Spinal Biomechanics Concepts of Pediatric Scoliosis and Trunk Shift Applied to Daily Tasks and Sports

The etiology of pediatric idiopathic scoliosis remains poorly understood and it is likely that there is a combination of different factors responsible for its initiation and development. Although the literature highlights the importance of mechanical factors on spinal deformations, the concepts did not receive the attention and consideration they deserve. The Cobb angle is the gold standard value to assess the extent of spinal deformations and risk of progression. However from a biomechanical perspective, it is not the Cobb angle that prevails but rather the distance from the vertebrae to the axis of an ideal straight vertical spine that is well seated and centered on the sacrum. These vertebral offsets along with asymmetrical loads are responsible for additional bending forces that may reach much higher values than the compression forces of a symmetric same load on a straight spine. Forces can be modified, amplified and redistributed by the shape of the spine alone. This article is a review of biomechanics concepts that are applied to the spine with simple concrete examples, and is addressed to clinicians and practitioners in orthopaedics, physical therapy, and sport and exercise science.