Imaging of Chopart (Midtarsal) Joint Complex: Normal Anatomy and Posttraumatic Findings

Revisiting the inferior supports of Chopart joint complex

Aims

The Chopart joint complex is a joint between the midfoot and hindfoot. The static and dynamic support system of the joint is critical for maintaining the medial longitudinal arch of the foot. Any dysfunction leads to progressive collapsing flatfoot deformity (PCFD). Often, the tibialis posterior is the primary cause; however, contrary views have also been expressed. The present investigation intends to explore the comprehensive anatomy of the support system of the Chopart joint complex to gain insight into the cause of PCFD.

Methods

The study was conducted on 40 adult embalmed cadaveric lower limbs. Chopart joint complexes were dissected, and the structures supporting the joint inferiorly were observed and noted.

Results

The articulating bones exhibit features like a cuboid shelf and navicular beak, which appear to offer inferior support to the joint. The expanse of the spring ligament complex is more medial than inferior, while the superomedial part is more extensive than the intermediate and inferoplantar parts. The spring ligament is reinforced by the tendons in the superomedial part (the main tendon of tibialis posterior), the inferomedial part (the plantar slip of tibialis posterior), and the master knot of Henry positioned just inferior to the gap between the inferomedial and inferoplantar bundles.

Conclusion

This study highlights that the medial aspect of the talonavicular articulation has more extensive reinforcement in the form of superomedial part of spring ligament and tibialis posterior tendon. The findings are expected to prompt further research in weightbearing settings on the pathogenesis of flatfoot.

Factors influencing functional outcome of fractures of the anterior process of the calcaneus

INTRODUCTION

Fractures of the anterior process of the calcaneus (APC) are easily overlooked in clinical practice. Most patients have good to excellent clinical outcome after conservative treatment, while some patients may have persisting symptoms and unfavorable functional outcomes. The aim of this study was to identify the risk factors associated with unfavorable functional outcome after conservative treatment in APC fractures.

METHODS

All patients presenting with APC fractures and receiving conservative treatment from April 2019 to April 2020 were retrospectively assessed. The primary outcome measurement was the ankle joint function assessed using Karlsson Scoring System at 2 years post-injury. The risk factors associated with unfavorable functional outcomes (Karlsson score ≤ 80) were evaluated by logistic regression analysis.

RESULTS

In total, 84 patients were included with a mean age of 40 years. 26 (31%) patients presented with unfavorable functional outcome at 2 years post-injury. In multivariate logistic regression, concomitant fractures of talonavicular (TN) joints and older age were significantly associated with unfavorable functional outcome (p<0.05). Patients with concomitant fractures of TN joints had an odds ratio of 3.623 for unfavorable functional outcome. The optimal cutoff age for an unfavorable outcome was ≥ 47.5 years, with an odds ratio of 5.010.

CONCLUSION

Most patients with APC fractures achieved good to excellent results when treated conservatively. Attention should be paid to those with concomitant fractures of TN joints and with age ≥ 47.5 years, which might lead to unfavorable functional recovery.

LEVEL OF EVIDENCE

IV; case series.

Chopart dislocations: a review of diagnosis, treatment and outcomes

INTRODUCTION

Chopart injuries can be allocated into 4 broad groups, ligamentous injury with or without dislocation and fracture with or without dislocation, which must occur at the talonavicular joint (TNJ) and/or calcaneocuboid joint (CCJ). Chopart dislocations are comprised of pure-dislocations and fracture-dislocations. We aim to review the literature, to enable evidence-based recommendations.

METHODS

A literature search was conducted to identify relevant articles from the electronic databases, PubMed, Medline and Scopus. The PRISMA flow chart was used to scrutinise the search results. Articles were screened by title, abstract and full text to confirm relevance.

RESULTS

We identified 58 papers for analysis, 36 case reports, 4 cohort studies, 4 case series and 14 other articles related to the epidemiology, diagnosis, treatment and outcomes of Chopart dislocations. Diagnostic recommendations included routine imaging to contain computed tomography (CT) and routine examination for compartment syndrome. Treatment recommendations included early anatomical reduction, with restoration and maintenance of column length and joint congruency. For both pure-dislocations and fracture-dislocations urgent open reduction and internal fixation (ORIF) provided the most favourable long-term outcomes.

CONCLUSIONS

Chopart dislocations are a complex heterogenous midfoot injury with historically poor outcomes. There is a relative paucity of research discussing these injuries. We have offered evidence-based recommendations related to the clinical and surgical management of these rare pathologies.

Imaging of osteoarthritis from the ankle through the midfoot

Ankle, hindfoot, and midfoot osteoarthritis (OA) is most commonly posttraumatic and tends to become symptomatic in younger patients. It often results from instability due to insufficiency of supportive soft tissue structures, such as ligaments and tendons. Diagnostic imaging can be helpful to detect and characterize the distribution of OA, and to assess the integrity of these supportive structures, which helps determine prognosis and guide treatment. However, the imaging findings associated with OA and instability may be subtle and unrecognized until the process is advanced, which may ultimately limit therapeutic options to salvage procedures. It is important to understand the abilities and limitations of various imaging modalities used to assess ankle, hindfoot, and midfoot OA, and to be familiar with the imaging findings of OA and instability patterns.

