the DLL length were significantly below

1 (p-value < 0.001) (Figure 9, Table 3). The ratio of ImageJ measurement and dissection measurement of the DLL length was significantly below 1 (p-value < 0.001) (Figure 9,

Table 3).

Figure 9. Comparison of mean DLL length between modalities. Comparisons included Sonosite M- Turbo vs. ImageJ (a), Sonosite M-Turbo vs. Dissection (b), and ImageJ vs. Dissection (c). Differences indicated with * were statistically significant (p-value < 0.001)

Table 3. One sample t-tests comparing DLL measurement ratios across modalities

One sample t-test t df p-value 95% CI Sonosite M-Turbo 19.45 17 < 0.001 (0.71, 0.88) Dissection ImageJ 19.46 17 < 0.001 (0.69, 0.86) Dissection (ImageJ-Sonosite M-Turbo) -0.56 17 0.585 (-0.09, 0.05) Dissection

Mean DLL thickness as measured with ImageJ software was larger than the mean thickness in dissection. The difference between thickness measurements was significant

(p < 0.05) (Figure 10, Table 4).

Figure 10. Comparison of DLL thickness between modalities. The difference between ImageJ and dissection measurements of DLL thickness was significant (p-value < 0.05), as indicated by *

Table 4. One sample t-test of DLL thickness ratio

One sample t-test t df p-value 95% CI ImageJ 6.83 10 < 0.001 (2.29, 4.52) Dissection 31

The mean dorsal joint space measurements were larger in ultrasound measurements than in dissection measurements. Differences in dorsal joint space measurement were significant between Sonosite M-Turbo and dissection measurement

(p-value < 0.001) (Figure 11, Table 5). Measurement differences of the dorsal joint space in ImageJ and dissection were statistically significant (p < 0.001) (Figure 11, Table 5).

Sonosite M-Turbo and ImageJ measurements of the dorsal joint space were not statistically different (p-value > 0.05) (Figure 11, Table 5).

Figure 11. One sample t-tests of dorsal joint space across modalities. Comparisons included Sonosite M-Turbo vs. ImageJ (a), Sonosite M-Turbo vs. Dissection (b), and ImageJ vs. Dissection (c). Differences indicated with * were significantly different (p-value < 0.001)

Table 5. One sample t-tests for comparison of dorsal joint space across modalities

One sample t-test t df p-value 95% CI Sonosite M-Turbo 16.08 16 < 0.001 (1.93, 2.52) Dissection ImageJ 15.86 16 < 0.001 (1.83, 2.39) Dissection (ImageJ-Sonosite M-Turbo) -0.99 16 0.34 (-0.35, 0.13) Dissection

Chapter 5: Results – Dissection of the Lisfranc Joint Complex

Of the 22 subjects that were initially obtained for the purposes of this study, 20 feet underwent en bloc dissection to isolate the Lisfranc joint complex and 18 underwent successful dissection of the Lisfranc ligaments. One specimen did not undergo ILL or

PLL dissection due to poor bone quality, and two specimens did not have ILL dissection due to bony outgrowths of C1 that disrupted the ligament. The ligament morphology was observed. For all ligaments, length was defined as the distance, in millimeters, from the ligaments proximal origin to its distal insertion. The width of the ligament was defined relative to the dorsal view of the ligament. Considering the oblique path of the Lisfranc ligaments, the width was measured, in millimeters, from the anteromedial side of the ligament to the posterolateral side of the ligament. Finally, ligament thickness was measured as the distance, in millimeters, between the dorsal surface of the ligament and the plantar surface of the ligament. All measurements were completed in millimeters and taken at mid-substance of the respective ligaments.

All of the dissected DLLs originated on the dorsal surface of C1 and inserted on the dorsal surface of M2. The origin was more proximal than the insertion, resulting in a slightly oblique placement of the ligament (Figure 12). The mean measurements of DLL length, width, thickness, and dorsal joint space are shown in Table 6. Raw data for these measurements can be found in Appendix A, Table 13.

Figure 12. Dissection of the DLL. The DLL connects the dorsal surfaces of C1 and M2. Also visible is the M3

Table 6. Mean gross measurements of the DLL

n = 18 Length Dorsal Joint Space Thickness Width Average 10.80 1.04 1.36 8.30

SD 1.85 0.24 0.42 1.49

For the ILL, length and thickness of the ligament were obtained for 15 of the dissected specimens. The mean length was 9.70 ± 2.04, and the mean thickness was

13.74 ± 3.08. Ligament width was obtained for 7 of the dissected specimens. The remaining 8 ILLs possessed connections to the PLL that prevented measurement of the

ILL width in isolation. The mean ligament width for the measured specimens was 1.66 ±

1.08 (Table 7). Complete measurements of the ILL can be found in Appendix A, Table

14.

Table 7. Mean gross measurements of the ILL

Length Width Thickness n 15 7 15

Average 9.70 1.66 13.74 SD 2.11 1.08 3.08

The PLL demonstrated more variable morphology than either the DLL or ILL.

Upon dissection, it was noted that the PLL presented with two shapes. The most common shape of the ligament, observed in 14 of the dissected specimens, was fan-shaped or triangular (Figure 13). In this variant, the apex of the ligament was located on the medial cuneiform, and the ligament extended distally, widening to insert across the plantar surfaces of M2 and M3. At no point did these ligaments bifurcate into separate bands to the involved metatarsals. Additionally, 9 of the specimens that demonstrated this morphology also had connections between the ILL and PLL (Figure 13). The remaining specimens had a distinct separation between the ILL and PLL (Figure 14). The mean ligament length, width, and thickness can be found in Table 8, and complete measurements of the gross PLL fan variant are in Appendix A, Table 15.

