Unlockable knee joint mechanism for powered gait orthosis

Abstract

Walking with the knee joint locked increases the amplitude of pelvic tilt and results in an unnatural gait. This paper introduces a powered gait orthosis with a moveable knee joint designed to improve the gait speed of patients with spinal cord injury (SCI). The unlockable knee joint powered gait orthosis (UKJ-PGO) uses a gas spring cylinder and a solenoid locking device to enable flexion of the joint, while the rigidity of the hip-joint device is enhanced using air muscles. A gait analysis was conducted to evaluate the performance of the UKJ-PGO, and the kinematic parameters obtained were compared with those of a standard PGO. In the gait of SCI patients using the UKJ-PGO, the new knee-joint device enabled flexion during the swing phase and showed a decrease in pelvic tilt compared with the standard PGO gait. As greater flexion was possible at the knee joint, the duration of the stance phase substantially decreased to near to the normal value, and the duration of the swing phase increased accordingly. In addition, the gait using the UKJ-PGO was faster than that with the standard PGO.

Evaluation of a novel powered hip orthosis for walking by a spinal cord injury patient

“…4 However, RGOs have since formed the basic structure upon which most powered orthoses are designed today. 3,[5][6][7] The externally-applied force has previously been installed on the mechanical structure or exoskeleton using pneumatic, motorized, electric or hydraulic actuators. The high efficiency, smoothness and fast response of motoractivating actuators makes them more suitable for the application of power to RGO-type devices than other forms of force application.…”

The influence of orthosis options on walking parameters in spinal cord-injured patients: a literature review

“…In addition, an increase in temporal spatial parameters (speed of walking, cadence, step length) was reported with powered knee joints or unlock able knee joint compared with a mechanical orthosis (for example, IRGO, ARGO) in SCI patients. [30][31][32] In the modified knee joint category in using mechanical linked knee ankle joints, the value of the speed of walking reported 0.14 m per second. 29 Using powered knee joint associated with ARGO, IRGO had significant influence.…”

“…The rate of walking speed reported 0.53, 0.31 and 0.33 m per second. [30][31][32] Energy consumption was not evaluated when modified knee joint was used in the SCI patients. On the basis of knee extension position in the mechanical orthoses, reduction in compensatory motion is demonstrated by using powered orthosis 55 or IRGO with stance control knee joint in SCI patients.…”

“…Five studies investigated the role of knee joint options on gait parameters and compensatory trunk motion. [28][29][30][31][32] These studies had a low level of evidence according to the PEDro score (2/10). In an identifying paper, it has been shown that adding FES to knee extensor (quadriceps) muscles with the RGO system reduces heart rate and energy expend.…”

Sensor-based hip control with hybrid neuroprosthesis for walking in paraplegia

“…The R 2 GO reduced vertical displacement of the center of mass by 8 cm relative to that of an RGO in an individual with SCI and resulted in a more efficient pattern of horizontal pelvic rotation [10]. Other innovations involved the application of external power assistance to the RGO including direct current motors [11][12][13] and pneumatic artificial muscles [14] to help drive the reciprocal motion of the RGO. Such power-assisted RGOs decreased effort by users with SCI relative to walking with a standard RGO and have been shown to reduce the lateral and vertical compensatory motions involved in standard RGO gait [11,15].…”