Morgan Sangeux

University Children's Hospital Basel | UKBB · Department of Orthopaedics

Measurement of gait kinematic variability provides relevant clinical information in certain conditions affecting the neuromotor control of movement. In this article, we present a measure of overall gait kinematic variability, GaitSD, based on combination of waveforms' standard deviation. The waveform standard deviation is the common numerator in es...

Torsional deformities of the femur and tibia are associated with gait impairments and joint pain. Several studies have investigated these gait deviations in children with cerebral palsy. However, relatively little is known about gait deviations in children with idiopathic torsion and debate ensues about the management of these patients. Research q...

Background: The Conventional Gait Model (CGM), known by a variety of different names, is widely used in clinical gait analysis. We present pyCGM2, an open-source implementation of the CGM with two versions. The first, CGM1.0, is a clone of Vicon Plug In Gait (PiG) with all its variants. CGM1.0 provides a platform to test the effect of modification...

Pathologies of the hip affect its biomechanics and vice versa. There is a strong relationship between the shape and orientation of the proximal femur and acetabulum, and the capacity of the hip muscles to generate the moment required to achieve a movement. Conversely, the biomechanics of the musculoskeletal system during gait affects the kinematics...

The identification of musculoskeletal impairments from gait analysis in children with cerebral palsy is a complex task, as is formulating (surgical) recommendations. In this paper, we present how we built a decision support system based on gait kinematics, anthropometrics, and physical examination data. The decision support system was trained to le...

Virtual reality (VR), coupled with motion tracking, can investigate walking in a controlled setting while applying various walking challenges. The purpose of this review was to summarize the evidence on consequences of VR on biomechanical gait parameters in children with cerebral palsy. MEDLINE, Embase and Web of Science were searched. Among 7.574...

There is a lack of knowledge about the accuracy of the Conventional Gait Model (CGM), compared to the true bone motion. Accuracy is hindered by both marker misplacement and soft-tissue artefact (STA). The effect of the lateral knee marker (KNE) misplacement and STA was determined from a secondary analysis of 13 subjects equipped with a total knee p...

Background: Children with cerebral palsy develop foot deformities due to a combination of factors including muscle shortening, hypertonia, weakness, and cocontraction of muscles acting at the ankle joint resulting in an altered gait pattern. We hypothesized these factors affect the peroneus longus (PL) and tibialis anterior (TA) muscles couple in...

Background: The conventional gait model (CGM1) is extensively used for 3D clinical gait analysis. It uses lateral wand-mounted markers for the thigh and shank segments to avoid colinearity of the tracking markers. However, gait analysts may be tempted to use skin-mounted markers instead. Research question: Does it matter if the lateral markers f...

Background: Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are neurodevelopmental disorders in need of innovative 'real-world' outcome measures to evaluate treatment effects. Instrumented gait analysis (IGA) using wearable technology offers a potentially feasible solution to measure "real-world' neurological and motor dysfunction in these...

Background Children with spastic cerebral palsy gradually lose muscle extensibility but the interplay between the muscular and neurological components of the condition is unclear especially in the pathophysiology of equinovalgus gait. Aim This study aimed to quantify the muscular and neurological disorders in young children with unilateral cerebra...

Children with cerebral palsy (CP) exhibit delayed motor development and impaired motor function compared to typically developing (TD) peers. The gross motor function classification system (GMFCS) may be used to grade severity of their motor impairment [1] but GMFCS might not sufficiently capture delays in motor development. As stride time variabili...

Overuse injuries imply the occurrence of a repetitive or an increased load on a specific anatomical segment which is unable to recover from this redundant microtrauma, thus leading to an inflammatory process of tendons, physis, bursa, or bone. Even if the aetiology is controversial, the most accepted is the traumatic one. Limb malalignment has been...

Background Torsional deformities of the lower limbs in children and adolescents are a common cause of in-toeing gait and cause gait deviations. The purpose of this study was to examine the relationship of children and adolescents with suspected Idiopathic Torsional Deformities(ITD) and pain, gait function, activity and participation. Methods A ret...

The aim was to 1) determine intersession and intertrial reliability and 2) assess three sources of variability (intersubject, intersession and intertrial) of lower limb kinematic and electromyographic (EMG) variables during gait in toddlers with typical development (TD) and unilateral cerebral palsy (UCP) (age <3 years, independent walking experien...

Hospital-based gait analysis laboratories generally have a team of orthopaedic surgeons, biomedical engineers or clinical scientists, and physiotherapists (Baker, 2013). In this setting, the engineers are responsible for the continuous and smooth operation of the laboratory, including the collection and processing of high-quality video, motion capt...

Il s agit du document support de l'atelier," Biometrics" introduisant le projet Conventional Gait Model 2.