Figure 13. Dissection of the PLL fan variant. The specimen also possessed a connection between the ILL and PLL

Figure 14. Dissection of the ILL and PLL. The specimen demonstrates complete separation of the ILL and PLL, which was seen in 6 specimens

Table 8. Mean gross measurements of the PLL fan variant

C1 – M2 C1 – M3 Proximal n = 14 Distal Width Thickness Length Length Width Average 13.27 12.72 5.89 8.83 2.03 SD 2.52 1.98 1.89 2.04 0.71

The PLL also demonstrated split morphology in 3 specimens. For two of these specimens, the ligament possessed a single origin that bifurcated distally to extend separate insertions on M2 and M3 (Figure 15). One of these ligaments also possessed a connection to the ILL. The third specimen that demonstrated split morphology of the PLL possessed two bands that began separately on C1 and inserted separately on M2 and M3, respectively (Figure 16). The band that extended to M2 was larger than the band to M3, and possessed a connection to the ILL. Due to the split morphology, additional measurements were obtained for these three split variants.

Figure 15. Dissection of the PLL split morphology. The PLL also demonstrates a separation from the ILL

Figure 16. Morphological variant of the PLL. The PLL in LF16 possessed two bands that began separately on C1, and inserted on M2 and M3. The M2 band also was found to be continuous with the ILL

For the PLL split morphology, additional gross measurements were completed.

Mean measurements of the PLL variant with split morphology can be found in Table 9,

and complete measurements are found in Appendix A, Table 16.

Table 9. Mean gross measurements of the PLL variant with split morphology

Length Width Thickness n = 3 C1 – C1 – C1- Bifurcation Bifurcation C1- M2 M3 C1 – M2 M3 M2 M3 Bifurcation – M2 – M3 Bifurcation Insertion Insertion Bifurcation Insertion Insertion

Average 14.08 13.82 10.38 5.72 6.13 5.14 3.87 4.59 1.345 1.45 0.98

SD 3.00 1.38 1.74 0.13 1.36 0.93 0.88 2.49 0.33 1.23 0.32

Despite sharing a common function – connecting C1 and M2, the lengths of the

ILLs and the C1-M2 bands of the PLL fan variant differed. Both the ILL and the C1-M2 band of the PLL had an oblique orientation, extending from a proximal origin on C1 to a distal, more lateral insertion on M2. The mean length of the ILL was 9.70 mm, with a range of 4.13 – 12.81 (Figure 17). The C1-M2 band of the PLL fan variant, on the other hand, had a mean length of 13.27 mm, and a range of 9.6 – 18.16 (Figure 17). The PLL split variant had a C1 – M2 band with a mean length of 14.04 mm (Figure 17).

Figure 17. Comparison of ILL and PLL fan variant length to M2 insertion. ILL length was 9.70 mm and the range was 4.13 – 12.81 mm. Mean C1 – M2 band length in the fan variant was 13.27 mm, with a range of 9.6 – 18.16 mm

When mean DLL length in dissection was compared to anthropometric measurements of the foot, no correlations were found (Table 10). Furthermore, comparisons of mean DLL length in dissection were not significantly different between male and female specimens.

Table 10. Correlation of anthropometric measurements of the foot to gross DLL length

Pearson's product-moment correlation Correlation t df p-value 95% CI Coefficient M2 Length 0.13 16 0.90 (-0.44, 0.49) 0.03 Medial 0.57 15 0.58 (-0.36, 0.59) 0.15 Mortise Depth Calcaneus - 0.71 16 0.49 (-0.32, 0.59) 0.17 Hallux Length Heel - M1 0.43 16 0.68 (-0.38, 0.55) 0.11 Length Heel - M5 0.14 16 0.89 (-0.44, 0.49) 0.04 Length M1 - M5 -0.21 16 0.84 (-0.51, 0.43) -0.05 Width

Figure 18. Sex differences in gross DLL length. Differences were not significant (p > 0.05)

Table 11. Sex differences in gross DLL length

Welch two sample t-test t df p-value 95% CI Female/Male -1.06 15.63 < 0.001 (-2.50, 0.83)

Chapter 6: Discussion

6.1: Ultrasound Imaging

The primary objective of this study was to determine the efficacy of ultrasound imaging of the Lisfranc joint complex. The study sought to do this by obtaining ultrasound images and measurements of the DLL by two different methods and comparing them to measurements of the ligament in gross dissection. This component of the study was quantitative. The results of this component supported the study’s alternative hypothesis, demonstrating that the ultrasound measurements of the DLL were significantly different from the dissection measurement of the DLL. Also, ultrasound measurement of the DLL with Sonosite M-Turbo and ImageJ were not significantly different from each other, supporting the null hypothesis of the study’s ultrasound comparison.

Differences in the mean DLL length measurements on the ultrasound unit and using ImageJ software were not significant (p = 0.585), indicating that measurement between the modalities was relatively consistent. On the contrary, differences in ligament length were significantly different when comparing ultrasound unit and dissection measurements, as well as ImageJ and dissection measurements (p-values < 0.001).

Regardless of the software used, ultrasound image measurements of the DLL underrepresented the true gross appearance of the DLL. However, this underrepresentation was regular, with the ultrasound measurements expressing 42 approximately 70-80% of the true ligament length. This finding demonstrates that although ultrasound is an efficient tool for DLL visualization, it is not one that can accurately measure the full length. However, the purpose of using ultrasound to image the DLL in diagnosis is merely to determine its integrity rather than its full geometry.

Although the measurements of the ultrasound images were significantly different from the dissection measurements, they demonstrated consistency. The measurements of the ultrasound images were completed using different software, yet their difference was not significant. This confirms the consistent appearance of the DLL in ultrasound imaging, which has been indicated in the literature (Graves et al. 2014, Rettedal et al.

2013, Marshall et al. 2013). The mean measurements obtained in ultrasound imaging were approximately 20-30% smaller than the mean measurements acquired in dissection.

Mean DLL length in ultrasound was 8.39 mm (Sonosite M-Turbo) and 8.24 mm

(ImageJ), while mean DLL length in dissection was 10.8 mm. This measurement difference is likely due to difficulty distinguishing the true origin and insertion of the

DLL on the bones in the ultrasound images. Additionally, the mean DLL thickness and dorsal joint space measurements were significantly different between imaging and dissection. However, these differences were consistent, and unlikely to be consequential in diagnosis of subtle Lisfranc injuries, as the use of ultrasound seeks to determine the ligament’s integrity rather than its geometric characteristics. Based on these findings, it can be reasoned that ultrasound is an effective, yet metrically inaccurate, method of evaluation for the DLL.

