A preliminary study of the effect of restricted gastrocnemius length on foot kinematics and plantar pressure patterns during gait in children with Cerebral Palsy

 

Summary/conclusion

Kinematic foot modelling and pedobarography are complementary measurement methods for measuring foot biomechanics in children with cerebral palsy (CP). Pedobarography appears to be the most sensitive instrument measuring significantly decreased hindfoot and increased lateral forefoot mean plantar pressure and force in the children with gastrocnemius contracture, whilst the corresponding changes in foot kinematics were non-significant.

 

Introduction

Foot deformity is common in CP and is often due to hypertonia and contracture in spastic muscles. The aim of this study was to establish the repeatability of two measurement techniques and establish whether they could be used in the quantification of altered foot kinematics and kinetics that result from gastrocnemius contracture.

 

Method

The gait of 8 healthy children selected at random (5 girls, 3 boys, mean ± SD, 12 ± 3 yrs, range, 9-18 yrs) was tested twice using an EMED pedobarograph and a Vicon motion analysis system using the Oxford kinematic foot model to test the repeatability of the measurement methods and generate normal data. 8 children (4 girls, 4 boys, mean ± SD, 12 ± 2 yrs, range 8-15yr) with spastic CP and gastrocnemius contracture were subsequently tested using the same test protocol.

 

Results

Gastrocnemius contracture in children with CP significantly increased the mean pressure and force under the lateral forefoot during second rocker and reduced the mean pressure and force on the heel in first and second rockers. Gastrocnemius contracture produced an increase in peak hindfoot dorsiflexion, hindfoot eversion, forefoot dorsiflexion and forefoot supination in second rocker and reduced maximum hindfoot dorsiflexion in swing phase, but none of these differences were significant.