In this study, a 3D model of a transtibial monolimb and residual limb was constructed. The stresses on all nodes of the model under the simulus of the load at the Mid-Stance were computed through 3D finite element analysis (FEA). The stress distribution on the internal and external surfaces of the model was obtained. The results indicate that the stresses on socket are lower than those on prosthetic shank; high stress regions are located on the underneath of prosthetic shank and the border section of socket and prosthetic shank. These data will be useful for CAD\CAM system of monolimb designing.
Artificial Limbs ; Finite Element Analysis ; Stress, Mechanical

Wearing transfemoral prosthesis is the only way to complete daily physical activity for amputees. Motion pattern recognition is important for the control of prosthesis, especially in the recognizing swing phase and stance phase. In this paper, it is reported that surface electromyography (sEMG) signal is used in swing and stance phase recognition. sEMG signal of related muscles was sampled by Infiniti of a Canadian company. The sEMG signal was then filtered by weighted filtering window and analyzed by height permitted window. The starting time of stance phase and swing phase is determined through analyzing special muscles. The sEMG signal of rectus femoris was used in stance phase recognition and sEMG signal of tibialis anterior is used in swing phase recognition. In a certain tolerating range, the double windows theory, including weighted filtering window and height permitted window, can reach a high accuracy rate. Through experiments, the real walking consciousness of the people was reflected by sEMG signal of related muscles. Using related muscles to recognize swing and stance phase is reachable. The theory used in this paper is useful for analyzing sEMG signal and actual prosthesis control.
Artificial Limbs ; Electromyography ; Humans ; Leg ; Muscle, Skeletal ; physiology ; Walking ; physiology

As an important auxiliary tool for amputees to gain abled limb functions, prosthetic limbs with decoration or feedforward control channel could not meet the needs. In order to enable the prosthesis to deliver the information, includes temperature, pressure, position, shape and so on, a variety of sensory feedback methods have been integrated into the prosthesis. According to the position of the feedback terminal on the human body, the perceptual feedback systems include invasive and noninvasive sensory feedback. This review presents the research progress of these perceptual feedback techniques, and summarizes the problems in the application in artificial limbs. Finally, the development trend of sensory feedback technology in prostheses is prospected.
Amputees ; Artificial Limbs ; Feedback, Sensory ; Humans ; Prosthesis Design ; Technology

Artificial prosthesis is an important tool to help amputees to gain or partially obtain abled human limb functions. Compared with traditional prosthesis which is only for decoration or merely has feedforward control channel, the perception and feedback function of prosthesis is an important guarantee for its normal use and self-safety. And this includes the information of position, force, texture, roughness, temperature and so on. This paper mainly summarizes the development and current status of artificial prostheses in the field of perception and feedback technology in recent years, which is derived from two aspects: the recognition way of perception signals and the feedback way of perception signals. Among the part of recognition way of perception signals, the current commonly adopted sensors related to perception information acquisition and their application status in prosthesis are overviewed. Additionally, from the aspects of force feedback stimulation, invasive/non-invasive electrical stimulation, and vibration stimulation, the feedback methods of perception signals are summarized and analyzed. Finally, some problems existing in the perception and feedback technology of artificial prosthesis are proposed, and their development trends are also prospected.
Amputees ; Artificial Limbs ; Feedback, Sensory ; Humans ; Prosthesis Design ; Prosthesis Implantation

Great importance and caution should be placed on prosthetic fitting for a paraplegic patient with an anesthetic residual limb if functional ambulation is to be achieved. The combination of paraplegia with a transfemoral amputation and radial nerve palsy is a complex injury that makes the rehabilitation process difficult. This article describes a case of L2 paraplegia with a transfemoral amputation and radial nerve palsy on the right side. Following the rehabilitation course, the patient independently walked using a walker at indoor level with a transfemoral prosthesis with ischial containment socket, polycentric knee assembly, endoskeletal shank and multiaxis foot assembly and a knee ankle foot orthosis on the sound side. The difficulties of fitting a functional prosthesis to an insensate limb and the rehabilitation stages leading to functional ambulation are reviewed.
Adult ; Amputation* ; Artificial Limbs* ; Case Report ; Femur/surgery* ; Human ; Male ; Paraplegia/rehabilitation* ; Radial Nerve*

