Prosthesis System Research Articles

The Utility of Synthetic Reflexes and Haptic Feedback for Upper-Limb Prostheses in a Dexterous Task Without Direct Vision.

Individuals who use myoelectric upper-limb prostheses often rely heavily on vision to complete their daily activities. They thus struggle in situations where vision is overloaded, such as multitasking, or unavailable, such as poor lighting conditions. Able-bodied individuals can easily accomplish such tasks due to tactile reflexes and haptic sensation guiding their upper-limb motor coordination. Based on these principles, we developed and tested two novel prosthesis systems that incorporate autonomous controllers and provide the user with touch-location feedback through either vibration or distributed pressure. These capabilities were made possible by installing a custom contact-location sensor on the fingers of a commercial prosthetic hand, along with a custom pressure sensor on the thumb. We compared the performance of the two systems against a standard myoelectric prosthesis and a myoelectric prosthesis with only autonomous controllers in a difficult reach-to-pick-and-place task conducted without direct vision. Results from 40 able-bodied participants in this between-subjects study indicated that vibrotactile feedback combined with synthetic reflexes proved significantly more advantageous than the standard prosthesis in several of the task milestones. In addition, vibrotactile feedback and synthetic reflexes improved grasp placement compared to only synthetic reflexes or pressure feedback combined with synthetic reflexes. These results indicate that autonomous controllers and haptic feedback together facilitate success in dexterous tasks without vision, and that the type of haptic display matters.

A biomimetic ocular prosthesis system: emulating autonomic pupil and corneal reflections

The human light modulation response allows humans to perceive objects clearly by receiving the appropriate amount of light from the environment. This paper proposes a biomimetic ocular prosthesis system that mimics the human light modulation response capable of pupil and corneal reflections. First, photoinduced synaptic properties of the quantum dot embedded photonic synapse and its biosimilar signal transmission is confirmed. Subsequently, the pupillary light reflex is emulated by incorporating the quantum dot embedded photonic synapse, electrochromic device, and CMOS components. Moreover, a solenoid-based eyelid is connected to the pupillary light reflex system to emulate the corneal reflex. The proposed ocular prosthesis system represents a platform for biomimetic prosthesis that can accommodate an appropriate amount of stimulus by self-regulating the intensity of external stimuli.

The first-generation anatomical medial meniscus prosthesis led to unsatisfactory results: a first-in-human study

PurposeThe purpose of this first-in-human study was to evaluate the effect of a polycarbonate anatomical meniscus prosthesis system, including the surgical procedure, on knee pain and describe potential adverse events in patients with post-meniscectomy pain syndrome.MethodsEleven patients with post-meniscectomy pain syndrome and limited underlying cartilage damage were enrolled in the study. Five received a medial polycarbonate urethane meniscus prosthesis which was clicked onto 2 titanium screws fixated at the native horn attachments on the tibia. The KOOS score was planned to be collected at baseline and at 3, 6, 12 and 24 months following the intervention including radiographs at 6, 12 and 24 months. MRI scans were repeated after 12 and 24 months.ResultsThe surgical technique to select an appropriately sized implant and correct positioning of the fixation screws and meniscus prosthesis onto the tibia was demonstrated to be feasible and reproducible. Inclusion stopped after 5 patients because of serious adverse device-related events. All patients reported knee joint stiffness and slight effusion in their knee at 6 months follow-up. In 3 patients the implant was removed because of implant failure and in 1 patient the implant was removed because of persistent pain and extension limitation. In none of the patients did the KOOS score improve in the first 6 months after surgery. However, in the patient who still has the implant in situ, PROMs started to improve 1 year after surgery and this improvement continued through 2 years of follow-up. The KOOS Pain, symptoms and ADL were close to the maximal 100 points. KOOS QoL and sport did improve but remained suboptimal.ConclusionThis first version of the meniscus prosthesis led to impaired knee function and failed in four out of five patients. The patients where the prosthesis was removed were salvable and the PROMs returned to pre-study levels. The results in the patient where the device is still in place are promising.Level of evidenceLevel II.

Electrically Small Circularly Polarized UWB Intraocular Antenna System for Retinal Prosthesis.