6.2: Cadaveric Dissection

The secondary objective of this study involved the gross dissection of the Lisfranc joint complex to provide descriptions of its morphology. A novel dissection technique was developed and successfully utilized to dissect 20 of the 22 original specimens, obtaining measurements of the DLL from 18 specimens, measurements of the ILL in 15 specimens, and measurements of the PLL in 17 specimens.

Gross dissection in this cohort demonstrated the relative consistency of the DLL length (mean 10.8 mm ± 1.79). No variant morphology was present in the specimens, suggesting that variant DLL morphology is unlikely to be the cause of subtle Lisfranc injuries.

In current literature, several discrepancies of the PLL exist. One study (Kura et al.

2001) does not mention the existence of the PLL, while two other studies (Welck et al.

2015, Johnson et al. 2008) do not mention the PLL’s connection to M3. In the current study, connections to M3 were present in all specimens, but existed as separate ligamentous bands in only 3 specimens. Welck et al. (2015), when defining a singular

Lisfranc ligament, described a “plantar interosseous ligament”, while Yu-Kai et al.

(2015), defined a singular plantar Lisfranc ligament. However, both studies defined the objective ligaments as connecting the lateral side of C1 to the medial side of M2, and did not mention connections to M3. While terminology is inconsistent, connections between the ILL and PLL have been explicitly described (Castro et al. 2010), suggesting that the

ILL – PLL connections in 64% of specimens in the current study is not a novel finding.

Despite inconsistencies in the naming of a singular Lisfranc ligament, there is a

44 consensus that both the ILL and PLL, according to their definitions in this study, are stronger than the DLL. It is unknown whether a connection between the ILL and PLL, and/or separate M3 bands of the PLL, when present, would compromise or enhance the stability of the Lisfranc joint.

Mean ligament thickness varies between the DLL, ILL, PLL fan variant, and the

PLL split variant. As previously described in the literature (Hardcastle et al. 1982), the mean DLL thickness was less than the mean thickness of the ILL, or the PLL fan variant.

The thickest ligament was the ILL, with a mean thickness of 13.74 mm. The ILL also demonstrated the smallest width measurement, with a mean of 1.66 mm. This is due to the operational definitions that were used when measuring the ligaments. The thickness of a ligament was defined as the difference between its superficial surface and deep surface, while the width was defined relative to the ligaments’ medial and lateral surfaces. Since the ILL is contained within the Lisfranc joint, it extends the depth and width of the joint itself, giving it a much larger thickness measurement and much smaller width measurement.

6.3: Clinical Relevance

Considering the constancy of ultrasound measurements of the DLL in this study, the use of ultrasonography as a diagnostic tool for Lisfranc injuries is supported. The

DLL demonstrated a standard deviation of less than 2 mm in two different software platforms and gross dissection. The DLL length was not correlated to any of the

45 anthropometric measurements of the foot. This finding suggests that the length of the

DLL is relatively constant, despite variations in foot size.

The DLL length as measured in ultrasound imaging was consistent, with 70-80% of the total length represented. With this consistency, landmarks can be established for the use of ultrasound in Lisfranc diagnosis. Measurements of the DLL in ultrasound involved identifying the location where the DLL blended into the peaks of C1 and M2 in each image. Thus, the mean distance between bony peaks is equal to the mean measured

DLL length in ultrasound.

Clinically, an unstable Lisfranc injury diagnosis requires the recognition of a diastasis of at least 2 mm between M1 and M2 (Kaar 2007). This measurement examines the interosseous joint space between the medial and central rays of the foot. In ultrasound imaging, this joint space is poorly visualized, and a dorsal measurement of the joint space was obtained instead. However, a ≥ 2 mm spread in the interosseous joint space would cause an increase in the distance between the bony peaks of C1 and M2, as well as an increase in the dorsal joint space.

Considering this, it is possible to develop a two-component diagnosis for Lisfranc injury using ultrasonography. The first component would address the diastasis between

M1 and M2 indirectly by assessing the distance between C1 and M2 peaks. A distance between peaks that is greater than 10 mm (mean measured DLL length + 2 mm) would indicate the presence of a ≥ 2 mm diastasis. The second component of diagnosis would address the presence and integrity of the DLL. The current study has demonstrated the

46 efficiency of DLL visualization in ultrasound. The disruption or absence of a hyperechoic band between C1 and M2 would then serve as the second diagnostic component.

Previous studies have suggested a relationship between the M2 mortise depth and a predisposition to Lisfranc injury, with an increase of 1 mm in medial mortise depth reducing the likelihood of Lisfranc injury by half (Peicha et al. 2002). While associated with Lisfranc injury, the medial mortise depth was not correlated to the gross DLL length in this study. Similarly, the gross DLL length was not correlated to anthropometric measurements of the foot. These data indicate that the DLL length is independent of foot metrics. This finding further highlights the complex nature of Lisfranc injuries, and demonstrates why injury prevention and treatment is often complicated.

When measured between two different platforms and separate raters, the ligament demonstrated minimal variations in length, with a mean DLL length of 8.39 mm for the in-unit measurements, and a mean DLL length of 8.24 mm for the ImageJ measurements.

In addition, minimal variations were noticed in the dorsal joint space, with the mean width in-unit measuring at 2.19 mm and mean width in ImageJ measuring at 2.05 mm.

The difference between the DLL length measurements in ImageJ and the ultrasound software were not significant. This coordinates with previous findings in the literature, which demonstrated the consistent representation of the DLL within and between raters

(Rettedal et al. 2013).

Measurements of the ILL and PLL were not obtained in two separate specimens due to the presence of bony outgrowths on the medial cuneiform. With reports of arthritis following injury of the Lisfranc joint as high as 94% (Welck et al. 2015), this finding

47 raises questions regarding the prevalence of arthritis in an uninjured Lisfranc joint.