Background: Pedobarography software calculates the centre-of-pressure trajectory in relation to the foot to quantify foot contact patterns. This study presents two new pedobarography measures using the centre-of-pressure trajectory to assess heel rocker. Methods: To validate these pedobarography measures against 3D gait analysis, emed®-x and Vic...

Richard Baker et al. devised the Gait Profile Score (GPS) to measure the distance between a person’s gait pattern and that of a normative dataset. The GPS is the root mean square difference across time, planes, and joints between the person’s gait curves and the normative curves. However, Marks et al. showed that gait variables are collinear and th...

Three-dimensional gait analysis (3DGA) has not previously been considered by consensus panels of spinal cord experts for use in studies of patients with spinal cord damage (SCD), yet it is frequently used in other neurological populations, such as stroke and cerebral palsy. Research question How does 3DGA impairment based reporting guide individua...

Changes in joint architecture and muscle loading resulting from total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RSA) are known to influence joint stability and prosthesis survivorship. This study aimed to measure changes in muscle moment arms, muscle lines of action, as well as muscle and joint loading following TSA and R...

Background: The Conventional Gait Model (CGM), known by a variety of different names, is widely used in clinical gait analysis. We present pyCGM2, an open-source implementation of the CGM with two versions. The first, CGM1.0, is a clone of Vicon Plug In Gait (PiG) with all its variants. CGM1.0 provides a platform to test the effect of modifications...

The Conventional Gait Model (CGM) needs to benefit from large investigations on localization of the hip joint centre (HJC). Incorrect positions from the native equations were demonstrated (Sangeux et al., 2014; Harrington et al., 2007). More accurate equations were proposed but their impact on kinematics and kinetic CGM outputs was never evaluated....

Hip rotation kinematics during gait is a key parameter to support clinical decision making but is also one of the least repeatable because it is difficult to locate the position of the medio-lateral axis of the femur. I described a workflow to perform functional calibration using knee kinematics only, and adjust hip rotation and knee kinematics ret...

Background: The aim of this study was two-fold: (1) to quantify the variability of upper limb electromyographic patterns during elbow movements in typically developing children and children with unilateral spastic cerebral palsy, and to compare different amplitude normalization methods; (2) to develop a method using this variability to detect (a)...

Purpose Botulinum toxin-A (or Botox) is widely used for the management of equinus gait in children with cerebral palsy but few recent studies have included instrumented gait analysis. Methods This was a prospective cohort study. Gait analysis was performed four weeks before and four weeks after Botulinum toxin-A injection for spastic equinus to de...

Purpose Botulinum toxin-A (or Botox) is widely used for the management of equinus gait in children with cerebral palsy but few recent studies have included instrumented gait analysis. Methods This was a prospective cohort study. Gait analysis was performed four weeks before and four weeks after Botulinum toxin-A injection for spastic equinus to de...

Background: Rotator cuff tears following anatomic total shoulder arthroplasty increase with duration of follow-up. This study aimed to evaluate contact pressure between the rotator cuff tendons and prosthesis after anatomic total shoulder arthroplasty and compare these with the tendon-contact pressures in the native shoulder. Methods: Eight enti...

Hip rotation kinematics during gait is a key parameter to support clinical decision making, for example in children with lower limb torsional deformities. However, hip rotation kinematics is also one of the least repeatable parameter because it is difficult to locate the position of the medio-lateral axis of the femur. Functional knee calibration p...

Hip rotation during gait is a major indicator for femoral derotation osteotomy. However, repeatability of hip rotation is poor because of discrepancies in determining the medial-lateral axis of the femur. Combining 3D gait analysis with medical imaging allows in vivo evaluation of current clinical methods. We used the condylar axis, identified from...

Aim: We investigated the long-term efficacy and safety of multilevel surgery (MLS) in ambulatory children with bilateral spastic cerebral palsy (CP). Method: Two hundred and thirty-one children were evaluated at short term (1.1y, SD 0.4) and long term (9.1y, SD 3.0) follow-up using clinical examination and gait analysis. MLS was investigated by...

Introduction: Kinematics and kinetics during gait are used to inform surgical decision making. For example, hip rotation kinematics are considered the key measurement to decide to perform a femoral derotational osteotomy, and to predict surgical outcomes [1]. However, the accuracy and reliability of hip rotation kinematics has been shown to be the...

Individuals who suffered an anterior cruciate ligament injury (ACL) also often suffer from long-term consequences [1], and return to play can be as low as 55% [2]. Movement adaptations to avoid pain post injury / surgery can become habitual, well beyond rehabilitation, and might result in non-optimal movement pattern (e.g. asymmetries) that increas...

Introduction: Clinical decision making in orthopaedics from gait analysis may be complex. It primarily depends on the perceived impairment(s) that may be addressed with surgery. These impairments are assessed objectively from data such as kinematics, kinetics and physical examinations. The decision making process is complex because of the volume, a...