Neuro signal has many more advantages than myoelectricity in providing information for prosthesis control, and can be an ideal source for developing new prosthesis. In this work, by implanting intrafascicular electrode clinically in the amputee's upper extremity, collective signals from fascicules of three main nerves (radial nerve, ulnar nerve and medium nerve) were successfully detected with sufficient fidelity and without infection. Initial analysis of features under different actions was performed and movement recognition of detected samples was attempted. Singular value decomposition features (SVD) extracted from wavelet coefficients were used as inputs for neural network classifier to predict amputee's movement intentions. The whole training rate was up to 80.94% and the test rate was 56.87% without over-training. This result gives inspiring prospect that collective signals from fascicules of the three main nerves are feasible sources for controlling prosthesis. Ways for improving accuracy in developing prosthesis controlled by neuro signals are discussed in the end.
Amputation ; Amputees ; Artificial Limbs ; Electrodes ; Humans ; Movement ; physiology ; Muscles ; innervation ; physiology ; Neurons ; physiology

In order to obtain the normal gait for the prosthesis-carrier with the change of external environment and gait, we designed a model of dynamic ankle prosthesis and control system and introduced the strategy of central pattern generator (CPG) about the moving trail of dynamic ankle prosthesis. The dynamic parts, which are incorporated in the model of dynamic ankle prosthesis, provide power in order to have anthropic function and character. The tool of Matlab/simulink was used to simulate the strategy. The simulation results showed that the strategy of CPG learn- ing control in this study was effective and could track the reference trail rapidly and fit the moving trail of a person's normal limb. It can make the prosthetic timely regulation and action, enhance the prosthetic intelligence. It has im- portant practical value for intelligent prosthesis development based on this analysis of technology.
Ankle Joint ; Artificial Limbs ; Biomechanical Phenomena ; Central Pattern Generators ; Gait ; Humans ; Joint Prosthesis

Proper signal sources for prosthetic limb control are the premises in designing upper extremities with high effectiveness and multi-degree of freedom(DOF). With an overview of input sources adopted in prosthetic design, this paper reviews comprehensively on characters of signals available for arm control.
Artificial Limbs ; Biomedical Engineering ; Electronics, Medical ; Electrophysiology ; Humans ; Prosthesis Design ; methods

A quantitative understanding of interface pressure distribution between prosthetic socket and residual limb is fundamental for an optimal design of prosthesis. Most of traditional finite element (FE) models were static. In this paper a 3-D nonlinear finite element model was developed according to the data of one transtibial amputee. The interface pressures at residual limb were predicted, and the effect of inertial loads was investigated quantitatively. The results show that interface pressures were mainly distributed at patella tendon, lateral tibia, media tibia and popliteal depression regions. Interface pressure had the similar double-peaked waveform in stance phase. The average difference in interface pressure between the two cases with and without consideration of inertial loads was 8.4% in stance phase, while it was up to 20.1% in swing phase with considerably different change trend. It is found that inertial effects during walking can not be ignored.
Artificial Limbs ; Finite Element Analysis ; Humans ; Leg ; Models, Theoretical ; Pressure ; Stress, Mechanical ; Tibia ; Walking

Monolimb is a new type of lower-limb prostheses made of macromolecule polymer, in which the socket and prosthetic shank are integrative. Compared with traditional prosthesis, monolimb is more economical, good-looking and portable, so it indicates a possible direction in the future. Biomechanical research on trans-tibial monolimb is necessary and helpful just like traditional prosthesis. In this article, a 3D FE model based on real geometry shape of an endoskeletal trans-tibial monolimb is established. Keeping the same geometrical shape, three 3D FE models of transtibial monolimbs with different wall thickness are established. The influence of wall thickness on the stress distribution is analyzed under the load corresponding to the subphase of stance of Heel Off. The results indicate that stress within transtibial monolimb and pressure on the surface of soft tissue could be decreased with wall thickness of transtibial monolimb increased. This study will be helpful for the standard of wall thickness in designing transtibial monolimb.
Amputees ; rehabilitation ; Artificial Limbs ; Biomechanical Phenomena ; Humans ; Leg ; surgery ; Prosthesis Design ; Stress, Mechanical