Electromyographically controlled prosthetic wrist improves dexterity and reduces compensatory movements without added cognitive load.

Wrist function is a top priority for transradial amputees. However, the combined functional, biomechanical, and cognitive impact of using a powered prosthetic wrist is unclear. Here, we quantify task performance, compensatory movements, and cognitive load while three transradial amputees performed a modified Clothespin Relocation Task using two myoelectric prostheses with and without the wrists. The two myoelectric prostheses include a commercial prosthesis with a built-in powered wrist, and a newly developed inexpensive prosthetic wrist for research purposes, called the "Utah wrist", that can be adapted to work with various sockets and prostheses. For these three participants, task failure rate decreased significantly from 66% ± 12% without the wrist to 39% ± 9% with the Utah wrist. Compensatory forward leaning movements also decreased significantly, from 24.2° ± 2.5 without the wrist to 12.6° ± 1.0 with the Utah wrist, and from 23.6° ± 7.6 to 15.3° ± 7.2 with the commercial prosthesis with an integrated wrist. Compensatory leftward bending movements also significantly decreased, from 20.8° ± 8.6 to 12.3° ± 5.3, for the commercial with an integrated wrist. Importantly, simultaneous myoelectric control of either prosthetic wrist had no significant impact on cognitive load, as assessed by the NASA Task Load Index survey and a secondary detection response task. This work suggests that functional prosthetic wrists can improve dexterity and reduce compensation without significantly increasing cognitive effort. These results, and the introduction of a new inexpensive prosthetic wrist for research purposes, can aid future research and development and guide the prescription of upper-limb prostheses.

Femoral fracture in an amputation stump.

Presentation: We report a case of a 60-year-old male with bilateral lower limb amputations who sustained a fracture to his right residual femur after weight bearing on his prosthetic leg during therapy. This was attributed to his raised body mass index that fell in the morbidly obese category. Diagnosis: Patient was referred for orthopaedic management and reviewed by the multidisciplinary prosthetic rehabilitation team following the fracture recovery. Treatment: He was deemed unsuitable for further prosthetic usage and ultimately referred to the national weight management service and the bariatric team. Discussion: Fracture of the residual limb in an amputee is not a common occurrence. There is a scarcity of information regarding fractures in an amputation stump of obese individuals. This is an unusual case which highlights the significance of body weight on lower limb prosthetic usage, impact on rehabilitation and the need to address weight management at an earlier stage post amputations.

3D-printed orthoses and prostheses for people with physical disability in rehabilitation centers: a scoping review.

AIMS: The World Health Organization points out that, by 2030, two billion people will need at least one assistive product. 3D printing can be used to meet the demands when dispensing these products. PURPOSE: This review aims to map the use of 3D printing in the manufacture of orthoses and prostheses for people with physical disability at rehabilitation centers. METHODS: Publications that deal with the use of 3D printing for the manufacture of orthoses and prostheses were used, preferably studies from 2012 to 2022. RESULTS: The majority of studies, 56.25%, were quantitative and 46.25% were evaluative research. None of the studies were characterized as developed at rehabilitation centers. 75% of them had the participation of people with physical disability. The use of 3D printing was, for the most part, for the development of assistive technologies for the upper limbs at 56.25%, while 31.25% were for the lower limbs. CONCLUSION: The assistive products developed were orthoses and prostheses for the wrist, hands, fingers, upper limbs, writing devices, sockets, knees, and feet. Although there were positive results in their performance, some limitations related to strength, stiffness, and resistance were observed.

Epidemiology and Impact of Limb Loss in the United States and Globally.

The main causes of limb loss include trauma, complications from diabetes and peripheral arterial disease, malignancy, and congenital limb deficiency. There are significant geographic variations in the incidence of upper and lower, and major and minor limb loss worldwide. Limb loss is costly for patients and the health care system. The availability of orthotic and prosthetic services, along with cost of services, represents barrier to care and contributes to morbidity and mortality. More research is needed, especially in low-income and middle-income countries to describe the extent of limb loss.

Amputation Surgery: Review of New and Emerging Techniques.

Major upper and lower extremity amputations are increasingly being performed for peripheral vascular disease, infectious etiologies, trauma, and oncologic purposes. Attention to technique and emerging treatments for the residual peripheral nerve is critical to prosthetic wear and quality of life following these life changing events. Here, we detail advancements in amputation surgery including targeted muscle reinnervation, regenerative peripheral nerve interface, and the use of osseointegrated implants.

