Simulation of unilateral equinus using an adjustable orthosis in children: design, feasibility and biomechanical effects.

BACKGROUND AND AIM: In order to increase understanding of the biomechanical consequences of equinus foot on gait, we developed an orthosis to induce an adjustable degree of unilateral equinus. The aim of this study was to evaluate its feasibility and consequences on 3D ankle kinematics and kinetics.

TECHNIQUE: 3D gait analysis was carried out in 10 healthy children without the orthosis, with the non-adjusted orthosis and with the orthosis adjusted to +10°, 0°, -10°, -20° of ankle dorsiflexion and maximum plantarflexion (MP). The amount of dorsiflexion at initial contact was close to the goniometric measurement. Significant kinematic and kinetic changes occurred at -10°, -20° and MP. The mean maximum equinus at initial contact -21.65° ± 4.17 and during stance -11.61° ± 4.82 were larger than those obtained with previous described devices.

DISCUSSION: Our device was easy-to-use and induced an adjustable, well tolerated equinus. It provides a new way to simulate equinus and its biomechanical consequences on gait.