Cerebral palsy with dislocated hip and scoliosis: what to deal with first?

Purpose: Hip dislocation and scoliosis are common in children with cerebral palsy (CP). Hip dislocation develops in 15% and 20% of children with CP, mainly between three and six years of age and especially in the spastic and dyskinetic subtypes. The risk of scoliosis increases with age and increasing disability as expressed by the Gross Motor Function Score. Methods: A hip surveillance programme and early surgical treatment have been shown to reduce the hip dislocation, but it remains unclear if a similar programme could reduce the need for neuromuscular scoliosis. When hip dislocation and neuromuscular scoliosis are co-existent, there appears to be no clear guidelines as to which of these deformities should be addressed first: hip or spine. Results: Hip dislocation or windswept deformity may cause pelvic obliquity and initiate scoliosis, while neuromuscular scoliosis itself leads to pelvic obliquity and may increase the risk of hip dislocation especially on the high side. It remains unclear if treating imminent hip dislocation can prevent development of scoliosis and vice versa, but they may present at the same time for surgery. Current expert opinion suggests that when hip dislocation and scoliosis present at the same time, scoliosis associated pelvic obliquity should be corrected before hip reconstruction. If the patient is not presenting with pelvic obliquity the more symptomatic condition should be addressed first. Conclusion: Early identification of hip displacement and neuromuscular scoliosis appears to be important for better surgical outcomes

Can developmental trajectories in gait variability provide prognostic clues in motor adaptation among children with mild cerebral palsy? A retrospective observational cohort study

AimTo investigate whether multiple domains of gait variability change during motor maturation and if this change over time could differentiate children with a typical development (TDC) from those with cerebral palsy (CwCP).MethodsThis cross-sectional retrospective study included 42 TDC and 129 CwCP, of which 99 and 30 exhibited GMFCS level I and II, respectively. Participants underwent barefoot 3D gait analysis. Age and parameters of gait variability (coefficient of variation of stride-time, stride length, single limb support time, walking speed, and cadence; as well as meanSD for hip flexion, knee flexion, and ankle dorsiflexion) were used to fit linear models, where the slope of the models could differ between groups to test the hypotheses.ResultsMotor-developmental trajectories of gait variability were able to distinguish between TDC and CwCP for all parameters, except the variability of joint angles. CwCP with GMFCS II also showed significantly higher levels of gait variability compared to those with GMFCS I, these levels were maintained across different ages.InterpretationThis study showed the potential of gait variability to identify and detect the motor characteristics of high functioning CwCP. In future, such trajectories could provide functional biomarkers for identifying children with mild movement related disorders and support the management of expectations

EPIPHYSIODESES PERCUTANEES. EVALUATION DE LA TECHNIQUE A MOYEN ET LONG TERME 30 PATIENTS FACE A LA LITTERATURE

PARIS6-Bibl. St Antoine CHU (751122104) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Optimisation de l'évaluation globale de l'enfant atteint de paralysie cérébrale à potentiel de marche (intégration de la qualité de vie liée à la santé et des capacités et performances dans le domaine de la vie quotidienne)

La prise en charge des enfants atteints de paralysie cérébrale (PC) est devenue multidisciplinaire. Pour le chirurgien la finalité du geste est d améliorer l état fonctionnel du patient, mais comment en juger ? La vie de tous les jours du patient a-t-elle été modifiée ? Dans une première partie théorique il s agissait de faire le point sur les composantes lors de la réalisation d une évaluation globale des enfants PC, d identifier les méthodes existantes et d apporter des réponses supplémentaires aux outils et connaissances existants. Puis dans une seconde partie pratique deux projets dans le cadre de cette évaluation globale de l enfant PC sont présentés : - le premier projet nous a permis d appliquer ces connaissances acquises dans le cadre de la conceptualisation, la réalisation et l analyse d un projet multicentrique, - le second projet rapporte les démarches de la création et l étude préliminaire d un nouvel outil d évaluation des capacités et performances de la vie quotidienne.Treatment in cerebral palsy (CP) children is now multidisciplinary. Outcome objectives for orthopaedic surgeons changed and are now to improve the patient s functional status. But how to evaluate the outcome ? Was patient s daily life improved ? In a first theoretical part the components of a global outcome assessment in CP patients were reviewed, existing methods identified and detected tools and knowledge were supplemented. In a second part two projects were presented based on the principles of global assessment : - the first project to apply the acquired knowledge in terms of conceptualisation, realisation and analysis of a multicenter project, - the second to create and study preliminarily a new tool to evaluate daily life capacities and performances in CP patients.AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocSudocFranceF

Subject specific muscle synergies and mechanical output during cycling with arms or legs