This paper presents the design of an electrically small circularly polarized (CP) 3 × 3 mm2 antenna system as an intraocular unit for retinal prosthesis application. The system is operating in ISM and ultra-wideband (UWB) bands to target high programmability of retina stimulation and recording, respectively. The electrical dimensions, including the ground plane, are λ0/41 × λ0/41 × λ0/191. Physical limitations of the antenna are discussed based on Hansen and Collin's limitations. The proposed wire patch antenna exhibits wideband characteristics by combining multiple modes of the patch antenna in the presence of an interface PCB circuit. By loading polyimide encapsulated patch with stubs, dominant TM010 mode is combined with the higher order modes TM020-TM070 to exhibit wide -10 dB impedance bandwidth of 2-11 GHz. Annular rings and shorting pins in the ground plane provide CP radiation at 2.45, 5.8, and 8 GHz with 3-dB axial-ratio bandwidth of 0.3, 0.16, and 1.2 GHz, and far-field left hand circularly polarized (LHCP) gain of -18.4, -7.6, and -4.7 dBic, respectively, in broadside direction. A biocompatible antenna system is designed using Ansys HFSS in the presence of a detailed multilayer canonical eye model. Additionally, it is examined in an anatomical HFSS head model. Near and far-field electric field distribution is studied along with peak 1-g average specific absorption rate (SAR) calculations. The proposed antenna is fabricated, and the performance, including coupled power from an external antenna, is measured in a custom made eye model including head phantom. A reasonable agreement is obtained between simulated and measured results. To generate an artificial vision, image perception capability could be improved with implantable UWB communication systems that feature particularly high data-rate and small size.

Twenty-four months of bacterial colonialization and infection rates in patients with transcutaneous osseointegrated prosthetic systems after lower limb amputation-A prospective analysis.

Transcutaneous osseointegrated prosthesis systems (TOPS) are alternative rehabilitation methods to socket prosthetics, after limb amputation. TOPS compromise a two-step surgery: starting with the implantation of the stem which is then followed by the creation of the transcutaneous stoma through which the exoprosthesis can be connected. Immediately after surgery, this opening is permanently exposed to pathogens. This study aimed to investigate the dynamics of bacterial colonization of the stoma to analyze whether obligate bacterial colonization leads to a risk of periprosthetic infections after TOPS treatment. This prospective study analyzed data from 66 patients (aged 26-75 years) after TOPS treatment between 2017 and 2019. Microbiological swabs from the stoma were analyzed on the first postoperative day and 3, 6, 12, and 24 months after stoma creation. Infection rates, laboratory values (CRP, leukocyte count, hemoglobin), and body temperature were recorded at these points in time. Statistical analysis was performed using SPSS 28. The results show the formation of a stable environment dominated by Gram-positive bacteria in the stoma of TOPS patients over 24 months. Staphylococcus aureus, Staphylococcus spp., and Streptococcus spp. were the most common species found. With regard to the cohort up to the 3 months follow-up, 7.9% (five patients) developed infections surrounding the TOPS procedure. In relation to the whole cohort with loss to follow-up of 80.3% at the 24 months follow-up the infection rates increased up to 38.3%. The soft tissue inside and around the transcutaneous stoma is colonialized by multiple taxa and changes over time. A stable Gram-positive dominated bacterial taxa could be a protective factor for ascending periprosthetic infections and could possibly explain the relatively low infection rate in this study as well as in literature.

Design and Implementation of a Prosthesis System Controlled by Electromyographic Signals Means, Characterized with Artificial Neural Networks.

Around the world many people loss a body member for many reasons, where advances of technology may be useful to help these people to improve the quality of their lives. Then, designing a technologically advanced prosthesis with natural movements is worthy for scientific, commercial, and social reasons. Thus, research of manufacturing, designing, and signal processing may lead up to a low-cost affordable prosthesis. This manuscript presents a low-cost design proposal for an electromyographic electronic system, which is characterized by a neural network based process. Moreover, a hand-type prosthesis is presented and controlled by using the processed electromyographic signals for a required particular use. For this purpose, the user performs several movements by using the healthy-hand to get some electromyographic signals. After that, the obtained signals are processed in a neural network based controller. Once an usable behavior is obtained, an exact replica of controlled motions are adapted for the other hand by using the designed prosthesis. The characterization process of bioelectrical signals was performed by training twenty characteristics obtained from the original raw signal in contrast with other papers in which seven characteristics have been tested on average. The proposed model reached a 95.2% computer test accuracy and 93% accuracy in a real environment experiment. The platform was tested via online and offline, where the best response was obtained in the online execution time.

