Prosthetic Engineering Research Articles

Analysis on Characteristics of Implants and Surface Bionic Prosthetic Materials

According to the 19902020 Internet for literature on materials commonly used in prosthetics and their compatibility with skin tribology and biology, it found that with the large number of amputees affected by the disease, traffic accidents, work-related injuries, and natural disasters, the relatively high manufacturing costs of prostheses could place a financial burden on patients. In addition, the choice of prosthetic material itself affects the comfort and ease of use for the patient. Whether it is an osseointegrated prosthesis or a cavity-receiving prosthesis, the use of appropriate materials is an important issue in prosthetic engineering. This paper analyses the research conducted over the last 20 years on materials for implantable prostheses and receptive cavity materials and presents some of the findings on the preferred material selection for each type of material, as well as the associated biomechanical effects and skin tribology. Through the analysis, the paper concludes that for implantable materials, biocompatible materials such as metallic materials, bioceramics, and composites are preferred. For receptive cavity materials, polymeric materials such as thermoplastic sheets, resin-based composites, and low-temperature thermoplastics are preferred.

Dynamics of indicators of vestibular dysfunction and walking locomotion in men aged 25-42 years with the consequences of a combat wound as a result of the influence of physical culture and sports rehabilitation

The purpose of the study was to investigate and evaluate the dynamics of basometry and stabilometry in men aged 25-42 with the consequences of a combat injury.
 Material & Methods: examined 38 men aged 25-42 years with long-term consequences of closed craniocerebral injury in the late long-term period, which were divided into Gr1 (n=20) and Gr2 (n=18). Vestibular dysfunction, mobility was determined by the Bohannon and "TUG" tests. To determine the biomechanical characteristics of walking, a hardware-software basometric complex and methods of the Ukrainian Research Institute for Prosthetics, Prosthetic Engineering and Recovery were used.
 Results: when developing a correctional and rehabilitation program, thanks to the concept of the ICF, Smart goals were set. At stage 1 of inpatient rehabilitation (28 days), the program is composed of components. For men in both groups, the normative component was the same. Kinesitherapy, classes on the C-mill system, on the «Cosmos» treadmill, and massage were prescribed. Persons Gr1 in the variable part were trained on the Redcord suspension system, Nordic walking and vestibular gymnastics. The men of Gr2 were prescribed a general training on a multifunctional block simulator, training walking. At the 2nd stage (42 days) the persons of both groups were exercising independently, however, the persons of Gr1, with the help of modern telecommunication technologies, were exercising under the supervision of a specialist in physical rehabilitation. The dynamics of the balance indicator according to the Bohann test indicated that the persons Gr1 balance indicator almost approached the normative value. In Gr2 positive changes were observed, however, after stage 2 the difference was only 0.44 points compared with the dynamics of stage 1 (p>0,05). The dynamics of functional mobility and balance according to the "TUG" test indicated that the average time to complete the test after stage 2 approached the standard value. In patients, Gr2 tended to decrease (p>0,05). Biomechanical studies of statics, namely the coefficient of resistance, rotation of pressure centers, the common center of pressure in the frontal and sagittal plane in men Gr1 acquired significant differences (p<0,05); in men Gr2 tended to improve (p>0,05). The main indicators of walking locomotion, namely the pace and speed in men Gr1 and Gr2, acquired a standard value (p<0,05). The walking rhythm coefficient and load asymmetry index in men Gr2 did not acquire the normative value (p>0,05), in comparison with the indices of men Gr1 (p<0,05), who were engaged under the supervision of a specialist in physical culture and sports rehabilitation.
 Conclusions: the results of the study revealed a violation of walking in men aged 25-42 years with the consequences of a combat injury in the form of temporal, kinematic and dynamic asymmetry. The analysis of the dynamics of the parameters of vestibular dysfunction and walking locomotion confirmed the advantages of the author's program.