International audienceUpper (UL) and lower limb (LL) cycling is extensively used for several applications, especially for rehabilitation for which neuromuscular interactions between UL and LL have been shown. Nevertheless, the knowledge on the muscular coordination modality for UL is poorly investigated and it is still not known whether those mechanisms are similar or different to those of LL. The aim of this study was thus to put in evidence common coordination mechanism between UL and LL during cycling by investigating the mechanical output and the underlying muscle coordination using synergy analysis. Methods. Twenty-five revolutions were analyzed for six non-experts' participants during sub-maximal cycling with UL or LL. Crank torque and muscle activity of eleven muscles UL or LL were recorded. Muscle synergies were extracted using nonnegative matrix factorization (NNMF) and group-and subject-specific analysis were conducted. Results. Four synergies were extracted for both UL and LL. UL muscle coordination was organized around several mechanical functions (pushing, downing, and pulling) with a proportion of propulsive torque almost 80% of the total revolution while LL muscle coordination was organized around a main function (pushing) during the first half of the cycling revolution. LL muscle coordination was robust between participants while UL presented higher interindividual variability. Discussion. We showed that a same principle of muscle coordination exists for UL during cycling but with more complex mechanical implications. This study also brings further results suggesting each individual has unique muscle signature

One- and multi-segment foot models lead to opposite results on ankle joint kinematics during gait: Implications for clinical assessment

International audienceBackground: Biomechanical models representing the foot as a single rigid segment are commonly used in clinical or sport evaluations. However, neglecting internal foot movements could lead to significant inaccuracies on ankle joint kinematics. The present study proposed an assessment of 3D ankle kinematic outputs using two distinct biomechanical models and their application in the clinical flat foot case. Methods: Results of the Plug in Gait (one segment foot model) and the Oxford Foot Model (multisegment foot model) were compared for normal children (9 participants) and flat feet children (9 participants). Repeated measures of Analysis of Variance have been performed to assess the Foot model and Group effects on ankle joint kinematics. Findings: Significant differences were observed between the two models for each group all along the gait cycle. In particular for the flat feet group, opposite results between the Oxford Foot Model and the Plug in Gait were revealed at heelstrike, with the Plug in Gait showing a 4.7 degrees ankle dorsal flexion and 2.7 degrees varus where the Oxford Foot Model showed a 4.8 degrees ankle plantar flexion and 1.6 degrees valgus. Interpretation: Ankle joint kinematics of the flat feet group was more affected by foot modeling than normal group. Foot modeling appeared to have a strong influence on resulting ankle kinematics. Moreover, our findings showed that this influence could vary depending on the population. Studies involving ankle joint kinematic assessment should take foot modeling with caution. (C) 2015 Elsevier Ltd. All rights reserved

Increased Femoral Anteversion Does Not Lead to Increased Joint Forces During Gait in a Cohort of Adolescent Patients

Orthopedic complications were previously reported for patients with increased femoral anteversion. A more comprehensive analysis of the influence of increased femoral anteversion on joint loading in these patients is required to better understand the pathology and its clinical management. Therefore, the aim was to investigate lower-limb kinematics, joint moments and forces during gait in adolescent patients with increased, isolated femoral anteversion compared to typically developing controls. Secondly, relationships between the joint loads experienced by the patients and different morphological and kinematic features were investigated. Patients with increased femoral anteversion (n = 42, 12.8 ± 1.9 years, femoral anteversion: 39.6 ± 6.9°) were compared to typically developing controls (n = 9, 12.0 ± 3.0 years, femoral anteversion: 18.7 ± 4.1°). Hip and knee joint kinematics and kinetics were calculated using subject-specific musculoskeletal models. Differences between patients and controls in the investigated outcome variables (joint kinematics, moments, and forces) were evaluated through statistical parametric mapping with Hotelling T2 and t-tests (α = 0.05). Canonical correlation analyses (CCAs) and regression analyses were used to evaluate within the patients’ cohort the effect of different morphological and kinematic predictors on the outcome variables. Predicted compressive proximo-distal loads in both hip and knee joints were significantly reduced in patients compared to controls. A gait pattern characterized by increased knee flexion during terminal stance (KneeFlextSt) was significantly correlated with hip and knee forces, as well as with the resultant force exerted by the quadriceps on the patella. On the other hand, hip internal rotation and in-toeing, did not affect the loads in the joints. Based on the finding of the CCAs and linear regression analyses, patients were further divided into two subgroups based KneeFlextSt. Patients with excessive KneeFlextSt presented a significantly higher femoral anteversion than those with normal KneeFlextSt. Patients with excessive KneeFlextSt presented significantly larger quadriceps forces on the patella and a larger posteriorly-oriented shear force at the knee, compared to patients with normal KneeFlextSt, but both patients’ subgroups presented only limited differences in terms of joint loading compared to controls. This study showed that an altered femoral morphology does not necessarily lead to an increased risk of joint overloading, but instead patient-specific kinematics should be considered

The John Insall Award No Functional Benefit After Unicompartmental Knee Arthroplasty Performed With Patient-specific Instrumentation: A Randomized Trial