Don't Miss Me: Midfoot Sprains, A Point-of-Care Review

Athletes practicing high-contact sports are exposed to an increased risk of midfoot injuries, namely midtarsal sprains. The complexity of reaching an accurate diagnosis is clearly depicted in the reported incidence of midtarsal sprains, ranging from 5% to 33% of ankle inversion injuries. Because the focus of the treating physician and physical therapist is on lateral stabilizing structures, midtarsal sprains are missed at initial evaluation in up to 41% of patients, with delayed treatment as a result.Detecting acute midtarsal sprains requires a high degree of clinical awareness. Radiologists must become familiar with the characteristic imaging findings of normal and pathologic midfoot anatomy to avoid adverse outcomes such as pain and instability. In this article we describe Chopart joint anatomy, mechanisms of midtarsal sprains, clinical importance, and key imaging findings with a focus on magnetic resonance imaging. A team effort is essential to provide optimal care for the injured athlete.

MRI in Acute Ankle Sprains: Should We Be More Aggressive with Indications?

Acute ankle sprains are common sports injuries. MRI is the most accurate test for assessing the integrity and severity of ligament injuries in acute ankle sprains. However, MRI may not detect syndesmotic and hindfoot instability, and many ankle sprains are treated conservatively, questioning the value of MRI. In our practice, MRI adds value in confirming the absence or presence of ankle sprain-associated hindfoot and midfoot injuries, especially when clinical examinations are challenging, radiographs are inconclusive, and subtle instability is suspected. This article reviews and illustrates the MRI appearances of the spectrum of ankle sprains and associated hindfoot and midfoot injuries.

L’entorse du médiopied (de Chopart)

L’entorse de Chopart est une lésion traumatique peu connue, sous-estimée et souvent confondue avec une entorse de cheville. Le traumatisme en inversion de la cheville, souvent accompagné d’une flexion plantaire forcée du pied, représente le mécanisme lésionnel le plus fréquent. Son diagnostic repose sur un examen clinique précis nécessitant une bonne connaissance anatomique. Les signes radiographiques sont indirects et souvent discrets. Il s’agit principalement d’arrachements osseux ou de lésions osseuses par impaction ; ils peuvent parfois d’emblée justifier d’un complément scanographique. L’échographie peut également être utile en première intention. A contrario, l’IRM est actuellement réservée aux difficultés diagnostiques. Le traitement de cette pathologie est essentiellement fonctionnel. Il faut cependant connaître les quelques indications pour un traitement orthopédique (immobilisation) comme la présence d’une lésion osseuse de grande taille. Le traitement chirurgical est quant à lui exceptionnel. L’instabilité calcanéocuboïdienne ainsi que l’arthrose du Chopart sont des complications possibles (à moyen ou long terme) mais peu fréquentes.

Magnetic resonance imaging of midtarsal sprain: Prevalence and impact on the time of return to play in professional soccer players

BACKGROUND

Ankle sprain is a common injury in professional soccer, but to date midtarsal sprain has not been investigated in this context. The purpose of this study was to determine the prevalence of midtarsal sprain by MRI and to assess its impact on the time of return to play in professional soccer players.

METHODS

We included 52 professional soccer players who underwent 59 MRI examinations after acute ankle trauma between January 2012 and September 2019. Images were retrospectively reviewed in consensus by two radiologists for assessment of midtarsal sprain and ankle sprain. Ligaments were graded as i) normal, ii) partial tear, or iii) complete tear. Time to return to play (RTP) for each athlete was retrieved from team medical records. A Kruskal-Wallis test and Dunn's pairwise tests were used to calculate differences in RTP time between groups with i) isolated midtarsal sprain, ii) isolated lateral ankle sprain, and iii) combined midtarsal and lateral ankle sprain.

RESULTS

MRI revealed isolated ankle sprain in 24 of 59 MRI examinations (40.6 %). Acute midtarsal ligament injury was present in 15 examinations (25.4 %). Four of the 15 examinations (26.7 %) had isolated midtarsal injuries and eleven of the 15 examinations (73.3 %) had concomitant ankle sprain. RTP time was 39 days (range 9-70 days) for isolated midtarsal sprain. RTP time was significantly higher for athletes with combined ankle and midtarsal sprain (47 days, range 15-74 days) when compared to athletes with isolated ankle sprain (24 days, range 2-59 days) (p = .019).

CONCLUSION

Our MRI study reveals that midtarsal sprain is a frequent injury in professional soccer players with ankle sprain. Midtarsal ligament findings on MRI combined with evidence of lateral ankle sprain is associated with a longer time of return to play compared to isolated lateral ligament injuries.

LEVEL OF EVIDENCE

Retrospective study, observational study.