Introduction: Gait impairments are typically identified by clinicians using data from physical examination and three-dimensional gait analysis (3DGA). The quantity of information the clinicians have to synthesize can be substantial. Therefore, it is probable that the efficiency and accuracy of this process can be improved, if an automated system ca...

Introduction: After deciding on which orthopaedic operations to conduct on a patient, there are several reasons why we would like to predict the effect of the operation on the patient’s gait. For example, if the prediction shows an improvement is unlikely, then it might be prudent for the clinical team to reconsider their decision. On one hand, the...

Pedobarography and the centre of pressure (COP) progression is useful to understand foot function. Pedobarography is often unavailable in gait laboratories or completed asynchronously to kinematic and kinetic data collection. This paper presents a model that allows calculation of COP progression synchronously using force plate data. The model is an...

This zip file contains scripts to extract gait kinematics data from c3d files and to perform the statistical analysis described in Quantifying sources of variability in gait analysis, K. Chia and M. Sangeux, Gait & Posture 2017 [DOI: 10.1016/j.gaitpost.2017.04.040], on new data.

The Conventional Gait Model (CGM) is a generic name for a family of closely related and very widely used biomechanical models for gait analysis. After describing its history, the core attributes of the model are described followed by evaluation of its strengths and weaknesses. An analysis of the current and future requirements for practical biomech...

Measurements from gait analysis are affected by many sources of variability. Schwartz et al. [1] illustrated an experimental design and methods to estimate these variance components. However, the derivation contains errors which could severely bias the estimation of some components. Therefore, in this paper, we presented correction to this method u...

We used theory and empirical data to demonstrate three undesirable properties of the dimensionless normalisation technique for gait spatio-temporal parameters. Firstly, it may not fully remove the correlation between leg length and spatio-temporal parameters. Secondly, it induces spurious correlation among spatio-temporal parameters, which might ob...

Clinical gait analysis incorporating three-dimensional motion analysis plays a key role in planning surgical treatments in people with gait disability. The position of the Hip Joint Centre (HJC) within the pelvis is thus critical to ensure accurate data interpretation. The position of the HJC is determined from regression equations based on anthrop...

Functional calibration methods were devised to improve repeatability and accuracy of the knee flexion-extension axis, which is used to define the medio-lateral axis of the femur coordinate system in gait analysis. Repeatability of functional calibration methods has been studied extensively in healthy individuals, but not accuracy in the absence of...

Introduction Le centre articulaire de la hanche (CAH) du modèle conventionnel de marche (MCM), développé par Davis s’appuie sur des régressions construites à l’aide d’un faible nombre de pelvis. L’imprécision de cette régression a été constatée au moyen de l’imagerie médicale 3D. De nouvelles régressions sont disponibles, mais aucune ne quantifie l...

File description [aP, alphaP] = FitJointAxis(ProxName, DistName, type, mySide) INPUT: - ProxName: the name of the proximal segment Default: 'LFE' - DistName: the name of the distal segment Default: 'LTI' - type: the type of joint axis algorithm: - Default: '2DoF' for an equivalent of the DynaKAD method from Baker et al. 1999 - 'ATT' for the axis...

File description [Merr, xP, xD] = FitJointCentre(ProxName, DistName, type, DistMarkers, mySide) INPUT: - ProxName: the name of the proximal segment Default: 'PEL' - DistName: the name of the distal segment Default: 'LFE' - type: the type of joint centre algorithm: - Default: 'Geom' for sphere fitting - or 'CTT' for centre transformation technique...

Accurate calibration of the medio-lateral axis of the femur is crucial for clinical decision making based on gait analysis. This study proposes a protocol utilizing biplanar radiographs to provide a reference medio-lateral axis based on the anatomy of the femur. The biplanar radiographs allowed 3D modelling of the bones of the lower limbs and the m...

Ultrasound imaging is relatively inexpensive, does not involve ionising radiation, and requires much shorter scan times compared with other imaging modalities such as magnetic resonance imaging and computed tomography. These advantages make it an appealing option in both clinical and research settings. Computational models of the human musculoskele...

Sagittal plane alignment of the foot presents challenges when the subject wears shoes during gait analysis. Typically, visual alignment is performed by positioning two markers, the heel and toe markers, aligned with the foot within the shoe. Alternatively, software alignment is possible when the sole of the shoe lies parallel to the ground, and the...

Introduction: Soft tissue artefact (STA) is one of the main source of measurement error in gait analysis [1]. Thigh rotation is particularly affected by STA and contributes to inaccurate measurement of both hip and knee rotation kinematics. Wren et al. [2] proposed a model which used a skin marker located above the patella to better track rotation...

Hip rotation from gait analysis informs clinical decisions regarding correct of femoral torsional deformities. However, it is among the least repeatable due to discrepancies in determining the medial-lateral axis of the femur. Conventional or functional calibration methods may be used to define the axis but there is no benchmark to evaluate these m...