The effect of orthotic tuning on the energy cost of walking in children with cerebral palsy

Introduction Children with cerebral palsy (CP) often have to wear orthoses to help them walk. There is a growing body of evidence that orthotic tuning, that is, optimisation of the ground reaction forces in the lower limbs during walking, is recommended to ensure the maximum potential benefit for each child. Research demonstrates that orthoses can reduce the energy cost of walking for children with CP, but to-date there is no evidence as to whether this tuning process results in further energy efficiency or not [1]. Aim The aim of this research programme was to validate a method that would help to determine when an orthosis was optimised for each child; and then to investigate whether the use of orthoses that were optimally tuned for each child allowed a further reduction in energy cost during walking, compared with orthoses that had not been optimally tuned. Method A video vector system was used to allow visualisation of the alignment of ground reaction forces in relation to the lower limbs during walking. A simple measurement tool was validated that allowed quantification of the moment arm at the knee in stance, which was used to confirm when optimal alignment had occurred following orthotic tuning. The energy cost of walking was measured using the Total Heart Beat Index (THBI). Data were collected barefoot, with the original ‘un-tuned’ orthosis and with the final ‘tuned’ orthosis. Results Analysis of energy cost showed that for some children, energy cost was further reduced through orthotic tuning, but that this was not the case for all children. Preliminary findings suggest the influence of underlying level of disability, as determined by the GMFCS. Conclusion Orthotic tuning may help to reduce the energy cost of walking for some children with CP, especially those with greater levels of disability. Further studies with large participant numbers are warranted to further investigate this area