Detecting postoperative change in children with cerebral palsy: net nondimensional versus body mass oxygen normalization.

The aim of the study is to investigate whether the net nondimensional oxygen utilization scheme is able to detect postoperative improvement in the energy cost of walking in children with cerebral palsy and to compare it with a body mass normalization scheme. We evaluated 10 children with spastic cerebral palsy before and 9 months after equinus deformity surgery. Participants walked at a given speed of 2 km/hr and 3 km/hr on a treadmill. Oxygen utilization was measured, and mass relative VO₂ and net nondimensional VO₂ were calculated. Coefficient of variation was used for the description of variability among subjects. Postoperatively, gait kinematics normalized and the mass relative VO₂ and net nondimensional VO₂ showed significant improvement. Net nondimensional VO₂ is able to detect postoperative improvement with smaller variability among subjects than body mass related normalization in children with cerebral palsy.