International audienceBackground Component alignment can influence implant longevity as well as perhaps pain and function after uni-compartmental knee arthroplasty (UKA), but correct alignment is not consistently achieved. To increase the likelihood that good alignment will be achieved during surgery, smart tools such as robotics or patient-specific instrumentation (PSI) have been introduced. Questions/purposes We hypothesized that UKA performed with PSI would result in improved level gait as ascertained with three-dimensional analysis, implant positioning, and patient-reported outcomes measured by a validated scoring system when compared with conventional instrumentation 3 months and 1 year after surgery. Methods We randomized 60 patients into two groups using either the PSI technique or a conventional technique. All patients were operated on using the same technique and the same cemented metal-backed implant. Mean age of the patients was 63 +/- 4 years (range, 54-72 years) and mean body mass index was 28 +/- 3 kg/m(2). Patients were evaluated preoperatively, at 3 months, and 1 year after surgery by an independent observer blind to the type of technique. Gait parameters were assessed with three-dimensional analysis during level walking preoperatively and at 1 year, frontal and sagittal position of the implant was evaluated on full-length radiographs at 3 months, and subjective functional outcome and quality of life using routine questionnaires (SF-12, new Knee Society Score [KSS], Knee Injury and Osteoarthritis Outcome Score) at 3 months and 1 year. This study had 80% power to detect a 15% difference in walking speed at the p<0.05 level. Results One year after surgery, there were no differences between the two groups in the analyzed gait spatiotemporal parameters, respectively, for PSI UKA and conventional UKA : double limb support 31% (25%-54%) versus 30% (23%-56%; p = 0.67) and walking speed (1.59 m/s [0.86-1.87 m/s] versus 1.57 m/s [0.71-1.96 m/s]; p = 0.41). No difference was observed between the two groups in terms of lower limb alignment (PSI group 178 degrees +/- 3 degrees, conventional group 178 degrees +/- 4 degrees; p = 0.24) or implant positioning on mediolateral and anteroposterior radiographs. There were no differences in the functional score between the PSI and conventional TKA groups at 3 months and 1 year after surgery: KSS objective knee scores (PSI: 85 +/- 8 points at 3 months, 87 +/- 5 points at 1 year and conventionalinstrumentation: 82 +/- 8 points at 3 months 83 +/- 6 points at 1 year; p = 0.10) and functional activity scores were similar in both group (PSI: 71 +/- 12 points at 3 months and 74 +/- 7 points at 1 year versus conventional group: 73 +/- 11 points at 3 months and 75 +/- 6 at 1 year; p = 0.9). Conclusions Our observations suggest that PSI may confer small, if any, advantage in alignment, pain, or function after UKA. This argument can therefore not be used to justify the extra cost and uncertainty related to this technique. Level of Evidence Level I, therapeutic study

Altered Muscle Contributions are Required to Support the Stance Limb During Voluntary Toe-Walking

Toe-walking characterizes several neuromuscular conditions and is associated with a reduction in gait stability and efficiency, as well as in life quality. The optimal choice of treatment depends on a correct understanding of the underlying pathology and on the individual biomechanics of walking. The objective of this study was to describe gait deviations occurring in a cohort of healthy adult subjects when mimicking a unilateral toe-walking pattern compared to their normal heel-to-toe gait pattern. The focus was to characterize the functional adaptations of the major lower-limb muscles which are required in order to toe walk. Musculoskeletal modeling was used to estimate the required muscle contributions to the joint sagittal moments. The support moment, defined as the sum of the sagittal extensive moments at the ankle, knee, and hip joints, was used to evaluate the overall muscular effort necessary to maintain stance limb stability and prevent the collapse of the knee. Compared to a normal heel-to-toe gait pattern, toe-walking was characterized by significantly different lower-limb kinematics and kinetics. The altered kinetic demands at each joint translated into different necessary moment contributions from most muscles. In particular, an earlier and prolonged ankle plantarflexion contribution was required from the soleus and gastrocnemius during most of the stance phase. The hip extensors had to provide a higher extensive moment during loading response, while a significantly higher knee extension contribution from the vasti was necessary during mid-stance. Compensatory muscular activations are therefore functionally required at every joint level in order to toe walk. A higher support moment during toe-walking indicates an overall higher muscular effort necessary to maintain stance limb stability and prevent the collapse of the knee. Higher muscular demands during gait may lead to fatigue, pain, and reduced quality of life. Toe-walking is indeed associated with significantly larger muscle forces exerted by the quadriceps to the patella and prolonged force transmission through the Achilles tendon during stance phase. Optimal treatment options should therefore account for muscular demands and potential overloads associated with specific compensatory mechanisms

Reply to the Letter to the Editor: The John Insall Award: No Functional Benefit After Unicompartmental Knee Arthroplasty Performed With Patient-specific Instrumentation: A Randomized Trial

International audienceno abstrac