Additionally, the variability of the PLL that was observed in dissection may coordinate to injury to the Lisfranc joint complex, or to the variable outcomes that patients face.

In the literature, the DLL is described as a flat, ribbonlike ligament, and is reported to be more commonly ruptured than the ILL and PLL due to this morphology.

The appearance of the DLL in this study matches this description, and its observed small thickness (mean = 1.35 mm). Due to the thin nature of the DLL, it can be reasonably inferred that the DLL would be more likely to rupture than either the ILL or PLL, as was suggested by the literature (Hardcastle et al. 1982). Some studies have suggested that a higher propensity to rupture, as well as its superficial location, make the DLL a key indicator in the diagnosis of subtle Lisfranc injuries (Graves et al. 2014, Marshall et al.

2013, Woodward et al. 2009). This thesis has demonstrated the relative ease of visualization of the DLL in musculoskeletal ultrasonography, and has confirmed the morphology of the DLL. These data and measurements uphold the recommended use of ultrasound imaging to diagnose subtle Lisfranc injuries.

6.4: Limitations

The primary limitation in the study is the small sample size. A total of 22 embalmed cadaveric feet were utilized during this study and four of the specimens were not included in any analysis due to insufficient data or tissue quality (specimens LF04,

LF05, LF07, LF13). Additionally, measurements of the ILL were completed in only 15 specimens, and PLL measurement was completed in 17 specimens. Four specimens were

48 excluded following ultrasound scanning due to insufficient tissue quality, one was excluded from ILL and PLL measurement due to poor bone quality, and two ILLs were interrupted by bony outgrowths and were not measured.

Additionally, the use of two raters and two software systems in the measurement of the DLL in ultrasound imaging prevented the use of inter-rater correlational studies, as well as comparison of the measurement systems. In future studies, separate raters could use both measurement modalities to determine the inter-rater reliability of the imaging, as well as the reliability of the two software systems.

Another concern in this study was the use of embalmed cadaveric specimens.

Previous scans of the Lisfranc joint complex were referenced to examine the differences between in vivo and cadaveric scans of the DLL. In the in vivo images, the ends of the

DLL were clearly visible inserting on C1 and M2, as shown in Figure 17a. Immediately superficial to the DLL was the dorsalis pedis artery and its associated vein (Figure 19a).

Cadaveric embalming results in abnormal amounts of free fluid in the preserved tissues.

Interference of this fluid with the ultrasound imaging was anticipated based on previous cadaveric ultrasound studies (Kichouch et al. 2009), but was not observed. In the cadaveric specimens, minimal hyperechoic regions were present. As in the in vivo images, C1 and M2 were visible, as well as the ends of the DLL (Figure 19b). However, the dorsalis pedis artery and its associated vein were not visible.

Figure 19. Ultrasound imaging of the DLL in vivo and in cadavers. In both images, C1 and M2 are easily seen, as well as the ends of the DLL (white arrows). However, only the in vivo image (a) shows the dorsalis pedis artery (red arrow) and its associated vein (blue arrow). Neither are visible in the cadaveric image (b)

The use of embalmed specimens was also the source of other study limitations.

Ligament measurements may vary slightly from the in vivo length due to the rigidity of the embalmed specimens. In addition to their use in this study, the cadavers were utilized by first and second year medical students at The Ohio State University. Cadavers were skinned to the ankle prior to their use in this study, allowing much of the excess embalming fluid to drain from the tissues prior to ultrasonography. This likely resulted in the lack of fluid “noise” observed in the images. Prior to this study’s en bloc dissection, the involved feet underwent routine dissection of the foot and ankle, which included the identification and preservation of the tendons and neurovasculature of the foot. Despite efforts to preserve tissues, specimens are often exposed for extended periods of time during dissection, studying, and practical examination. This complicated the removal of some of the en bloc specimens due to drying and subsequent hardening of the tissues, which could have affected their measurement.

Furthermore, the mean age of the cadavers included in the study was 80.33 years

± 14.08, whereas literature identifies the third decade of life as the most frequent period of Lisfranc injury (Welck et al. 2015). The mean cadaver age was fifty years beyond the mean age of Lisfranc injury patients and specimens in this study were not representative of the predominant population that experiences Lisfranc injury. However, most donors to whole-body donation programs are typically elderly, so obtaining a cadaveric sample that reflects the true age of the Lisfranc injury population is not likely.

The sample in this study had 11 males and 7 females, but males are two to four times more likely to acquire Lisfranc injuries (Welck et al. 2015). In a previous study by

Calder et al. (2004), approximately 70% of the evaluated Lisfranc injury patients were male, and 36% of these male patients experienced poor outcomes, while only 7% of the female patients had poor outcomes. The higher prevalence of males who experience

Lisfranc injuries may be due to many factors. Lisfranc injuries represent 4% of all injuries in the National Football League each year (McHale et al. 2016). Thus, male athletes participate in more sports with cleated footwear, increasing their incidence of subtle Lisfranc injury. Additionally, many high-energy Lisfranc injuries, and some low- energy injuries, are obtained through falls from a height of 2 or more meters, commonly while participating in a manual labor job (Calder et al. 2004). Males are more likely to participate in manual labor jobs, and are thus more likely to experience such an injurious fall, adding to the higher observation of Lisfranc injuries among males than females.

6.5: Future work

While this thesis successfully compared ultrasound imaging of the Lisfranc joint complex to the complex’s appearance in gross dissection, improvement and expansion of the project is possible. Since a primary limitation of this study regards the use of embalmed cadavers, the use of fresh cadavers could expand the data set and allow for more comparisons. Advantages of using fresh cadavers include a lower probability of

“noise” in imaging due to the absence of embalming fluid, and mobility and tissue quality that more accurately reflect the in vivo joint complex.

Considering the difference in injury incidence based on sex, future studies could examine potential causes for this discrepancy. While the current study did not yield any significant differences between male and female DLL length, future studies could examine the factors that predispose males to Lisfranc injury. Such factors could include morphological characteristics of the foot as well as lifestyle characteristics.