Analysis of thin wall cells made of Zhermack silicone rubber used for lower limb prosthesis

The suspension system of the lower limb prosthesis has the main role of providing the permanent contact with the stump. The paper proposed the FEM analysis and the experimental study on the thin wall cells as part of a network inflated with dry air at very well controlled pressure values. The cells are made of bicomponent silicone rubber Zhermack that is biocompatible and has very good elastic properties. The theoretical aspect of this study by using FEM method has computed acceptable values for the Von Misses stress and for the deformation, so that the pressure over the tissue is inside the recommended limits. The designed experimental set-up provides the values for pressure force needed to keep the permanent contact over the entire external surface of the thin wall cell.

Light–controlled hydrogel platform for high-resolution chemical stimulation

Localized chemical delivery plays an essential role in the fundamental information transfers within biological systems. Thus, the ability to mimic the natural chemical signal modulation would provide significant contributions to understand the functional signaling pathway of biological cells and develop new prosthetic devices for neurological disorders. In this paper, we demonstrate a light-controlled hydrogel platform that can be used for localized chemical delivery in a high spatial resolution. By utilizing the photothermal behavior of graphene-hydrogel composites confined within micron-sized fluidic channels, patterned light illumination creates the parallel and independent actuation of chemical release in a group of fluidic ports. The new platform promises the feasibility of creating a novel synaptic interface with large arrayed chemical stimulation capability toward biochemically controlled neural prosthesis systems.

Knee Bending Prevention System for Robotic Knee Prosthesis Using Finite State Machine

Knee Bending Prevention System for Robotic Knee Prosthesis Using Finite State Machine

Ambulation Control System Design for a Hybrid Knee Prosthesis.

Prosthetic knees available to individuals with transfemoral amputation seek to restore functional ability to the user. Passive prosthetic knees are lightweight but can restore only limited, dissipative ambulation activities whereas active knees can provide energy to restore additional ambulation activities such as stair climbing and standing up from a chair. Semi-active prosthetic devices aim to only power a subset of activities and use passive components and control when that power is not necessary. Here, we outline an ambulation control system for a lightweight Hybrid Knee prosthesis that is powered for climbing stairs and passive for other ambulation activities (level-ground walking, walking on an incline, and stair descent). We include preliminary offline and online intent recognition system results for one able-bodied user and one individual with a transfemoral amputation demonstrating low error rates in predicting between active and passive control.

Pre-clinical evaluation of fretting-corrosion at stem-head and stem-cement interfaces of hip implants using in vitro and in silico models.

Prior to clinical use, the corrosion resistance of new prosthesis system must be verified. The fretting-corrosion mechanisms of total hip arthroplasty (THA) implants generate metal debris and ions that can increase the incidence of adverse tissue reactions. For cemented stems, there are at least two interfaces that can be damaged by fretting-corrosion: stem-head and stem-cement. This investigation aimed to evaluate, through in vitro and in silico analyses, fretting-corrosion at the stem-head and stem-cement interfaces, to determine which surface is most affected in pre-clinical testing and identify the causes associated with the observed behavior. Unimodular stems and femoral heads of three different groups were evaluated, defined according to the head/stem material as group I (SS/SS), group II (CoCr/SS), and group III (CoCr/CoCr). Seven pairs of stems and heads per group were tested: three pairs were subjected to material characterization, three pairs to in vitro fretting-corrosion testing, and one pair to geometric modeling in the in silico analysis. The absolute area of the stem body degraded was more than three times higher compared with the trunnion, for all groups. These results were corroborated by the in silico analysis results, which revealed that the average micromotion at the stem-cement interface (9.65-15.66 μm) was higher than that at the stem-head interface (0.55-1.08 μm). In conclusion, the degradation of the stem-cement interface is predominant in the pre-clinical set, indicating the need to consider the fretting-corrosion at the stem-cement interface during pre-clinical implant evaluations.

