Coefficient of friction, walking speed and cadence on slippery and dry surfaces: shoes with different groove depths.

Objective. The present study aimed to determine the coefficient of friction (COF), walking speed (WS) and cadence while walking on slippery and dry surfaces using shoes with different sole groove depths to predict likelihood of fall. Background. Design of shoe sole groove is crucial to prevent slipping during walking. Methods. 22 healthy young men (mean age 24.5, body mass index 22.5) volunteered for this semi-experimental study. Six different conditions of the test (combination of three shoes and two surfaces) were defined and the condition was repeated three times. In total, 396 trials (22 subjects × 3 groove depths × 2 surfaces × 3 times) were obtained for data analysis. COF was recorded by force platform at 1000 Hz and walking parameters recorded using 3D motion analysis with six infrared cameras at 200 Hz. Results. The highest COF was obtained from the deepest groove depth (5.0 mm) on both dry and slippery surfaces. The COF on slippery surfaces was significantly lower in comparison with dry surfaces. WS and cadence were not significantly different on dry and slippery surfaces. Conclusion. The deeper groove is better to prevent slipping because the COF increases by increasing the shoe sole groove depth. WS did not change on dry and slippery surfaces.

Sensory feedback add-on for upper-limb prostheses.

BACKGROUND AND AIM: Sensory feedback systems have been of great interest in upper-limb prosthetics. Despite tremendous research, there are no commercial modality-matched feedback systems. This article aims to introduce the first detachable and feedback add-on option that can be attached to in-use prostheses. TECHNIQUE: A sensory feedback system was tested on a below-elbow myoelectric prosthesis. The aim was to have the amputee grasp fragile objects without crushing while other accidental feedback sources were blocked. DISCUSSION: A total of 8 successful trials (out of 10) showed that sensory feedback system decreased the amputee's visual dependency by improving awareness of his prosthesis. Sensory feedback system can be used either as post-fabrication (prosthetic add-on option) or para-fabrication (incorporated into prosthetic design). The use of these direct feedback systems can be explored with a current prosthesis before ordering new high-tech prosthesis. Clinical relevance This technical note introduces the first attach/detach-able sensory feedback system that can simply be added to in-use (myo)electric prosthesis, with no obligation to change prosthesis design or components.

A low invasiveness patient's specific template for spine surgery.

Free-hand pedicle screw placement is still conventional in surgery, although it has potentially high risks. The surgical procedures such as pedicle screw placement are usually designed based on medical imaging, but during surgery, the procedures are not normally followed due to the fact that some points are missed in two-dimensional images and seen only during surgery. In this regards, some highly accurate computer-assisted systems have been proposed and are currently used. Moreover, it is possible to reduce or completely avoid hand working by applying modern digital technology. Therefore, using these technologies has remarkable advantages. In this study, we have presented a new approach of pedicle screw placement in the lumbar and sacral regions using a specific drill guide template. The template was created by additive manufacturing technology and was verified in a clinical study as well. The main aim of this research includes the following: design, analyze, manufacture and evaluate the accuracy of a new patient-specific drill guide template, for lumbar pedicle screw placement, and compare the template to the free-hand technique under fluoroscopy supervision. Our results show that the incidence of cortex perforation is substantially reduced compared to existing methods. Finally, we believe that this approach remarkably lowers the incidence of cortex perforation and could be potentially used in clinical applications, particularly in certain selected cases.

Design and development of a novel viscoelastic ankle-foot prosthesis based on the human ankle biomechanics.

BACKGROUND AND AIM: In the present study, a new approach was applied to design and develop a viscoelastic ankle-foot prosthesis. The aim was to replicate the intact ankle moment-angle loop in the normal walking speed. TECHNIQUE: The moment-angle loop of intact ankle was divided into four parts, and the appropriate models including two viscoelastic units of spring-damper mechanism were considered to replicate the passive ankle dynamics. The developed prototype was then tested on a healthy subject with the amputee gait simulator. The result showed that prosthetic ankle moment-angle loop was similar to that of intact ankle with the distinct four periods. DISCUSSION: The findings suggest that the prototype successfully provided the human ankle passive dynamics. Therefore, the viscoelastic units could imitate the four periods of a normal gait. CLINICAL RELEVANCE: The novel viscoelastic foot prosthesis could provide natural ankle dynamics in a gait cycle. Applying simple but biomechanical approach is suggested in conception of new designs for prosthetic ankle-foot mechanisms.

The evaluation of modified foot orthosis on muscle activity and kinetic in a subject with flexible flat foot : single case study.

BACKGROUND: Due to blocking of pronation/dorsiflexion in flexible flat foot and restriction of these movements in using the University of California Berkeley Laboratory orthosis, provided pressures in sole by the orthosis were increased. Therefore, this article describes the evaluation of modified foot orthosis with flexible structure in the management of individuals with flexible flat foot. CASE DESCRIPTION AND METHOD: The patient was a 21-year-old male who had symptomatic flat foot. The modified foot orthosis included movable surface and the outside structure. The modified foot orthosis was evaluated by standing foot X-ray, comfort rate, electromyography of leg muscle and vertical ground reaction force during walking. FINDINGS AND OUTCOMES: The modified foot orthosis improved the foot alignment and decreased the symptoms of flat foot with more comfort. Subtalar position by sub-maximum supination had higher position than neutral in sagittal plane. It may increase the muscle activity of peroneus longus by 7% compared to barefoot, and there was a decrease of 11% ground reaction force in mid stance. CONCLUSION: The result of this single case evaluation only proposed the feasibility of this modified insole as the orthotic treatment in flexible flat foot. Clinical relevance The modified foot orthosis, which is mobile in the midfoot, is an orthosis for walking and standing in subjects with flexible flat foot.

Effect of powered gait orthosis on walking in individuals with paraplegia.

BACKGROUND: The important purpose of a powered gait orthosis is to provide active joint movement for patients with spinal cord injury. OBJECTIVES: The aim of this study was to clarify the effect of a powered gait orthosis on the kinematics and temporal-spatial parameters in paraplegics with spinal cord injury. STUDY DESIGN: Quasi-experimental. METHODS: Four spinal cord injury individuals experienced gait training with a powered gait orthosis for a minimum of 6 weeks prior to participating in the following walking trials: walking with an isocentric reciprocating gait orthosis and walking with both separate and synchronized movements with actuated orthotic hip and knee joints in a powered gait orthosis. Specific parameters were calculated and compared for each of the test conditions. RESULTS: Using separate and synchronized actuated movement of the hip and knee joints in the powered gait orthosis increased gait speed and step length and reduced lateral and vertical compensatory motions when compared to the isocentric reciprocating gait orthosis, but there were no significant differences in these parameters. Using the new powered gait orthosis improved knee and hip joint kinematics. CONCLUSIONS: The powered gait orthosis increased speed and step length as well as hip and knee joint kinematics and reduced the vertical and lateral compensatory motions compared to an isocentric reciprocating gait orthosis in spinal cord injury patients. CLINICAL RELEVANCE: This new powered gait orthosis has the potential to improve hip and knee joint kinematics, the temporal-spatial parameters of gait in spinal cord injury patients walking.