Adaptive Sports and Recreation in Persons with Limb Loss/Limb Deficiency.

Adaptive sports are a vital component in the continuum of rehabilitation for people with limb loss/limb deficiency (LL/LD), across the lifespan. Identifying the barriers and understanding health care disparities inform ways to help people with LL/LD stay active and reach their health and wellness goals. Building knowledge in adaptive sports helps facilitate having a person go beyond activities of daily living and basic locomotion. Considering the participant, requirements of the sport, and the activity-specific prosthesis/equipment required leads to successful participation in adaptive sports.

Dermatologic Conditions Following Limb Loss.

The use of prostheses in individuals with limb loss increases the risk of maceration, friction, and pressure-induced skin injuries due to the vulnerability of the residual limb and the close contact with the socket. Poorly fitting prostheses exacerbate these issues, especially for those with immunosuppression or vascular conditions. Skin pathologies disrupt daily prosthetic limb use and impact the independence of those with limb loss. Preventive measures, including proper prosthesis socket fitting and meticulous skin care, are crucial. This review explores residual limb-site skin pathologies and details current mitigation and management strategies.

Prosthetic Componentry in Lower Limb Prosthetic Restoration.

This article describes fundamental lower limb prosthesis concepts and componentry, including skeletal structure (endoskeletal vs exoskeletal), transtibial and transfemoral sockets, prosthetic suspension and interfaces, prosthetic knees, and prosthetic foot and ankle systems.

Prostheses and Rehabilitation Principles in Pediatric Limb Deficiency.

Pediatric limb loss or limb deficiency is uncommon in the United Sates occurring 1 per 1943 live births per year, with a ratio of 2:1 upper to lower extremity.1 Causes include congenital limb deficiency, and less frequently, limb loss secondary to trauma, cancer, or other illnesses. Vascular disruption, particularly as seen in amniotic band syndrome, stands as the leading suspect in the multifaceted and intricate causes of congenital limb loss. Children with limb difference and deficiency present unique medical and rehabilitation challenges. Physical Medicine and Rehabilitation (PM&R) physicians are uniquely equipped to navigate these complexities. Prosthetic prescription and fabrication for children require balancing scientific principles with individual needs. A "one-size-fits-all" approach is ineffective. Many diverse factors impact prosthetic prescription and fabrication, including amputation level, residual limb characteristics, cognitive/developmental age, family goals, financial resources, and medical literacy.

Prosthetic Componentry in Upper Limb Prosthetic Restoration.

This article provides an overview of fundamental upper limb prosthesis concepts and componentry, including control systems (body-powered, externally powered, passive, and hybrid), sockets and suspension, and terminal devices.

Approaches to Prosthetic Limb Restoration in Resource-Limited Settings/Countries: 3 Dimensional Printing.

Much of the burden of living with a disability is concentrated among those populations least financially able to bear the burden. As the price of 3 dimensional (3D) printing decreases, individual access to this technology increases. 3D-printed prostheses can be designed specifically for use in resource-poor settings, including developing countries, to minimize the cost of consumable parts while optimizing durability in harsh environmental conditions.

Predicting Functional Outcomes Following Dysvascular Lower Limb Amputation: An Evidence Review of Personalizing Patient Outcomes.

Most research on people undergoing lower limb amputations for dysvascular disease summarizes average patient outcome risks and average associations between patient factors and these outcomes. More recently, the importance of predicting patient-specific outcomes based on individual factors (ie, personalized rehabilitation) has become evident. This article reviews the evidence and discusses the importance of the following: (1) predicting outcomes to facilitate amputation-level and prosthesis prescription decisions and (2) how prediction models can be leveraged to develop decision support tools to facilitate provider/patient shared decision-making to ensure decisions considering each individual patient's priorities and preferences. Examples of these tools are discussed and referenced.

Reintegration Following Amputation: A Biopsychosocial Approach.

Reintegration back into one's life following limb loss is heavily influenced by the interaction among the individual's mental health, environment, and physical factors (eg, pain and prostheses). While many patients experience posttraumatic growth and successfully reintegrate back into their lives, others have a more difficult adjustment. Interdisciplinary teams can best facilitate reintegration through early screening for barriers to reintegration such as depression, pain, body image, and inaccessible environments, to intervene early after amputation. With these barriers addressed, amputees may be able to return to driving and other valued activities more quickly, resulting in improved reintegration across life domains.

