Objective: To establish a relationship between the scoliotic curve and the centre of gravity during level walking in patients diagnosed with adolescent idiopathic scoliosis.

Background data: There is no established aetiology for adolescent idiopathic scoliosis and the reasons for the progression of the curve are still unknown. But there is an agreement regarding multifactorial nature of the aetiology among many authors. One of the interesting factors suggested is asymmetry in the ground reaction forces during walking and their relation to the deformity, indicated by gait analysis studies. Studies have also indicated that the cause and progression of the deformity in idiopathic scoliosis may be due to kinematic differences in the spine, pelvis and lower limb. If a relation could be established between the scoliotic curve and the centre of gravity, it is possible to draw some conclusions regarding the aetiology. There is no method or study till date which looked at the relation of scoliotic curve with the centre of gravity.

Materials and Methods: Patients who were diagnosed with adolescent idiopathic scoliosis were selected. Informed consent was taken for gait analysis. 16 Markers were placed over the lower limb and force plate, using modified Helen Hays set. 5 markers were placed over the surface landmarks of selected spinous processes (C7, T6, T12, L3 and S2). Ground reaction forces and motion data were analysed, using APAS gait system and the lines of vectors were developed and correlated with the marker over the second sacral spinous process.

Results: With the help of this method we were able to establish a relationship between the scoliotic curve and centre of gravity line. These in turn were expressed in terms of changes in the moment in relation to the midline of the coronal plane. The results indicated that the changes were proportional to the severity of the scoliotic curve.

Conclusion: We present a new method of establishing the relation of scoliotic curve with the ground reaction force and the centre of gravity. Initial results obtained from this method indicate the asymmetries in the deviation of the centre of gravity line in relation to the curve, during walking. Ongoing studies based on this method, will help to understand the pathogenesis and aetiology of scoliosis on a biomechanical basis which can help in developing new treatment modalities and efficient management of these patients.

Background: To compare height-adjusted fat and fat-free mass components of body composition in girls with adolescent idiopathic scoliosis to young adolescents with eating disorders. Adolescent idiopathic scoliosis (AIS) has been linked with low bone densities. Animal and human studies have shown that bone densities are influenced by a wide variety of inter-related factors that includes body fat, oestrogen levels, nutritional status and energy balance. Anthropometric studies have reported girls with AIS as being taller and more slender than their age-matched peers and that they also exhibit complex patterns of body asymmetry, particularly in the upper limb. There are also some studies report eating disorders in this population.

Methods: Height-adjusted fat and fat-free mass components of body composition were examined. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated and normalised for height and were superimposed onto UK 1990 growth reference data. The data for left and right limb length was also compared. A sample of 325 girls with AIS referred to the specialist spinal unit in Liverpool during the period 1970–1990.

Results: The fat mass index and fat-free mass index were reduced in this sample of AIS subjects compared with normal reference children, but were similar to those diagnosed with eating disorders (anorexia nervosa). The cohort also exhibited significant upper limb asymmetry.

Conclusion: The findings suggest that this population has significantly low fat mass compared to normal, healthy reference values. Since fat mass reflects energy balance, nutritional status (possibly eating disorders) and is closely linked to endocrine function, the implications of reduced fat mass on growth, bone mass accretion and the aetiology of AIS merit further investigation.

Introduction and Objective: Although the causation and progression of adolescent idiopathic scoliosis (AIS) remains unclear, a recent review has highlighted a series of possible aetiological factors. Additionally, research investigations have indicated that the kinematic differences in various body segments may be a major contributing factor. The value of gait analysis systems employed to measure dynamic back movements in furthering understanding of spinal deformity has also been demonstrated by various studies. Research employing gait measurements have indicated asymmetries in the ground reaction forces and have suggested relationship between these asymmetries, neurological dysfunction and spinal deformity. This investigation, which formed part of a wider comprehensive study, was aimed at identifying asymmetries in lower limb kinematics and pelvic and back movements during level walking in scoliotic subjects that could be related to the spinal deformity.

Design and Methodology: The research employed a movement analysis system and a strain gauge force platform to estimate time domain kinetic parameters and other kinematic parameters in the lower extremities, pelvis and back. 16 patients with varying degrees of deformity, scheduled for surgery within a week took part in the study.

Results and conclusions: The findings have demonstrated the presence of asymmetries in kinetic parameters in the scoliotic subject and have also served to highlight the value of using kinetic and kinematic parameters in developing the understanding of the pathogenesis and aetiology of scoliosis. In addition, the results have also indicated that the variables identified in the study can be applied to initial screening and surgical evaluation of spinal deformities such as scoliosis. Further studies are being undertaken to validate these findings.