The specimens in this study were uninjured, and thus represented a sample of

“normal” Lisfranc joint complexes. Ideally, future work would include induced cadaveric injury of the Lisfranc joint complex to compare the ultrasound and dissection appearance of an injured joint to what has been observed in the “normal” joint.

The presence of bony outgrowths within the Lisfranc joint complex raises questions about the prevalence of arthritis at the uninjured Lisfranc joint. A sample such as the one used in this study – elderly cadavers – could be especially useful in a study of

Lisfranc arthritis. This could allow a deeper understanding of the high rates of arthritis in those who experience Lisfranc injuries by questioning whether the high rates of arthritis

52 in these patients can be entirely attributed to their injury history, or if the aging process is partially responsible.

Finally, future work would apply the current study’s findings to a suspected

Lisfranc injury in vivo. The potential two-component ultrasound diagnostic protocol could be utilized to assess the distance between C1 and M2 peaks, as well as the presence and integrity of the DLL. The accuracy of this protocol could then be evaluated by comparing the ultrasound findings to an MRI. This future step is imperative in both the clinical translation of this study, as well as the establishment of parameters for Lisfranc injury diagnosis in ultrasound.

6.6: Conclusions

Lisfranc injuries are a rare, complicated orthopedic injury, often going misdiagnosed or overlooked for extended periods. With high rates of complications, there is a need for improved diagnostic techniques. An underutilized diagnostic tool for

Lisfranc injuries is musculoskeletal ultrasound imaging. Musculoskeletal ultrasound is an expanding area of research with advantages including reduced radiation exposure, visualization of soft tissue without expensive Magnetic Resonance imaging, and minimal pain for the patient.

This study demonstrated the ease of use and visualization of the dorsal Lisfranc ligament using ultrasound. Through gross dissection of cadaveric specimens, this study also demonstrated the consistency of the dorsal Lisfranc ligament. This ligament is easily and consistently visualized in ultrasound, although only 70-80% of its gross length is

53 represented. Length of the dorsal Lisfranc ligament was found to be independent of various anthropometric characteristics of the foot.

The interosseous Lisfranc ligament was also found to be consistent in gross dissection, and has been suggested to be the key stabilizer of the Lisfranc joint complex in previous literature. Considering the expansive depth of the interosseous Lisfranc ligament in this study, this possibility is upheld. The plantar Lisfranc ligament, while not described consistently in the literature, was found to be present in all specimens of this study, with substantial variation. A fan-shaped variant of the plantar ligament was observed in 82% of specimens, and a split variant was observed in the remaining 28% of specimens. Additionally, 64% of plantar Lisfranc ligaments had a connection to the interosseous Lisfranc ligament. The observed variability of the plantar Lisfranc ligament suggests that it may play a role in Lisfranc injuries. The presence of bony outgrowths also suggests that research regarding the prevalence of arthritis in the uninjured joint may be insightful. The gross anatomy of the Lisfranc joint complex seems to coordinate with some of the observed complications of injury to the joint.

The findings of this study support the recommended use of ultrasound to diagnose subtle Lisfranc injuries. The thinnest of the ligaments, the dorsal Lisfranc ligament, is most ruptured clinically. It is also consistent in its gross length, and can be efficiently located and visualized using ultrasonography, although its metrics in ultrasound are not accurate. Overall, musculoskeletal ultrasonography of the dorsal Lisfranc ligament remains an efficient and cost-effective diagnostic tool for Lisfranc injuries. Further research would seek to standardize the parameters of this diagnostic tool.

References

Alberta, F. G., Aronow, M. S., Barrero, M., Diaz-Doran, V., Sullivan, R. J., Adams, D. J. Ligamentous Lisfranc joint injuries: a biomechanical comparison of dorsal plate and transarticular screw fixation. Foot & Ankle International. 2005; 6:462-473. Ansede, G., Lee, J. C., Healy, J. C. Musculoskeletal sonography of the normal foot. Skeletal Radiology. 2010; 3:225-242. Bernstein, J. Musculoskeletal medicine. Rosemont, IL: American Academy of Orthopedic Surgeons; 2003. Bica, D., Armen, J., Kulas, A. S., Youngs, K., Womack, Z. Reliability and precision of stress sonography of the ulnar collateral ligament. Journal of Ultrasound in Medicine. 2015; 34:371-376.

Brunet, J., Wiley, J. The late result of tarsometatarsal joint injuries. Journal of Bone and Joint Surgery, British Volume. 1987; 3:437-440. Calder, J., Whitehouse, S., Saxby, T. Results of isolated Lisfranc injuries and the effect of compensation claims. Journal of Bone and Joint Surgery, British Volume. 2004; 4:527- 530. Castro, M., Melao, L., Canella, C., Weber, M., Negrao, P., Trudell, D., Resnick, D. Lisfranc joint ligamentous complex: MRI with anatomic correlation in cadavers. Musculoskeletal Imaging. 2010; 195:447-455. Crim, J. MR imaging evaluation of subtle Lisfranc injuries: the midfoot sprain. Magnetic Resonance Imaging Clinics of North America. 2008; 1:19-27. De Palma, L., Santucci, A., Sabetta, S. P., Rapali, S. Anatomy of the Lisfranc joint complex. Foot & Ankle International. 1997; 6:356-364. Delfaut, E. M., Rosenberg, Z. S., Demondion, X. Malalignment at the Lisfranc joint: MR features in asymptomatic patients and cadaveric specimens. Skeletal Radiology. 2002; 9:499-504. DeOrio, M., Erickson, M., Usuelli, F. G., Easley, M. Lisfranc injuries in sport. Foot and Ankle Clinics of North America. 2009; 2:169-186.