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSIONS

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

Advanced Ankle and Foot Sonoanatomy: Imaging Beyond the Basics

Ankle/foot pain is a common complaint encountered in clinical practice. Currently, due to the complex anatomy, the diagnosis and management of the underlying musculoskeletal disorders are extremely challenging. Nowadays, high-resolution ultrasound has emerged as the first-line tool to evaluate musculoskeletal disorders. There have been several existing protocols describing the fundamental sonoanatomy of ankle/foot joints. However, there are certain anatomic structures (e.g., Lisfranc ligament complex or Baxter nerve) which are also clinically important. As they are rarely elaborated in the available literature, a comprehensive review is necessary. In this regard, the present article aims to brief the regional anatomy, illustrate the scanning techniques, and emphasize the clinical relevance of the ankle/foot region.

Biomechanical Considerations in Rearfoot Fusions

This article discusses rearfoot fusions for foot and ankle surgeons. It establishes normal foot and ankle function primarily in the stance phase of gait. The foot is greatly affected by external and internal forces, which contribute to normal function or the need for compensatory mechanisms. As a result of compensation, many symptoms develop, often leading to debilitating disorders such as degenerative joint disease. The interaction of the ankle, subtalar, and midtarsal joints are outlined. Congenital deformities, trauma and abnormal compensation are reviewed along with corresponding sequelae. Surgery is often indicated to reduce symptoms, improve position, and help stabilize the foot.

Anatomico-radiological Study of the Bifurcate Ligament of the Foot with Clinical Significance

Introduction

Lateral ankle sprain caused by forcible plantar flexion and inversion of the foot commonly damages the anterior talofibular ligament and other ligaments. Unfortunately, involvement of the bifurcate ligament (BL) is often overlooked when assessing such injuries in clinical practice and identification of this ligament on magnetic resonance (MR) scans can be challenging. Anatomically, the BL is a Y-shaped structure with two bands: the calcaneonavicular ligament (CNL) and calcaneocuboid ligament (CCL). There are few anatomical studies on the morphometric characteristics of the BL and even fewer biomechanical studies. Therefore, the objective of this anatomico-radiological study was to investigate the morphology of the BL using a multifaceted approach, and classify the fiber characteristics of the CNL and CCL.

Materials and methods

We measured the length and the width of 53 embalmed cadaveric feet. Meticulous dissection of each foot was performed to expose the BL. Measurements of the length, width, thickness, and shape of the CNL and CCL were taken using a digital caliper. We also documented the fiber orientation of each ligament, and used a goniometer to measure the bifurcation angle between the CNL and CCL via two methods. Confirmatory histologic analysis of the ligaments was performed and digital radiographs of the ligaments with attached radiopaque monofilament were taken. We also included an MR scan of the BL. Using descriptive and inferential statistics, we documented any significant relationships between the variables.

Results 

Mean (range) age at death of cadavers was 76 (42-94) years. The CNL was found in all the feet and the CCL was not present in 9.4% of the feet. Mean (standard deviation) length of the CNL and CCL was 22.7 (4.12) mm and 10.9 (2.53) mm, respectively. Mean (standard deviation) thickness of the CNL and CCL was 3.23 (1.56) mm and 1.48 (0.71) mm, respectively. Related to ligament morphology, the CNL was most frequently cord shaped (67.92%) and the CCL was most frequently flat shaped (83.33%). The mean bifurcation angle measured 32.75^o and 29.31^o in methods 1 and 2, respectively. The correlation between the two measured angles was very strong (p < 0.001).

Discussion

We found that 90.6% of feet had both the CNL and CCL, 9.4% had the CNL and no CCL, and none (0%) had the CCL and no CNL. These frequencies are similar to a recent Japanese study. Our sample of donors were American and predominantly white. Whether the difference in frequencies between the studies is related to ethnicity is unknown and requires future investigation. Interestingly, on average the CNLs were twice as long and twice as thick as the CCLs. The CCLs tended to be wider distally and tapered compared to the CNLs.

Conclusions

Our findings better classify the morphology and fiber orientation of the BL. Coupled with the radiographs and MR scan, our data may be of particular value to radiologists and surgeons. Our BL fiber orientation classification system and angle measurements can pave the way for future biomechanical studies to investigate any relationships between fiber type, angle, and strength of the constituent bands. More accurate descriptions of the BL should lead to improved diagnosis and treatment of ligamentous injuries of the foot.

Normal Anatomy and Traumatic Injury of the Midtarsal (Chopart) Joint Complex: An Imaging Primer

The midtarsal (Chopart) joint complex consists of the talonavicular and calcaneocuboid joints and their stabilizing ligaments. Detailed assessment of this complex at MRI can be challenging owing to frequent anatomic variation and the small size of the structures involved. Nevertheless, a wide spectrum of pathologic conditions affect the joint complex, and its imaging evaluation deserves more thorough consideration. This review focuses on MRI evaluation of normal ligamentous anatomy and common variations about the Chopart joint, presenting practical imaging tips and potential diagnostic pitfalls. Imaging findings across a spectrum of traumatic Chopart joint injuries are also reviewed, from midtarsal sprains to Chopart fracture-dislocations. Midtarsal sprains-commonly associated with ankle inversion injuries-are emphasized, along with their often predictable radiographic and MRI injury patterns. Online DICOM image stacks are available for this article. ^©RSNA, 2018.