A narrative review of cortical visual prosthesis systems: the latest progress and significance of nanotechnology for the future.

Background and ObjectiveWe sought to review the latest developments in cortical visual prosthesis (CVP) systems and the significance of nanotechnology for the future. Over the past century, CVP systems have been researched and developed, resulting in various unique surgical and mechanical techniques. Research findings indicate that partial vision recovery is possible, with improvements in coarse target functions and performance in routine activities.MethodsThis review discusses the architecture and physiology of the visual cortex, the neuroplasticity of the blind brain, and the history of CVP development, and also provides an update on the CVP systems currently being examined in research and clinical trials. Due to advances in nanotechnology, it is possible to make CVPs that are smaller, more efficient, and more biocompatible than ever before.Key Content and FindingsCurrently, 3 CVPs have entered clinical trials, and several additional systems are undergoing preclinical reviews to determine the safety of the devices for chronic implantation. This development provides the first indication that the area of cortical vision restoration medication may be able to meaningfully benefit blind people. However, several significant technical and biological challenges need to be solved before the gap between artificial and natural eyesight can be reconciled. Rapid breakthroughs in nanotechnology have considerably increased its use in biological domains.ConclusionsThis paper summarizes the recent progress of CVP in recent years and its future development direction. It is forecasted that nanotechnology can provide better technical support for the development of CVP.

Morphology characters of resected femoral and tibial surface in chinese population: intraoperative anthropometric study in patients at a tertiary hospital

BackgroundsMismatch between knee surface and prosthesis components is related to postoperative complications. Morphological differences between ethnicity and gender may affect prosthesis coverage. The purpose of this study is to describe morphological characters of resected knee surface (distal femur, proximal tibia) in the Chinese population, analyze the influence of gender and other demographical factors, and validate the effect of ethnic difference by calculating the coverage of Western-designed knee prostheses on Chinese knee surface.MethodsIntraoperative anthropometries were performed during total knee arthroplasty performed by one single team. After screening out severe deformities and bone defects, data were separated via prosthesis system. Multiple linear regression and partial correlation analysis of morphological parameters on age, gender, height, weight were used to find out independent factors influencing morphology. Based on the 5 mm-tolerance in the prosthesis, simulation on scatter plots was brought out to calculate the prosthesis coverage to the resected bone surface.ResultsA total of 865 cases of total knee arthroplasty were involved in this study. Though gender differences were found in all knee morphological parameters regardless of the type of prosthesis, significant association was only found between gender and mediolateral width of femoral surface after adjusting demographical factors (p < 0.001). The two included prosthesis systems, Genesis-II and Scorpio NRG covered most cases in at least one dimension. Males had lower complete coverage and higher no coverage rate on femurs. Asymmetry prostheses had higher lateral coverage on tibiae.ConclusionsBased on our analysis, the only confirmed demographical factor in knee morphology is gender on femoral mediolateral length. Wider femoral prostheses for males may improve results of gender-specific prostheses. The overall fitness between Western-designed prostheses and Chinese knee surface is appliable, but the ratio of complete coverage is low. Further modification of prostheses systems can aim at the number of sizes and geometrical shapes.

Robust and compliance control for robotic knee prosthesis using admittance model and sliding-mode controller

Achieving compliance and flexibility under the premise of ensuring trajectory tracking performance and also reflecting the wearer’s movement intention, has not yet been well solved in the field of prosthesis. The aim of this paper is to provide a compliant, robust, and continuous control scheme for robotic knee prosthesis to solve the contradictory problems of trajectory tracking performance and compliance. The proposed scheme are based on the admittance model and radial basis function (RBF) neural network–enhanced nonsingular fast terminal sliding-mode controller (NFTSMC). The desired trajectory of the prosthetic knee joint is driven by humans and reshaped to reference trajectory by an admittance model, so that the prosthetic leg can reflect the human’s movement intention and being compliant. RBF neural network is introduced to achieve adaptive approximation of unknown models and ensure that the controller does not depend on the mathematical model of the “human-in-the-loop” prosthesis system. A novel NFTSMC was proposed to deal with the influence of ground reaction forces (GRFs) and fitting errors of the RBF neural network, which make the tracking error converge to zero in a finite time. The adaptive law of the RBF neural network is obtained by the Lyapunov method, and the stability and finite-time convergence of the closed-loop system are rigorously proved and analyzed mathematically. The simulation results prove the feasibility and effectiveness of the propose control scheme.

