L’impact de l’instrumentation du rachis sur les efforts intervertébraux et articulaires aux membres inférieurs au cours de la marche chez les patients ayant une scoliose idiopathique adolescente

RESUMÉ La scoliose est une pathologie musclo-squelettique. Cette maladie peut affecter la mobilité du corps humain et causer des problématiques liées aux mouvements. L’évaluation des pathologies musculaires, tel que la scoliose, demeure problématique en clinique de réadaptation. En lien avec cette problématique, une méthode de quantification des efforts articulaires aux membres inférieurs pour le corps humain en mouvement a été développée. Cette quantification sera utile dans le domaine de réadaptation, elle pourrait aider dans la sélection d’un programme efficace et spécifique des exercices de rééducation pour chacune des articulations aux membres inférieurs et dans le développement d’un indicateur pour évaluer le confort ainsi que la qualité de la marche des patients scoliotiques. Dans ce contexte, ce mémoire présente le développement d’un modèle dynamique multi-corps du corps humain pour la quantification des efforts intervertébraux ainsi que des efforts articulaires à la hanche, au genou et à la cheville afin de comparer le comportement dynamique au cours de la marche entre des patients ayant une Scoliose Idiopathique Adolescente (SIA) en condition pré-post opératoire et des sujets sains. Ensuite, pour chaque articulation, les valeurs maximales, minimales ainsi que les amplitudes des couples et des forces latéraux, verticaux et antéro-postérieurs ont été analysés à l’aide d’un test ANOVA à un facteur. De plus, un test Tukey post-hoc a été utilisé pour analyser les différences entre les trois groupes de sujets. Au niveau des efforts intervertébraux, l’étude montre que les valeurs minimales du couple antéro-postérieur ont diminué après l'instrumentation du rachis de 31%, 27%, 28%, et 31% au niveau de L5-L4, L4-L3, L3-L2, et L2-L1 respectivement. Le couple médio-latérale a significativement augmenté après l'instrumentation du rachis de 52%, 54%, 52%, 52%, 47% et 50% au niveau de L4 L5, L4-L3, L3-L2, L2-L1, L1-T12 et T11- T12 respectivement. Les forces médio-latérale, verticale et antéro-postérieur étaient significativement différentes après la chirurgie au niveau lombaire et thoraco-lombaire. Ces résultats montrent que l'asymétrie de la balance gauche-droite de la scoliose lors de la marche a été partiellement corrigée après la chirurgie. Les résultats du couple antéro-postérieur ont montré une similitude entre les patients sains et post-opératoire au niveau lombaire. Cependant, le comportement des autres composantes n’est pas globalement similaire aux sujets sains, ce qui implique le besoin du suivi en réadaptation après l’instrumentation du rachis.----------ABSTRACT Scoliosis is a musculoskeletal pathology. This disease can affect the mobility of human body and cause problems related to movements. The evaluation of muscle diseases, such as scoliosis, remains problematic in rehabilitation clinic. To respond to this problem, a quantification method of the lower limbs joint efforts during gait has been developed. This quantification will be useful in rehabilitation; it could help to select specific postural rehabilitation exercises around each lower limb joint to develop indicators of quality and comfort during gait. In this context, this study presents the development of a dynamics multi-body model of the human body for the quantification of intervertebral, hip, knee and ankle joint efforts in order to compare the dynamic behavior during gait between patients with Adolescent Idiopathic Scoliosis with (AIS) before and after spine instrumentation and healthy subjects. Then, One-way ANOVA was performed for the maximum, the minimum and the range of medio-lateral, vertical and anteroposterior torques and forces at each joint of the lower limbs. When appropriate, a Tukey's post hoc was performed to determine the differences. Amongst the intervertebral efforts results, the minimal values of the normalized antero-posterior intervertebral torques significantly decreased after surgery by 31%, 27%, 28%, and 31% at the L5-L4, L4-L3, L3-L2, and L2-L1 joints, respectively. The magnitude of the normalized medio-lateral intervertebral torques significantly increased after surgery by 52%, 54%, 52%, 52%, 47%, and 50% at the L5-L4, L4-L3, L3-L2, L2-L1, L1-T12, and T12-T11 joints, respectively. The antero-posterior, medio-lateral and vertical forces were significantly different after surgery at lumbar and thoraco-lumbar level. These results show that the asymmetry in the left-right balance of the scoliotic patient during gait was partially rectified after surgery. The results of antero-posterior torques showed a similarity between healthy and post-op patients at the lumbar level. However, the behaviours were globally still not similar to healthy patients for the other components, supporting the need for physiotherapy follow-up using a tool quantifying the intervertebral efforts during gait. For the lower limbs joint efforts, the results show that the scoliotic patients have the same dynamic behavior as healthy subjects for medio-lateral and antero-posterior torques. However, these patients have a reduced medio-lateral force compared to healthy subjects at the hip, knee and ankle. The study showed no significant difference between the two groups of scoliotic subjects

Are the medio-lateral joint forces in the lower limbs different between scoliotic and healthy subjects during gait?

INTRODUCTION: The quantification of internal joint efforts could be essential in the development of rehabilitation tools for patients with musculo-skeletal pathologies, such as scoliosis. In this context, the aim of this study was to compare the hips joint mediolateral forces during gait, between healthy subjects and adolescents with left lumbar or thoracolumbar scoliosis (AIS), categorized by their Cobb angle (CA). MATERIAL AND METHODS: Twelve healthy subjects, 12 AIS with CA between 20° and 40° and 16 AIS in pre-operative condition (CA : > 40°) walked at 4 km/h on an instrumented treadmill. The experimental set-up include six infrared cameras allow the computation of the tridimensional (3D) angular displacement and strain gauges located under the motor-driven treadmill allow the computation of ground reaction forces (GRF). The hips joint mediolateral forces were calculated using a 3D inverse dynamic of human body. One-way ANOVA was performed for the maximum, the minimum and the range of medio-lateral forces at each joint of the lower limbs. When appropriate, a Tukey's post hoc was performed to determine the differences. RESULTS: The mediolateral forces were significantly lower at the right hip for AIS with CA between 20° and 40° compared to healthy subject. CONCLUSION: The spinal deformation leads to a reduced medio-lateral force at the right hip, which could gradually change the scheme of postural adjustments for AIS during gait. Further research on the quantification of the joint lower limb efforts should include the knee and ankle joints to evaluate the impact of spinal deformation on the lower limb dynamic behaviour in AIS patients