Innovations in Amputation Rehabilitation and Prosthetic Design.

This article reviews emerging surgical techniques and prosthetic innovations related to amputation rehabilitation. Osseointegration is discussed from conception to modern implant designs. Motor and sensory reinnervation techniques are reviewed and compared. Prosthetic socket casting, interface, and design innovations are discussed, including direct molded sockets, water casting, adjustable sockets, and magnetic suspension. Advanced components with hydraulic and microprocessor control, power and crossover prosthetic feet are described.

A novel procedure to automate the removal of PLI and motion artifacts using mode decomposition to enhance pattern recognition of sEMG signals for myoelectric control of prosthesis.

Hand Movement Recognition (HMR) with sEMG is crucial for artificial hand prostheses. HMR performance mostly depends on the feature information that is fed to the classifiers. However, sEMG often captures noise like power line interference (PLI) and motion artifacts. This may extract redundant and insignificant feature information, which can degrade HMR performance and increase computational complexity. This study aims to address these issues by proposing a novel procedure for automatically removing PLI and motion artifacts from experimental sEMG signals. This will make it possible to extract better features from the signal and improve the categorization of various hand movements. Empirical mode decomposition and energy entropy thresholding are utilized to select relevant mode components for artifact removal. Time domain features are then used to train classifiers (kNN, LDA, SVM) for hand movement categorization, achieving average accuracies of 92.36%, 93.63%, and 98.12%, respectively, across subjects. Additionally, muscle contraction efforts are classified into low, medium, and high categories using this technique. Validation is performed on data from ten subjects performing eight hand movement classes and three muscle contraction efforts with three surface electrode channels. Results indicate that the proposed preprocessing improves average accuracy by 9.55% with the SVM classifier, significantly reducing computational time.

Transplanted fibroblasts take the pressure.

Weight-bearing skin cells show promising therapeutic potential.

Artificial embodiment displaces cortical neuromagnetic somatosensory responses.

Integrating artificial limbs as part of one's body involves complex neuroplastic changes resulting from various sensory inputs. While somatosensory feedback is crucial, plastic processes that enable embodiment remain unknown. We investigated this using somatosensory evoked fields (SEFs) in the primary somatosensory cortex (S1) following the Rubber Hand Illusion (RHI), known to quickly induce artificial limb embodiment. During electrical stimulation of the little finger and thumb, 19 adults underwent neuromagnetic recordings before and after the RHI. We found early SEF displacement, including an illusion-brain correlation between extent of embodiment and specific changes to the first cortical response at 20 ms in Area 3b, within S1. Furthermore, we observed a posteriorly directed displacement at 35 ms towards Area 1, known to be important for visual integration during touch perception. That this second displacement was unrelated to extent of embodiment implies a functional distinction between neuroplastic changes of these components and areas. The earlier shift in Area 3b may shape extent of limb ownership, while subsequent displacement into Area 1 may relate to early visual-tactile integration that initiates embodiment. Here we provide evidence for multiple neuroplastic processes in S1-lasting beyond the illusion-supporting integration of artificial limbs like prostheses within the body representation.

Restoration of grasping in an upper limb amputee using the myokinetic prosthesis with implanted magnets.

The loss of a hand disrupts the sophisticated neural pathways between the brain and the hand, severely affecting the level of independence of the patient and the ability to carry out daily work and social activities. Recent years have witnessed a rapid evolution of surgical techniques and technologies aimed at restoring dexterous motor functions akin to those of the human hand through bionic solutions, mainly relying on probing of electrical signals from the residual nerves and muscles. Here, we report the clinical implementation of an interface aimed at achieving this goal by exploiting muscle deformation, sensed through passive magnetic implants: the myokinetic interface. One participant with a transradial amputation received an implantation of six permanent magnets in three muscles of the residual limb. A truly self-contained myokinetic prosthetic arm embedding all hardware components and the battery within the prosthetic socket was developed. By retrieving muscle deformation caused by voluntary contraction through magnet localization, we were able to control in real time a dexterous robotic hand following both a direct control strategy and a pattern recognition approach. In just 6 weeks, the participant successfully completed a series of functional tests, achieving scores similar to those achieved when using myoelectric controllers, a standard-of-care solution, with comparable physical and mental workloads. This experience raised conceptual and technical limits of the interface, which nevertheless pave the way for further investigations in a partially unexplored field. This study also demonstrates a viable possibility for intuitively interfacing humans with robotic technologies.