Two-Way Communication Digital Power Controllers for Wireless Retinal Prosthesis Systems.

Power-efficient digital controllers are proposed for wireless retinal prosthetic systems. Power management plays an important role in reducing the power consumption and avoiding malfunctions in implantable medical devices. In the case of implantable devices with only one-way communication, the received power level is uncertain because there is no feedback on the power status. Accordingly, system breakdown due to inefficient power management should be avoided to prevent harm to patients. In this study, digital power controllers were developed for achieving two-way communication. Three controllers—a forward and back telemetry control unit, a power control unit, and a preamble control unit—operated simultaneously to control the class-E amplifier input power, provided command data to stimulators, monitored the power levels of the implanted devices, and generated back telemetry data. For performance verification, we implemented a digital power control system using a field-programmable gate array and then demonstrated it by employing a wireless telemetry system.

Inverted-bearing reverse total shoulder arthroplasty: scapular notching does not affect clinical outcomes and complications at up to 7 years of follow-up.

Scapular notching is a common complication of reverse total shoulder arthroplasty (RTSA). Inverted-bearing RTSA (IB-RTSA) systems, with polyethylene (PE) glenospheres and metal or ceramic humeral liners, reduce notching and PE wear compared with traditional Grammont prosthesis designs. However, whether notching after IB-RTSA influences clinical outcomes or complications remains unknown. Therefore, we evaluated the influence of notching on midterm clinical outcomes and complication rates after IB-RTSA. In our prospective multicenter, observational study, patients underwent IB-RTSA, using a prosthesis system with a PE glenosphere and a metal humeral component. We assessed patients clinically for functional scores, active range of motion, and pain and radiographically for notching. Overall, 270 patients (284 shoulders) were treated with IB-RTSA. Of these, 229 shoulders were available for a mean follow-up of 86.7 months (range, 24.0-133.4 months). We observed notching in 35% of shoulders (28% grade 1; 3% grade 2; and 4% grade 3). IB-RTSA led to a distinct type of notching representing the mechanical indent of the humeral component into the scapular neck without PE-induced osteolysis. Patients with and without notching showed similar clinical outcomes (P ≥ .05), complication rates (P = .23), revision rates (P = .87), and survival of implant components after 10 years (P = .85). Midterm results confirmed our hypothesis that patients with notching had equally good clinical outcomes and low complication rates as patients without notching. Additionally, we found a distinct type of notching without signs of PE-induced osteolysis.

Adaptive Control System of Intelligent Lower Limb Prosthesis Based on 5G Virtual Reality

With the rapid development of computer science and technology in our country, especially the advent of the 5G network era, the emergence of smart prostheses makes it possible for disabled, injured, or amputee people with lower limbs to walk and exercise like normal people. However, due to the different selection of prosthetic materials, the final lower limb prostheses produced will also have different performance differences. How to select prosthetic materials to optimize the performance of the intelligent lower limb prosthesis is the focus of extensive discussion in the medical community. For this reason, this article takes the research of the adaptive control system of intelligent lower limb prosthesis based on 5G virtual reality as the research object. By using the current advanced 5G communication technology and virtual reality technology, a high-performance intelligent lower limb prosthesis is produced. Provide assistance with basic walking and motor abilities in daily life of patients with lower limb disabilities. This article first gives a systematic theoretical introduction to 5G virtual reality technology, expounds the current status of patients with lower limb disabilities, and proposes to use intelligent lower limb prosthetics to replace healthy lower limbs to solve the basic walking and sports needs of disabled patients in daily life and then use 5G virtual reality technology. The selection of human knee joints and ankle joints and structural system design were carried out. Finally, it was decided to use the four-bar linkage structure as the knee joint structure of the three-dimensional modeling of the intelligent lower limb prosthesis. At the end of this article, the application and simulation of the intelligent lower limb prosthesis to the human body were also carried out. The results of the experiment found that after 45 weeks of wearing exercises, the gait of the intelligent lower limb prosthesis is consistent with the expected effect whether it is walking on level ground and up and down the stairs or uphill. Due to the strong adaptiveness of the intelligent lower limb prosthesis sexual control, it can well assist the basic life movement ability of patients with lower limb disabilities.

