Analysis of the Applicability of an Ankle-Foot Orthosis during Gait in Poststroke Patients

Effect of heel pressure pad attached to ankle-foot orthosis on the energy conversion efficiency in post-stroke hemiplegic gait

[Purpose] This study aimed to analyze the effect of heel pads in ankle-foot orthoses on dynamic motion aspects of gait in stroke patients from the viewpoint of energy conversion efficiency. [Subjects] Fourteen chronic stroke patients who were ambulatory and had lower extremity motor function categorized as Brunnstrom stage IV participated in the study. [Methods] A three-dimensional motion analysis system was used to assess the effect of heel pad intervention on dynamic motion gait parameters using a single-system A-B-A design. [Results] The results showed that a heel pad attached to the ankle-foot orthosis caused significant retention of the center-of-pressure at the heel during the heel rocker function and significant increase in the dorsiflexion moment and the height of the center of gravity. [Conclusion] The present study showed that a heel pad attached to the calcaneal region of an ankle-foot orthosis caused slight retention of the center-of-pressure at the heel during the heel rocker function along with center of gravity elevation in the stance phase and improved the energy conversion efficiency, especially on the non-paretic side.

Changes in angular kinematics of the paretic lower limb at different orthotic angles of plantar flexion limitation of an ankle-foot-orthosis for stroke patients

[Purpose] An ankle-foot-orthosis (AFO) is an assistive brace that allows stroke patients to achieve an independent gait. Therefore, we examined whether or not the orthotic angle for plantar flexion limitation affects the kinematic parameters of the hip and knee joints on the affected side of patients with stroke. [Subjects and Methods] Fifteen patients with chronic hemiplegia were recruited for this study. Kinematic three-dimensional data was acquired, while patients walked along a walkway wearing AFOs under five different conditions of 0°, 5°, 10°, 15°, and 20° of plantar stop limitation angle in the orthotic joint. Peak angles of the hip and knee joints on the affected side were analyzed. [Results] At the peak angle of the knee joint, statistically significant differences were found only at mid-stance in the sagittal plane and the horizontal plane. However, no significant differences were observed among any of the orthotic limitation angles in the frontal plane. [Conclusion] According to the results, an orthotic limitation angle of more than 10° elicits changes in the knee joint angle at mid-stance in the sagittal and horizontal planes. This study provided basic data on postural changes of patients with stroke.

Accelerometer and gyroscope based gait analysis using spectral analysis of patients with osteoarthritis of the knee

[Purpose] A wide variety of accelerometer tools are used to estimate human movement, but there are no adequate data relating to gait symmetry parameters in the context of knee osteoarthritis. This study’s purpose was to evaluate a 3D-kinematic system using body-mounted sensors (gyroscopes and accelerometers) on the trunk and limbs. This is the first study to use spectral analysis for data post processing. [Subjects] Twelve patients with unilateral knee osteoarthritis (OA) (10 male) and seven age-matched controls (6 male) were studied. [Methods] Measurements with 3-D accelerometers and gyroscopes were compared to video analysis with marker positions tracked by a six-camera optoelectronic system (VICON 460, Oxford Metrics). Data were recorded using the 3D-kinematic system. [Results] The results of both gait analysis systems were significantly correlated. Five parameters were significantly different between the knee OA and control groups. To overcome time spent in expensive post-processing routines, spectral analysis was performed for fast differentiation between normal gait and pathological gait signals using the 3D-kinematic system. [Conclusions] The 3D-kinematic system is objective, inexpensive, accurate and portable, and allows long-term recordings in clinical, sport as well as ergonomic or functional capacity evaluation (FCE) settings. For fast post-processing, spectral analysis of the recorded data is recommended.