Comparing walking with knee-ankle-foot orthoses and a knee-powered exoskeleton after spinal cord injury: a randomized, crossover clinical trial

Abstract

Recovering the ability to stand and walk independently can have numerous health benefits for people with spinal cord injury (SCI). Wearable exoskeletons are being considered as a promising alternative to conventional knee-ankle-foot orthoses (KAFOs) for gait training and assisting functional mobility. However, comparisons between these two types of devices in terms of gait biomechanics and energetics have been limited. Through a randomized, crossover clinical trial, this study compared the use of a knee-powered lower limb exoskeleton (the ABLE Exoskeleton) against passive orthoses, which are the current standard of care for verticalization and gait ambulation outside the clinical setting in people with SCI. Ten patients with SCI completed a 10-session gait training program with each device followed by user satisfaction questionnaires. Walking with the ABLE Exoskeleton improved gait kinematics compared to the KAFOs, providing a more physiological gait pattern with less compensatory movements (38% reduction of circumduction, 25% increase of step length, 29% improvement in weight shifting). However, participants did not exhibit significantly better results in walking performance for the standard clinical tests (Timed Up and Go, 10-m Walk Test, and 6-min Walk Test), nor significant reductions in energy consumption. These results suggest that providing powered assistance only on the knee joints is not enough to significantly reduce the energy consumption required by people with SCI to walk compared to passive orthoses. Active assistance on the hip or ankle joints seems necessary to achieve this outcome.

Multicentric investigation on the safety, feasibility and usability of the ABLE lower-limb robotic exoskeleton for individuals with spinal cord injury: a framework towards the standardisation of clinical evaluations

“…However, another clinical study comparing the knee-powered ABLE Exoskeleton with Knee-Ankle-Foot orthoses (KAFOs) found no significant difference of performance in these walking tests. This study proposes that providing powered assistance only on the knee joints is not enough to provide sufficient trunk stability and reduced metabolic costs [ 11 ]. We also identified the lack of trunk stability in cervical and high thoracic lesions, but also the presence of spasticity in leg muscles and missing proprioception as main factors limiting the exoskeleton therapy outcome.…”

“…Due to the passive hip joints of the exoskeleton, in people with no or very limited voluntary hip movements, hip flexion is generated by forward-rotational movement of the pelvis. An analysis of the gait pattern used whilst walking with the ABLE exoskeleton has been analysed in a previous study [ 11 ]. Note that the aim of having the different walking modes is to adapt the exoskeleton to the users' needs.…”

Randomized, Crossover Clinical Trial on the Safety, Feasibility, and Usability of the ABLE Exoskeleton: A Comparative Study with Knee-Ankle-Foot Orthoses

“…After the final evaluation session (i.e., session 10), participants answered the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0) [43] and the Psychosocial Impact of Assistive Devices Scale (PIADS) [44] questionnaires to evaluate users' satisfaction and psychosocial impact, respectively, that the training with the corresponding device may have had. Results from the questionnaires were presented previously in [33]. Finally, four weeks after the final evaluation session, a follow-up phone call was conducted to monitor any issues that may have occurred.…”

“…However, comparisons supporting their superiority over conventional passive orthoses to assist locomotion are still scarce. Only a few studies aimed to compare wearable exoskeletons and passive orthoses; however, their main focus was on the comparison of functional performance, energy consumption, and/or patient satisfaction using each of the two systems [27][28][29][30][31][32][33]. Thus, the safety, feasibility, and usability of wearable exoskeletons have never been compared to those of passive orthoses, such as KAFOs.…”

“…We conducted a randomized, crossover clinical trial comparing the use of conventional KAFOs against a robotic knee-powered lower limb exoskeleton (i.e., the ABLE Exoskeleton) for gait training in people with SCI. The primary outcome measure of the clinical trial was the metabolic cost of walking using both devices, which was already assessed in [33]. The main objective of the present study was to evaluate the safety, feasibility, and usability of the ABLE Exoskeleton in a rehabilitation clinical setting.…”