Adjustable suspension system for lower limb prosthesis

The contact between the stump and the lower limb prosthesis has to be provided by its suspension system. The paper presents a solution for an adjustable suspension designed as an inflated cell network. Each cell is supplied with controlled pressure and consequently, a contact force with the skin is developed. By varying the pressure value inside the cell, we may provide variable force, so the compensation for the volume change of the stump could be accomplished. The material the cells are made of should have special properties, the elasticity being the most important. Moreover, the goal of the paper was to approve the opportunity to use the silicone rubber Zhermack for the cell material and a mechatronic system has been realised as experimental set-up.

Knee disarticulation following oncologic total knee arthroplasty: A 5-year follow-up case report

BackgroundThe present case report describes the 5-year follow-up results of an atypical knee disarticulation of a man previously treated with an oncologic total knee arthroplasty due to an Ewing sarcoma. MethodsThe patient presented an aseptic loosened tibial component of a tumor prosthesis system and requested final amputation, as he had previously suffered from five revision surgeries. To encourage the most functional outcome regarding an exoskeletal prosthesis, we decided to disarticulate the knee joint while retaining the currently fixed femoral component to create a full end-bearing stump. FindingsThe patient could be mobilized as a functional knee disarticulated amputee. Seven months after amputation, he showed a slightly less symmetrical gait compared to the preoperative status (preoperative mean Symmetry Index: 0.984 for kinematics and 0.940 for kinetics, 7-month postoperative Symmetry Index: 0.858 and 0.915). At the 5-year follow-up, the femoral component is still stably fixated and shows no loosening signs. In addition, the Symmetry Index increased to 0.908 and 0.949. InterpretationEven after 5 years, the presented amputation appears to be consistent with “conventional” knee disarticulation. The femoral component still withstands the altered loads and the patient shows a further improved gait pattern.

Visual Rehabilitation After Retinal Prosthesis Implantation: An 18-month Case Report, From Candidate Selection to Follow-Up

Introduction: Various retinal implants are being developed and appear to be a promising option for improving the visual capacities of individuals with retinal dystrophy. A multidisciplinary approach to both assessment of a candidate’s factors and rehabilitation could contribute to improved activity and participation. The purpose of this study was (i) to document the approach taken by a multidisciplinary team in the candidate selection process and in training in the use of the Argus II retinal prosthesis system (RPS), and (ii) to examine the effects of the RPS on sensory and mental functions and on activity and participation. Methods: An A1-B1-A2-B2 experimental case report was used, with repeated measures pre- and post-rehabilitation program design. The A phases represent the periods with the system off, whereas the B phases represent the periods with the system on. A 65-year-old man with retinitis pigmentosa and total blindness was followed by a multidisciplinary team for over 18 months. After receiving the retinal implant, he benefited from a 10-week rehabilitation program (twice per week; B1 phase). Results: Globally, the RPS improved vision in the B phases when the system was on and visual acuity was stable at 2.3 logMAR (functional blindness). The participant’s mental and neuromusculoskeletal function scores were generally stable throughout the data collection periods. Lower performance on some measures at the end of phase B2 coincided with a negative mood. Discussion: Use of the RPS improved activity, but this did not transfer into greater participation in the living environment. Despite efforts made by the rehabilitation team to manage the user’s expectations concerning the RPS, the interventions reactivated his grieving over his vision loss. Implications for Practitioners: New technologies can make users dream of unrealistic possibilities, and managing their expectations requires problem solving supported by a multidisciplinary team.