DiDomenico, L. A., Cross, D. Tarsometatarsal/Lisfranc joint. Clinics in Podiatric Medicine and Surgery. 2012; 2:222-242. Englanoff G., Anglin, D., Hutson, H. Lisfranc fracture-dislocation: a frequently missed diagnoses in the emergency department. Annals of Emergency Medicine. 1995; 2:229- 233. Gallagher, S. M., Rodriguez, N. A., Andersen, C. R., Granberry, W. M., Panchbhavi, V. K. Anatomic predisposition to ligamentous Lisfranc injury: a matched case-control study. The Journal of Bone and Joint Surgery, American Volume. 2013; 22:2043-2047. Graves, N. C., Rettedal, D. D., Marshall, J. J., Frush, K., Vardaxis, V. Ultrasound assessment of dorsal Lisfranc ligament strain under clinically relevant loads. Journal of the American Podiatric Medical Association. 2014; 2:11-19. Gupta R. T., Wadhwa R. P., Learch, T. J., Herwick, S. M. Lisfranc injury: imaging findings for this important but often-missed diagnosis. Current Problems in Diagnostic Radiology. 2008; 3:115-126. Hardcastle, P. H., Reschauer, R., Kutscha-Lissberg, E., Schoffmann, W. Injuries to the tarsometatarsal joint. Journal of Bone and Joint Surgery, British Volume. 1982; 3:349- 356.

Hatem, S. Imaging of Lisfranc injury and midfoot sprain. Radiologic Clinics of North America. 2008; 6:1045-1060. Hirano T., Niki, H., Beppu, M. Anatomical considerations for reconstruction of the Lisfranc ligament. Journal of Orthopedic Science. 2013; 5:720-726. Ibrahim, N., Ryba, D., Jaramillo, T., Choi, J., Vardaxis, V. Relationship between ultrasound imaging of the Lisfranc ligament length and clinical biomechanical measurement changes with load. The Foot. 2014; 4:218. Johnson, A., Hill, K., Ward, J., Ficke, J. Anatomy of the Lisfranc ligament. Foot and Ankle Specialist. 2008; 1:19-23. Kaar, S. Lisfranc joint displacement following sequential ligament sectioning. The Journal of Bone and Joint Surgery (American Volume). 2007; 10:2225-2232. Kadel, N., Boenisch, M., Teitz, C., Trepman, E. Stability of Lisfranc joints in ballet pointe position. Foot & Ankle International. 2005; 5:394-400. Kaicker, J., Zajac, M., Shergill, R., Choudur, H. N. Ultrasound appearance of the normal Lisfranc ligament. Emergency Radiology. 2016; 6:609-614.

Kichouch, M., Vanhoenacker, F., Jager, T., van Roy, P., Pouders, C., Marcelis, S., van Hedant, E., De Mey, J. Functional anatomy of the dorsal hood of the hand: correlation of ultrasound and MR findings with cadaveric dissection. European Radiology. 2009; 8:1849-1856. Kitsukawa, K., Hirano, T., Niki, H., Tachizawa, N., Nakajima, Y., Hirata, K. MR imaging evaluation of the Lisfranc ligament in cadaveric feet and patients with acute to chronic Lisfranc injury. Foot & Ankle International. 2015; 12:1483-1492. Kuo, R., Tejwani, N., DiGiovanni, C., Holt, S., Benirschke, S., Hansen, S., Sangeorzan, B. Outcome after open reduction and internal fixation of Lisfranc joint injuries. Journal of Bone and Joint Surgery. 2000; 11:1609-1618. Kura, H. Luo, Z.-P. Kitaoka, H. B., Smutz, W. P., An, K.-N. Mechanical behavior of the Lisfranc and dorsal cuneometatarsal ligaments: in vitro biomechanical study. Journal of Orthopaedic Trauma. 2001; 2:107-110. Lee, C. A., Birkedal, J. P., Dickerson, E. A., Vieta, P. A., Webb, L. X. Teasdall, R. D. Stabilization of Lisfranc joint injuries: a biomechanical study. Foot & Ankle International. 2004; 5:365-370. Lento, P. H., Primack, S. Advances and utility of diagnostic ultrasound in musculoskeletal medicine. Current Reviews in Musculoskeletal Medicine. 2008; 1:24-31. Lewis, J. S., Anderson, R. B. Lisfranc injuries in the athlete. Foot and Ankle International. 2016; 12:1374-1380.

Lu, J. Ebraheim, N. A., Skie, M., Porshinksy, B., Yeasting, R. A. Radiographic and computer tomographic evaluation of Lisfranc dislocation: a cadaver study. Foot & Ankle International. 1997; 6:351-355. Marshall, J. J., Graves, N. C., Rettedal, D. D., Frush, K., Vardaxis, V. Ultrasound assessment of bilateral symmetry in dorsal Lisfranc ligament. The Journal of Foot and Ankle Surgery. 2013; 3:319-323. Meyer S. A., Callaghan, J. J, Albright, J. P., Crowley, E. T., Powell, J. W. Sprains in collegiate football players. The American Journal of Sports Medicine. 1994; 3:392-401. McHale, K. J., Rozell, J. C., Milby, A. H., Carey, J. L., Sennett, B. J. Outcomes of Lisfranc Injuries in the National Football League. American Journal of Sports Medicine. 2016; 44:1810-1817. Myerson M. S., Cerrato, R. A. Current management of tarsometatarsal injuries in the athlete. The Journal of Bone and Joint Surgery (American Volume). 2009; 11: 2521-2533

