Development of a novel type of shoe to improve the efficiency of knee-ankle-foot orthoses with a medial single hip joint (Primewalk orthoses): a novel type of shoe for Primewalk orthosis.

The purpose of the study was to develop and evaluate a new heel cushion in shoes for use with knee-ankle-foot orthoses having a medial single hip joint (Primewalk orthoses) in order to improve walking velocity and efficiency. Primewalk orthoses and shoes were made for a 24-year-old man having paraplegia with flaccid paresis (level T-7; grade A, ASIA impairment scale) of 2 years' duration. Walking exercises were assigned. Shoes were modified with the sole made of hard rubber and the addition of soft rubber heel cushions. The walking speed, centre of foot pressure during walking, and ground reaction force were evaluated. The patient also subjectively assessed the devices. The modifications to the shoes resulted in a 1.94-fold increase in walking speed (8.6 to 16.7 m/min), a 1.87-fold increase in step length (16.7 to 31.3 cm) and a 54.8% decrease in the physiological cost index (7.7 to 3.48 beats/min). The centre of foot pressure during walking was found to deviate towards the lateral margin of the foot. The horizontal rotation of the pelvis increased simultaneously. The patient reported increased amplitude of flail motion of the trunk and decreased burden to the upper limbs. It was concluded that the modified new heel cushion of the shoe provided freedom to the lower legs and thereby increased walking efficiency.