Marie-Lyne Nault

CT scan assessment of the syndesmosis: a new reproducible method.

Objectives: Anatomic reduction of the fibula with regard to the tibia is the goal when treating syndesmotic injuries. No objective method exists to describe the distal tibiofibular relationship. The primary and secondary objectives of this study was to describe and validate radiologic measurements of the syndesmosis and to establish a set of normal values, respectively. Methods: A set of 6 measurements and 2 angles were defined on axial computed tomography scans. These measures describe distal tibiofibular anatomy in rotation, lateral translation, and anteroposterior position. A series of 100 ankle computed tomography scans were measured by 2 evaluators. Interobserver reliability was assessed on a subset of 30 scans by 3 different evaluators. Measurements were repeated 6 weeks later by 2 evaluators for intraobserver reliability. All correlations were evaluated with intraclass correlation coefficients. Results: Good correlations for nearly all measurements were found, with intraclass correlation coefficients over 0.5. The lateral translation was the most reliable measure with a mean value of 2.8 mm. The mean ratio of anterior tibiofibular distance to posterior tibiofibular distance was 0.54. Proximal to tibial plafond, the fibula is internally rotated 8.7 degrees and at the talar dome level it is in 6.9 degrees of external rotation. Conclusions: Several studies have shown that the reduction of the syndesmosis is essential to restore normal ankle mechanics and prevent secondary degenerative changes. The evaluation criteria developed in this study can give the surgeon a guideline for evaluating syndesmosis anatomy with reliable parameters. Concerning the normal range of motion, our radiologic measurements of 100 normal ankles showed that a significant amount of variability exists in the uninjured distal tibiofibular relationship.

Three-Dimensional Spinal Morphology Can Differentiate Between Progressive and Nonprogressive Patients With Adolescent Idiopathic Scoliosis at the Initial Presentation: A Prospective Study

Study Design. This is a prospective case-control study. Objective. The objective of this study was to compare 3-dimensional (3D) morphological parameters of the spine at the first visit between a nonprogressive (NP) and a progressive (P) group of immature adolescent idiopathic scoliosis (AIS). Summary of Background Data. Prediction of curve progression remains challenging in AIS at the first visit. Prediction of progression is based on curve type, curve magnitude, and skeletal or chronological age. Methods. A prospective cohort of 133 AIS was followed from skeletal immaturity to maturity (mean, 37 mo). The first group was made up of patients with AIS with a minimum 6-degree progression of the major curve between the first and last follow-up (P) (n = 53) and the second group was composed of patients with NP who reached maturity with less than 6-degree progression (n = 81). Computerized measurements were taken on reconstructed 3-dimensional (3D) spine radiographs of the first visit. There were 6 categories of measurements: angle of plane of maximum curvature, Cobb angles (kyphosis, lordosis), 3D wedging (apical vertebra, apical disks), rotation (upper and lower junctional vertebra, apical vertebra, and thoracolumbar junction), torsion, and slenderness (height/width ratio). t tests were also conducted. Results. There was no statistical difference between the 2 groups for age and initial Cobb angle. P presented significant hypokyphosis, and parameters related to rotation presented significant statistical differences between NP and P (plane of maximal curvature, torsion, and apical axial rotation). Depth slenderness also presented statistical differences. Conclusion. This study confirms that even at the initial visit, 3D morphological differences exist between P and NP AIS. It supports the use of 3D reconstructions of the spine in the initial evaluation of AIS to help predict outcome. Level of Evidence: 3

Three-dimensional spine parameters can differentiate between progressive and nonprogressive patients with AIS at the initial visit: a retrospective analysis.

Background: Knowledge concerning morphology of the spine is reported in 2-dimensional (2D) or focuses on modification of parameters with progression of spinal deformation. The objective of this study was to compare 3-dimensional (3D) morphologic parameters of the spine at the first visit between progressive and a nonprogressive group of immature adolescent idiopathic scoliosis (AIS). Methods: The first group was made up of surgically corrected AIS patients (E) (n=19), whereas the second group was composed of nonprogressive AIS that had reached skeletal maturity (n=18). Computerized measurements were undertaken on reconstructed 3D spines. There were 5 categories of measurement: Cobb angles (scoliosis, kyphosis, lordosis), 3D wedging (apical vertebra, mean 2 apical disks), rotation (upper and lower junctional vertebra, apical vertebra, and disk), torsion, and slenderness (height/width ratio of T6, L4, and T1-L5). Nonparametric Mann-Whitney tests were also undertaken. Results: There was no statistical difference between the 2 groups for age, 3D Cobb angle, lordosis, and kyphosis. Mean 3D wedging of the apical disks, lower junctional vertebral axial rotation, torsion and T6, and whole spine height/width ratio were all significantly affected. Conclusions: This study supports the theory that wedging begins in the disks and then in the vertebral body and identifies 3D morphologic parameters that could be used in the prediction of AIS evolution. The findings in the junctional area illustrate that a torsional deformity seems to occur distally from the apex and creates a progressive scoliosis. Curve progression could be predicted based on 3D morphometric parameters, as early as the initial visit. Level of Evidence: Level III—this is a case-control retrospective study.