Panchbhavi, D. D., Molina, D. Villarreal, J., Curry, M. C., Andersen, C. R. Three- dimensional, digital, and gross anatomy of the Lisfranc ligament. Foot & Ankle International. 2013; 6:876-880. Panchbhavi, V. K., Anderson, C. R., Vallurupalli, S., Yang, J. A minimally disruptive model and three-dimensional evaluation of Lisfranc joint diastasis. The Journal of Bone and Joint Surgery, American Volume. 2008; 12:2707-2713. Peicha, G., Labovitz, J., Seibert, F. J., Grechenig, W., Weiglein, A., Preidler, K. W., Quehenberger, F. The anatomy of the joint as a risk factor for Lisfranc dislocation and fracture-dislocation: an anatomical and radiological case control study. The Journal of Bone and Joint Surgery, British Volume. 2002; 7:981-985. Philbin T. Rosenberg, G., Sferra J. Complications of missed or untreated Lisfranc injuries. Foot and Ankle Clinics. 2003; 1: 61-71 Rettedal, D. D., Graves, N. C., Marshall, J. J., Frush, K., Vardaxis, V. Reliability of ultrasound imaging in the assessment of the dorsal Lisfranc ligament. Journal of Foot and Ankle Research. 2013; 1:7. Richter, M. Thermann, H., Huefner, T., Schmidt, U., Krettek, C. Aetiology, treatment, and outcome in Lisfranc joint dislocations and fracture dislocations. Foot and Ankle Surgery. 2002; 1:21-32. Ryba, D., Ibrahim, N., Choi, J., Vardaxis, V. Evaluation of dorsal Lisfranc ligament deformation with load using ultrasound imaging. The Foot. 2016; 1:30-35. Shereif, T. Mucci, B., Greiss, M. Lisfranc injury: how frequently does it get missed? And how can we improve? Injury. 2007; 7: 856-860. Solan, M. C., Moorman, C. T., Miyamoto, R. G., Jasper, L. E., Belkoff, S. M. Ligamentous restraints of the second tarsometatarsal joint: a biomechanical evaluation. Foot & Ankle International. 2001; 8:637-641. Welck, M. J., Zinchenko, R., Rudge, B. Lisfranc injuries. Injury. 2015; 46:536-541.

Woodward, S., Jacobson, J.A. Femino, J. E., Morag, Y., Fesseell, D. P., Dong, Q. Sonographic evaluation of Lisfranc ligament injuries. Journal of Ultrasound in Medicine. 2009; 28:351-357

Yu-Kai, Y., Shui-Bii, L. Anatomic parameters of the Lisfranc joint complex in a radiographic and cadaveric comparison. Journal of Foot and Ankle Surgery. 2015; 5:883- 887.

Appendix A: Data Tables

Table 12. Cadaver information, including sex, age, and anthropometric measurements of the foot

Calcaneus - Distal Calcaneus - M1 Calcaneus - M5 M1 - M5 C1/M2 Mortise ID Sex Age M2 Length Phalanx Head Head Width Medial Depth LF01 F 97 234 178 170 78 81 10.76 LF02 M 92 275 200 186 92 90 9.52 LF03 M 62 255 195 172 98 84 10.17 LF06 M 94 272 208 189 90 88 10.86 LF08 F 99 235 180 164 87 85 - LF09 M 67 255 196 179 105 85 11.28 LF10 F 91 247 184 171 98 85 12.21 LF11 M 78 264 192 176 103 86 10.8 LF12 M 60 251 198 184 94 79 10.14 LF14 M 56 261 199 177 103 84 10.48 LF15 M 74 266 209 184 93 91 12.21 LF16 M 91 258 195 177 85 83 9.76 LF17 M 72 262 200 186 99 86 10.82 LF18 F 87 235 179 165 90 83 9.47 LF19 F 86 228 177 164 92 78 10.81 LF20 F 79 218 170 158 87 77 7.82 LF21 M 65 269 205 183 108 91 11.18 LF22 F 96 242 187 167 92 83 10.63

Average 80.3333 251.5 191.7777778 175.1111111 94.11111111 84.388889 10.52470588

SD 14.0796 16.35722542 11.54813739 9.183674062 7.72991811 4.0604098 1.042875338

Table 13. Measurement of DLL using Sonosite M-Turbo, ImageJ, and gross dissection

Sonosite M-Turbo ImageJ Dissection

Dorsal Joint Dorsal Joint Dorsal Joint ID Length Length Thickness Length Thickness Width Space Space Space LF01 7.6 2.3 5.6546 1.6311 - 10.38 1 0.84 8.52 LF02 8.2 2.2 8.3526 1.8824 4.299 9.23 1.43 1.3 7.09 LF03 8.2 2.5 6.1896 1.9147 5.069 10.78 0.81 1.24 8.7 LF06 10.2 2.6 10.0679 2.3528 5.069 10.77 0.86 2.02 9.65 LF08 8.9 1.5 7.5189 1.2979 3.761 11.59 - - 8.87 LF09 7.6 1.7 9.3173 2.1644 4.332 11.88 0.89 1.02 8.17 LF10 7.8 1.3 5.8942 1.6715 4.836 11.73 0.74 1.5 8.56 LF11 6 2.1 10.8543 2.6328 - 13.41 0.99 1.26 8.52 LF12 9.4 2.5 9.9838 2.8151 - 9.99 0.98 1.29 8.79 LF14 11.2 2.8 12.0994 2.3398 1.612 13.15 0.83 1.96 7.54 LF15 7 2.7 8.0761 2.3423 6.559 11.99 1.32 1.98 6.22 LF16 9.7 2.9 10.0849 2.4305 5.4 14.62 1.45 1.53 9.64 LF17 6.7 1.6 7.073 1.4012 2.149 9.57 0.82 1.82 10.45 LF18 8.8 2.1 6.5085 1.331 4.197 10.47 1.04 0.75 8.35 LF19 8.9 2.1 8.598 2.4353 - 8.57 0.88 0.83 9.5 LF20 8.9 2.5 6.4781 1.7321 5.373 9.33 0.89 0.85 6.62 LF21 8 1.5 7.4414 1.5432 - 7 1.29 1.27 4.33 LF22 8 2.6 8.2736 2.9894 - 9.97 1.43 1.62 9.84

Average 8.39444 2.194444444 8.24812 2.050416667 4.388 10.8017 1.038235294 1.357647 8.29778 SD 1.26792 0.492857481 1.84481 0.520267848 1.38156 1.84999 0.244852897 0.421879 1.49336

Table 14. Measurement of the ILL in dissection. Due to connections to the PLL and bony outgrowths in some specimens, not all measurements could be obtained

ID Length Width Thickness LF01 - - - LF02 10.2 0.06 16.44 LF03 10.87 2.09 14.81 LF06 9.9 - 11.51 LF08 - - - LF09 9.92 - 14.88 LF10 12.01 - 11.34 LF11 10.12 1.95 14.13 LF12 12.81 - 13.52 LF14 9.54 3.03 19.23 LF15 11.8 - 15.52 LF16 9.3 - 16.45 LF17 - - - LF18 8.83 - 10.57 LF19 10.68 0.45 9.66 LF20 7.24 1.46 8.1 LF21 4.13 2.55 17.22 LF22 8.17 - 12.69

