Reliability of pediobarographs for paediatric foot deformity.

PURPOSE

Dynamic pediobarograph measures foot-floor contact pressure during walking and provides a quantitative functional assessment. The goal of this study was to assess the reliability of pediobarograph measurements in normal children and in those with cerebral palsy (CP).

MATERIALS AND METHODS

During the first investigation, five non-disabled children and four with CP had three pediobarograph measurements taken of each foot, repeated five times. The pediobarographs were analysed by dividing the foot into five segments; the heel, the lateral midfoot, the medial midfoot, the lateral forefoot and the medial forefoot. A measure of valgus/varus foot posture was defined as the relative medial-lateral difference of combined mid- and forefoot impulse, named valgus/varus index. During the second investigation, 50 children (100 feet) with spastic diplegic CP were studied to calculate the standard error of measurements (SEM), to investigate the number of pediobarograph measurements necessary to obtain accurate results. The third investigation was an inter- and intraobserver study performed on one normal subject's repeated measurements.

RESULTS

In the first investigation, the group with CP had a significantly increased variability in the medial midfoot (P = 0.013). The variability of the valgus/varus index had a standard deviation of 13%, demonstrating that this measure is relatively stable. The SEM and 95% confidence interval from the second experiment showed that, even if the accuracy increased with the number of measurements, the greatest gain seemed to be contributed by increasing the number of measurements from 3 to 6. The inter- and intraobserver study showed good to mostly excellent agreement.

CONCLUSION

Pediobarograph measurements can be used to monitor and quantitatively assess the progressive changes of foot deformity over time. Pediobarograph is a reliable measurement that shows little variability between measurements at the same occasion and between measurements on different days. Three to six measurements seems practical and adequate to obtain. The technical aspect of measuring shows good repeatability and agreement between observers.