The relationship between tight hamstrings and lumbar hypolordosis in children with cerebral palsy

Study Design. Retrospective clinical and radiographic review. Objective. To assess the influence of tight hamstrings an the sagittal alignment of the thoracic and lumbar spine in children with cerebral palsy. Summary of Background Data. It is postulated that tight hamstrings may produce a hypolordosis of the lumbar spine. The abnormal sagittal contour of the spine may lead to increased stresses in the lumbar spine and subsequent pain and disability. This is of special concern in children with cerebral palsy who often have shortened spastic hamstring muscles. Method. Twenty-one patients were evaluated, with a mean age of 9.4 years. Standing and sitting lateral spine films were obtained and the lumbar lordosis and thoracic kyphosis were measured using the Cobb method. The popliteal angle was measured to assess hamstring tightness, such that a large popliteal angle indicates tight ham-strings. Results. We found a statistically significant correlation between the sitting lumbar curve and popliteal angle (Pearson correlation value -0.77, P < 0.01). As the popliteal angle increased, the amount of lumbar lordosis decreased This correlation was less significant when the patient was standing (Pearson correlation value -0.59). Conclusion. This study demonstrates that there is a correlation between tight hamstrings, as measured by the popliteal angle, and decreasing lumbar lordosis, especially when sitting.