Variation of Syndesmosis Anatomy With Growth.

Background: Syndesmosis injury is common in trauma and in the sport medicine population. Diagnosis and treatment of this pathology is controversial in adult population and almost unknown in a growing and immature ankle. The objective of this study was to describe the relationship between the distal tibia and fibula in immature, growing, and mature children. Methods: A retrospective imaging study was performed on ankle magnetic resonance images (MRI), which were divided into 3 groups according to age: immature, growing, or mature. The syndesmosis anatomy was described in 3 planes following an established measurement system. The measurement system was also validated (intraobserver and interobserver reproducibility) on a subgroup of 30 MRIs with 4 surgeons. Results: The measurement system, previously described on CT scans, is valid when used on MRIs. The mediolateral translation significantly increases with growth and external rotation of fibula decreases. The anteroposterior position is also significantly different between groups but the ratios are similar. Conclusions: This study reported differences in distal tibiofibular relationship in a growing population. This information will be crucial in future development of diagnostic and follow-up criteria of syndesmosis injury. It also presented a valid and precise measurement system to describe syndesmotic anatomy in 3 planes. Level of Evidence: Level IV.

3-D Morphology Prediction of Progressive Spinal Deformities From Probabilistic Modeling of Discriminant Manifolds

We introduce a novel approach for predicting the progression of adolescent idiopathic scoliosis from 3-D spine models reconstructed from biplanar X-ray images. Recent progress in machine learning has allowed to improve classification and prognosis rates, but lack a probabilistic framework to measure uncertainty in the data. We propose a discriminative probabilistic manifold embedding where locally linear mappings transform data points from high-dimensional space to corresponding low-dimensional coordinates. A discriminant adjacency matrix is constructed to maximize the separation between progressive (P) and nonprogressive (NP) groups of patients diagnosed with scoliosis, while minimizing the distance in latent variables belonging to the same class. To predict the evolution of deformation, a baseline reconstruction is projected onto the manifold, from which a spatiotemporal regression model is built from parallel transport curves inferred from neighboring exemplars. Rate of progression is modulated from the spine flexibility and curve magnitude of the 3-D spine deformation. The method was tested on 745 reconstructions from 133 subjects using longitudinal 3-D reconstructions of the spine, with results demonstrating the discriminatory framework can identify between P and NP of scoliotic patients with a classification rate of 81% and the prediction differences of 2.1° in main curve angulation, outperforming other manifold learning methods. Our method achieved a higher prediction accuracy and improved the modeling of spatiotemporal morphological changes in highly deformed spines compared with other learning methods.

Modification of Distal Tibiofibular Relationship After a Mild Syndesmotic Injury.

Background. The hypothesis of this study is that a sprain or tear of 1 or more of the 3 syndesmotic ligaments will result in a significant change in the osseous anatomy relationship when comparing injured to uninjured syndesmosis. Our secondary objective was to determine whether injuries to the syndesmosis as diagnosed on magnetic resonance imaging (MRI) could be found using static imaging. Methods. This is a descriptive radiological study of ankle MRI reports over a 12-year period, from 2 different institutions, and divided in two groups: normal and injured syndesmotic ligaments. A series of 6 lengths and 2 angles were measured on MRI axial views that describe the rotation, lateral, and anteroposterior translational relation between the distal tibia and fibula. Parameters from injured and uninjured ankles were compared using Student’s t-test. Results. Fifty uninjured syndesmosis were compared to 64 injured syndesmoses. The majority of syndesmosis injuries concerned either an anterior inferior tibiofibular ligament sprain or tear. There was a significant difference in the anatomic position of the tibia and the fibula between injured and uninjured syndesmosis. Conclusions. The anterior inferior tibiofibular ligament is the most commonly injured ligament in the syndesmosis in sports injury and results in subtle variations in the syndesmotic anatomy, which plain radiographs cannot assess. Because of the previously validated computed tomography scan measurement, this study demonstrates a potential to identify syndesmotic injury on other more accessible imaging modalities, such as computed tomography scan, by using a well-defined measurement system. Levels of Evidence: Diagnostic, Level III : Retrospective, Radiologic Study

MRI Quantification of the Impact of Ankle Position on Syndesmosis Anatomy.

