Impact of foot orthosis design on gait in children with Charcot-Marie-Tooth

Charcot-Marie-Tooth disease (CMT) is a progressive neuromuscular disease resulting in mostly distal sensory deficit and muscular weakness. Most children with CMT also develop hard and soft foot deformities leading to pes cavus [1]. Foot orthoses (FO) are widely prescribed in CMT to support the foot arch and to improve gait, but there is a lack of guidelines to support their conception [2]. The aim of this pilot study was to assess the effect of FO (FOmax), which are made based on full and objective foot deformities evaluation (hard and soft deformities), on gait in children with CMT. This study included 8 children with CMT. Participants were provided with a classic pair of FO (FOclass) and a pair of FOmax. The latter were made based on measurement protocol of the foot deformities, including joints range of motion. FOmax conception considered that rigid deformities must be supported but not all the soft ones. A 3D gait analysis was performed with each type of FO after the participants wore the FO for 3 months. Plantar pressure was measured for each type of FO, using insole pressure sensor. Walking speed, step length, and time of single stance increased with FOmax compared to FOclass (p<0.05). Hip flexion/extension range of motion during stance increased with FOmax (p<0.05). Hip flexion at initial contact did not increase significantly (FOclass 32.8±5.7°; FOmax 35.4±6.2°, p=0.10). Insole pressure measurements could be analyzed in each condition for only 11 feet. For eight feet, peak pressure integral time during stance was lower with FOmax than with FOclass. These preliminary results suggest that children with CMT could take advantage of FOmax for walking. The increase in the step length could be related to the increase in the hip range of motion. The increase in the walking speed as well as the time of single support could result from a better repartition of the plantar foot pressure that optimizes children’s confidence during walking. The present results need to be confirmed with a larger sample size.