Background The adjustment of plantarflexion resistive moment of an articulated ankle-foot orthosis is considered important in patients post stroke, but the evidence is still limited. Therefore, the aim of this study was to investigate the effect of changing the plantarflexion resistive moment of an articulated ankle-foot orthosis on ankle and knee joint angles and moments in patients post stroke. Methods Gait analysis was performed on 10 subjects post stroke under four different plantarflexion resistive moment conditions using a newly designed articulated ankle-foot orthosis. Data were recorded using a Bertec split-belt instrumented treadmill in a 3-dimensional motion analysis laboratory. Findings The ankle and knee sagittal joint angles and moments were significantly affected by the amount of plantarflexion resistive moment of the ankle-foot orthosis. Increasing the plantarflexion resistive moment of the ankle-foot orthosis induced significant decreases both in the peak ankle plantarflexion angle (P<0.01) and the peak knee extension angle (P<0.05). Also, the increase induced significant increases in the internal dorsiflexion moment of the ankle joint (P<0.01) and significantly decreased the internal flexion moment of the knee joint (P<0.01). Interpretation These results suggest an important link between the kinematic/kinetic parameters of the lower-limb joints and the plantarflexion resistive moment of an articulated ankle-foot orthosis. A future study should be performed to clarify their relationship further so that the practitioners may be able to use these parameters as objective data to determine an optimal plantarflexion resistive moment of an articulated ankle-foot orthosis for improved orthotic care in individual patients.

This study was undertaken to determine if prosthetic suspension capabilities of below-knee amputees could be improved by using biofeedback in a controlled exercise program. Improvements in muscle bulk of four amputees were assessed. Changes in transverse cross-sectional areas and suspension ability of the residual limb were measured. The effect of muscle training on gait and on muscle-use patterns during gait was observed. Marked increases in muscle bulk below the knee and improvement in suspension capabilities were seen in two of the subjects, and somewhat lesser improvements were seen in the remaining two subjects. From these changes, one could modify prosthetic designs to take advantage of the residual limb muscles for suspension. For this reason, training the below-knee amputee to exercise the residual limb musculature should become part of routine physical therapy management. In this study, biofeedback was proven to be a useful tool for the reeducation of the residual limb musculature.

Introduction Sensory feedback is largely unavailable for persons with upper-limb amputation with conventional prostheses. The current study created a portable vibratory haptic feedback system integrated into the prosthesis to test its usefulness in gripping objects during daily life. Materials and Methods Development involved optimizing a mapping algorithm between the force sensor and the feedback tactor vibration, developing a custom process for mounting a wireless force sensor onto the prosthetic thumb with reliable output, and developing an instrumented object for testing grip force accuracy. Clinical testing involved optimizing tactor placement, measuring grip force accuracy, measuring the ability to perform daily gripping tasks, and surveying prosthetic users' opinion of the system after using the vibratory haptic device at home. A total of six individuals with unilateral transradial amputation participated in this study. Results The results demonstrated optimal tactor placement more proximal versus distal on the forearm. Accuracy with haptic versus no haptic feedback demonstrated that haptic feedback improved the grip force accuracy by 129% (adjusted P = 0.041) for light grip force target (2 lb or 0.9 kg) in the nonportable system and 21% (adjusted P = 0.051) for medium grip force target (10 lb or 4.5 kg) in the portable system. Haptic feedback did not statistically improve grip accuracy at strong grip forces (20 lb or 9.1 kg). Haptic feedback improved the gripping technique during the Assessment of Capacity for Myoelectric Control (ACMC) by 1.22 points, although this was not statistically significant (P = 0.27, n = 4). The participants provided specific positive examples of how the vibratory haptic system was useful at home. The overall usability score was 3.6 where 4 indicated excellent and 0 indicated poor. Conclusions This kind of system has potential to improve the lives of upper-limb prosthetic users.