Background: Despite the common occurrence of syndesmotic injuries in ankle trauma, the distal tibiofibular relationship remains poorly understood. The aim of this study was to evaluate the anatomical impact of ankle sagittal positioning on the tibiofibular relationship in intact ankles by using a validated magnetic resonance imaging (MRI)–based measurement system. Methods: In this radiologic study, 34 healthy volunteers underwent a series of ankle MRIs with the ankle stabilized in 3 positions: neutral position (NP), dorsiflexion (DF), and plantarflexion (PF). Using a previously validated measurement system, 6 fixed translational measurements and 2 fixed angles were recorded on each MRI and compared using paired t tests. Results: When comparing PF to DF, the anterior distance between the tibial incisura and the fibula varied from 2.5 mm to 3.9 mm (P < .001), respectively. The middle distance between the tibial incisura and the fibula varied from 1.5 mm to 2.6 mm (P < .001). Fibular angle varied from 8.7 degrees to 7.8 degrees of internal rotation (P = .046), respectively. When comparing NP to DF, only the anterior distance was found to be significantly different, varying 0.4 mm (P < .002). Conclusions: Ankle dorsiflexion leads to an increase in external rotation and lateral translation of the fibula. These changes could be measured on MRI using a validated measurement system. Ankle motion did have an impact on the distal tibiofibular relationship and should be considered in studies pertaining to syndesmosis imaging. Clinical Relevance: This is the first in vivo study demonstrating the impact of sagittal ankle position on the distal tibiofibular relationship in an uninjured ankle. Our findings also support the practice of placing the ankle in dorsiflexion when fixing a disrupted syndesmosis. Level of Evidence: Level III, comparative study.

Evaluation and Management of Complications of Pediatric Femur Fractures

Complications associated with pediatric femur fractures vary according to the location of the fracture. Proximal femoral fractures of the head and neck account for less than 1 % of all pediatric fractures, and the most common complications are often severe, including femoral head osteonecrosis, premature physeal closure (and subsequent growth disturbance), fracture nonunion, coxa vara, infection, and chondrolysis. The most common femoral shaft fracture complications are malunion, leg-length discrepancy, and muscle weakness, with much rarer reporting of compartment syndrome, neurovascular injury, infection, and nonunion. The most frequent complications associated with distal femoral fractures are stiffness and growth disturbance, which may lead to angular deformity or leg-length discrepancy. Other reported complications are ligamentous injuries and neurovascular injuries. This chapter explores the evaluation and management of this array of complications, most of which can arise even with appropriate management of primary fractures.

Classification of Progressive and Non-progressive Scoliosis Patients Using Discriminant Manifolds

Adolescent idiopathic scoliosis (AIS) is a 3-D deformation of the spine. Identifying curve progression in AIS at the first visit is a clinically relevant problem but remains challenging due to lack of relevant descriptors. We present here a classification framework to identify patients whose spine deformity will progress from those who will remain stable. The method uses personalized 3-D spine reconstructions at baseline from progressive (P) and non-progressive (NP) patients to train a predictive model. Morphological changes between groups are detected using a manifold learning algorithm based on Grassmannian kernels in order to assess the similarity between shape topology and inter-vertebral poses in both groups (P, NP). We test the method to classify 52 progressive and 81 non-progressive patients enrolled in a prospective clinical study, yielding classification rates comparing favorably to standard classification methods.

My Experience as a Foot and Ankle Trauma Surgeon in Montreal, Canada: What's Not in the Books.

Foot and ankle fractures are sometimes seen as routine and easy to treat. However, many fractures vary from typical patterns and require more complex management. Obtaining good outcomes in these situations can be challenging. Often, the difference between average and good results has to do with preoperative planning and good surgical technique. This article outlines numerous techniques and tricks that are not always mentioned in classic textbooks. It focuses on ankle, talus, calcaneus, and midfoot fractures, and discusses numerous techniques and aids to avoid potential problems that may be encountered intraoperatively.