Average 9.701333333 1.65571429 13.738 SD 2.114949735 1.08027554 3.082650066

Table 15. Measurement of the PLL fan variant in gross dissection. Specimens possessing the fan variant had a narrow origin on C1 that spread to have a wide insertion across the plantar aspects of the M2 and M3 bases

Length Width Thickness

ID ILL Connection C1 - M2 C1 - M3 Proximal Distal Proximal LF01 No 16.9 14.73 2.96 8.56 1.05 LF02 Yes 11.91 13.11 3.08 7.56 2.54 LF03 No 9.6 10.61 5.29 8.69 1.78 LF06 Yes 15.42 11.17 4.34 11.23 2.16 LF09 No 10.81 12.39 9.06 11.95 3.51 LF10 Yes - - - - - LF11 No 11.1 8.77 6.15 9.96 2.72 LF14 No 18.16 16.13 5.84 - 1.95 LF15 Yes 12.94 14.9 8.04 9.21 2.58 LF17 Yes 14.66 11.69 5.2 10.76 1.38 LF18 Yes 12.92 11.69 6.42 5.38 1.02 LF19 Yes 14.52 13.94 6.4 7.05 2.34 LF21 Yes 12.18 13.37 8.62 - 1.6 LF22 Yes 11.41 12.86 5.12 6.78 1.78

Average 13.27153846 12.72 5.886153846 8.83 2.031538462

SD 2.519328105 1.983074213 1.894019265 2.040083332 0.710713798

Table 16. Measurement of the PLL split variant in dissection. Specimens in this category demonstrated separate insertions on M2 and M3. Two specimens – LF12 and LF20 – had a common origin on C1 before bifurcating to insert on M2 and M3. LF16 demonstrated 2 bands that began separately on C1 before inserting on M2 and M3

Length Width Thickness

ILL C1 - C1 - C1 - Bifurcation Bifurcation - C1 - M2 M3 C1 - M2 M3 ID Connection M2 M3 Bifurcation - M2 M3 Bifurcation Insertion Insertion Bifurcation Insertion Insertion LF12 Y 12.23 13.78 9.15 5.81 5.17 5.8 3.02 6.46 1.58 0.59 1.06 LF16 Y 12.47 12.47 - - - - 4.77 1.77 - 2.86 1.25 LF20 N 17.55 15.22 11.61 5.63 7.09 4.48 3.81 5.55 1.11 0.91 0.62

Average 14.083 13.82 10.38 5.72 6.13 5.14 3.866667 4.593333 1.345 1.453333 0.97667

SD 3.0046 1.376 1.739483 0.12728 1.35765 0.93338 0.876375 2.487053 0.3323402 1.228671 0.32316

Appendix B: Ultrasound Scan Protocol

1. Check machine set up 2. Position cadaver – supine 3. Palpate the first and second tarsometatarsal joints and the first and second cuneonavicular joints a. MARK each joint line with a pen 4. Apply gel to the dorsum of the foot 5. Place probe cross-sectionally on the dorsum of the first and second metatarsals, with the leading edge facing midline 6. Identify the shafts of M1 and M2 7. Move probe proximally toward the tarsometatarsal joints 8. Leading edge will should be on C1, trailing edge on M2 base 9. Adjust probe relative to the joint markings on the skin 10. Adjust probe to find best image a. FREEZE 11. Label video a. “Comment” button, Type “ID, DLL, Side” (ex: LF01 DLL, LEFT) b. Use scroll and “Select” button to lock comment in bottom left corner 12. Save best 2-3 images a. P1 button – will make a “ding” noise

Appendix C: Dissection Protocol

1. Remove all tendons, musculature, and neurovasculature from the dorsum of the foot a. Cut the tendons distally and reflect them superiorly i. Extensor hallucis longus m., extensor digitorum longus m., tibialis anterior m., extensor hallucis brevis m., extensor digitorum brevis m. 2. Remove all tendons that attach to the 1st – 3rd digits on the plantar surface a. Flexor hallucis longus m., flexor digitorum brevis m., abductor hallucis m., flexor digitorum longus m. (with quadratus plantae), flexor hallucis brevis m. 3. On the plantar surface, cut the tunnel of the long plantar ligament to expose fibularis longus tendon a. Cut fibularis longus tendon from distal attachment and retract b. At this point, there should not be any tendon attaching to the 1st-3rd metatarsals or phalanges, nor to the three cuneiforms 4. Cut the intermetatarsal ligaments, muscles, and fascia between third and fourth metatarsals 5. Palpate the navicular tuberosity and palpate distally to find the first cuneonavicular joint a. Stretching the joint capsule may help here – use one hand to stabilize the ankle and hindfoot and use one hand to abduct the entire forefoot gently b. Use a scalpel to cut the joint capsule to open the first cuneonavicular joint c. Use scissors to continue to cut the joint capsule surrounding the three cuneonavicular joints d. Remove the bloc from the rest of the foot i. Should contain the three cuneiforms, first – third metatarsals and associated phalanges (Figure 1). 6. Remove the lateral and intermediate cuneiforms, and the first metatarsal and its phalanges a. All that should remain are the medial cuneiform, second metatarsal, third metatarsal, and Lisfranc ligaments 7. Measure second metatarsal length a. from 2nd tarsometatarsal joint to second metatarsal head (better after isolation?) b. measure mortise depth (of M2 in pocket between C1 and C3) 8. Measure Lisfranc ligaments a. Dorsal – length, width, thickness (depth), joint space (if possible) 66 b. Interosseous – length, width, thickness (depth) c. Plantar – length, width, thickness (depth) i. From medial cuneiform to second metatarsal – Length ONLY ii. From medial cuneiform to third metatarsal – Length ONLY iii. From medial cuneiform to split iv. From split to second metatarsal v. From split to third metatarsal