UStEMG: an Ultrasound Transparent Tattoo-based sEMG System for Unobtrusive Parallel Acquisitions of Muscle Electro-mechanics.

Human machine interfaces follow machine learning approaches to interpret muscles states, mainly from electrical signals. These signals are easy to collect with tiny devices, on tight power budgets, interfaced closely to the human skin. However, natural movement behavior is not only determined by muscle activation, but it depends on an orchestration of several subsystems, including the instantaneous length of muscle fibers, typically inspected by means of ultrasound (US) imaging systems. This work shows for the first time an ultra-lightweight (7 g) electromyography (sEMG) system transparent to ultrasound, which enables the simultaneous acquisition of sEMG and US signals from the same location. The system is based on ultrathin and skin-conformable temporary tattoo electrodes (TTE) made of printed conducting polymer, connected to a tiny, parallel-ultra-low power acquisition platform (BioWolf). US phantom images recorded with the TTE had mean axial and lateral resolutions of 0.90±0.02 mm and 1.058±0.005 mm, respectively. The root mean squares for sEMG signals recorded with the US during biceps contractions were at 57±10 µV and mean frequencies were at 92±1 Hz. We show that neither ultrasound images nor electromyographic signals are significantly altered during parallel and synchronized operation.Clinical relevance- Modern prosthetic engineering concepts use interfaces connected to muscles or nerves and employ machine learning models to infer on natural movement behavior of amputated limbs. However, relying only on a single data source (e.g., electromyography) reduces the quality of a fine-grained motor control. To address this limitation, we propose a new and unobtrusive device capable of capturing the electrical and mechanical behavior of muscles in a parallel and synchronized fashion. This device can support the development of new prosthetic control and design concepts, further supporting clinical movement science in the configuration of better simulation models.

Quasi-stiffness of the knee joint is influenced by walking on a destabilising terrain

BackgroundPredictive models have been devised to estimate the necessary quasi-stiffness that a transfemoral prosthesis should be set to aligning the body and gait parameters of the user. Current recommendations exist only for walking over level ground. This study aimed to ascertain whether walking across destabilising terrain influences the quasi-stiffness of the knee joint thus influencing prosthetic engineering. MethodsTen healthy males (age: 25.1 ± 2.5 years; mean ± sd, height: 1.78 ± 0.05 m, weight: 84.40 ± 11.02 kg) performed 14 gait trials. Seven trials were conducted over even ground and seven over 20 mm ballast. Three-dimensional motion capture and ground reaction force were collected. Paired samples t-tests and Wilcoxon signed ranked test compared variables including; quasi-stiffness, gait speed, stride length and stride width. ResultsQuasi-stiffness (d = 0.562, P = 0.001) and stride width (d = 0.909, P < 0.001) were significantly greater in the destabilising terrain condition. Gait speed (r = −0.731, P = 0.001) was significantly greater in the control condition. No significant difference was seen in stride length (d = 0.583, P = 0.016). ConclusionsAn increase in quasi-stiffness when walking across destabilising terrain was attributed to a magnified shock absorption mechanism, facilitating an increased flexion angle during the stance phase. This causes a lower centre of mass resulting in the musculoskeletal system having to produce a greater knee extensor moment to prevent the knee collapsing. Therefore, transfemoral prostheses should be tuned to apply increased extension moments if ambulation is to occur on a destabilising terrain.

Mechanical energy profiles of the combined ankle–foot system in normal gait: Insights for prosthetic designs

Over the last half-century, the field of prosthetic engineering has continuously evolved with much attention being dedicated to restoring the mechanical energy properties of ankle joint musculatures during gait. However, the contributions of ‘distal foot structures’ (e.g., foot muscles, plantar soft tissue) have been overlooked. Therefore, the purpose of this study was to quantify the total mechanical energy profiles (e.g., power, work, and work-ratio) of the natural ankle–foot system (NAFS) by combining the contributions of the ankle joint and all distal foot structures during stance in level-ground steady state walking across various speeds (0.4, 0.6, 0.8 and 1.0statures/s). The results from eleven healthy subjects walking barefoot indicated ankle joint and distal foot structures generally performed opposing roles: the ankle joint performed net positive work that systematically increased its energy generation with faster walking speeds, while the distal foot performed net negative work that systematically increased its energy absorption with faster walking speeds. Accounting for these simultaneous effects, the combined ankle–foot system exhibited increased work-ratios with faster walking. Most notably, the work-ratio was not significantly greater than 1.0 during the normal walking speed of 0.8statures/s. Therefore, a prosthetic design that strategically exploits passive-dynamic properties (e.g., elastic energy storage and return) has the potential to replicate the mechanical energy profiles of the NAFS during level-ground steady-state walking.

Prosthetic rehabilitation of the upper limb amputee

ABSTRACTThe loss of all or part of the arm is a catastrophic event for a patient and a significant challenge to rehabilitation professionals and prosthetic engineers. The large, upper extremity amputee population in India has, historically, been poorly served, with most having no access to support or being provided with ineffective prostheses. In recent years, the arrival of organisations like Otto Bock has made high quality service standards and devices accessible to more amputees. This review attempts to provide surgeons and other medical professionals with an overview of the multidisciplinary, multistage rehabilitation process and the solution options available. With worldwide upper extremity prosthesis rejection rates at significant levels, the review also describes some of the factors which influence the outcome. This is particularly relevant in the Indian context where the service can involve high cost investments. It is the responsibility of all contributing professionals to guide vulnerable patients through the process and try to maximise the benefit that can be obtained within the resources available.

Prosthetic rehabilitation of the upper limb amputee

The loss of all or part of the arm is a catastrophic event for a patient and a significant challenge to rehabilitation professionals and prosthetic engineers. The large, upper extremity amputee population in India has, historically, been poorly served, with most having no access to support or being provided with ineffective prostheses. In recent years, the arrival of organisations like Otto Bock has made high quality service standards and devices accessible to more amputees. This review attempts to provide surgeons and other medical professionals with an overview of the multidisciplinary, multistage rehabilitation process and the solution options available. With worldwide upper extremity prosthesis rejection rates at significant levels, the review also describes some of the factors which influence the outcome. This is particularly relevant in the Indian context where the service can involve high cost investments. It is the responsibility of all contributing professionals to guide vulnerable patients through the process and try to maximise the benefit that can be obtained within the resources available.

Clinical Applications of Intraspinal Microstimulation

Intraspinal microstimulation is a neuroprosthetic approach for activating specific spinal reflexes using penetrating electrodes chronically implanted into spinal cord. Artificial control of spinally mediated functions, such as arm and leg movement or bladder voiding, may be necessary in spinal cord injury, multiple sclerosis, cerebral palsy, amyotrophic lateral sclerosis, and spina bifida, when the brain becomes disconnected from spinal cord and a person loses control over these functions. Animal studies indicate the feasibility of efficient control of bladder voiding and limb movement. Development of novel microstimulation electrodes focuses on reduction of electrode dimensions for improved targeting efficiency, decreased tissue trauma, improved biocompatibility, and long-term safety and reliability of applied stimulation. Clinical usefulness of existing devices is limited by a lack of highly integrated and biocompatible neuroprosthetic systems, comprising high-density electrode arrays and integrated electronics for pulse generation and stimulation site addressing. Future developments will require a coordinated effort in the areas of neural prosthetic engineering, applied neurophysiology, neurosurgery, physical therapy, and rehabilitation. In the long term, clinical applications of intraspinal microstimulation may include treatments of such spinal cord-related disabilities, such as bladder and bowel emptying, sexual function, hand and arm control, and even walking. These treatments can address the long-standing needs of paralyzed patients aimed at improving their medical, psychological, social, and work-related conditions.