Prosthesis use in persons with lower- and upper-limb amputation

Health Disparities Across the Spectrum of Amputation Care: A Review of Literature

Limb loss is a common and disabling experience for patients, frequently caused by critical limb ischemia or deterioration of chronic wounds. Disparities in outcomes for prevention of amputation, level of amputation, and postamputation outcomes have been described. Understanding the nature of these disparities and the populations most affected can help clinicians and policymakers target interventions and programs. This article reviews existing literature regarding disparities in amputation care, including prevention methods, surgical outcomes, and postamputation outcomes. The authors identified several potential racial, socioeconomic, and gender disparities, particularly affecting Black, Native American, and Latino/a/x patients, female gender, and those in rural settings.

The Physiatrist's Approach to Limb Loss: Pre-amputation Through Lifelong Care

Limb-loss is a significant medical event with lifelong consequences, impacting various aspects of a patient's well-being. Care for these often-complex patients involves providers from many different specialties working toward a set of patient-centered goals. This article aims to highlight the important role of physiatrists in directing the interdisciplinary care for these patients. Through evidence-based concepts, the authors aim to lay a roadmap for comprehensive, longitudinal management of these patients from pre-amputation assessment through lifelong care.

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.

Duration, frequency, and factors related to lower extremity prosthesis use: systematic review and meta-analysis

PURPOSE

A systematic review and meta-analysis investigating the duration and frequency of lower extremity prosthesis use and what factors were associated with changes in their use.

MATERIALS AND METHODS

A search of PubMed, CINAHL, and Scopus over 20 years revealed 2409 articles. After review, 29 studies remained, representing 4814 participants with lower limb loss. Quality, funding, publication, and quantitative analyses were addressed.

RESULTS

The mean prosthesis use was 9.6 (5.3) hours/day and 6.4 (1.9) days/week. Distal amputation sites averaged more hours/day of prostheses use than proximal amputations (13.2 [3.2] vs. 10.8 [5.0], p < .001). After hemipelvectomy or hip dislocations, average prostheses use was less hours/day (6.0 [4.7]) than after transfemoral (12.9 [4.8]) or transtibial amputations (14.0 [4.5]) (p < .05). Pooled effects revealed an association between comorbidities and abandonment (OR 0.35, p = .03). The data supported six empirical evidence statements concerning age, sex, social support, amputation proximity, balance, skin condition, comorbidities, pain, falls, and fitness in association with changes in prosthesis utilization.

CONCLUSIONS

The study provided systematic data on lower-extremity prosthesis use, thus helping to inform clinical decision-making and patient education. It also elucidated a path for future studies focused on modifiable factors related to prosthesis use and related outcomes.Implications for rehabilitationLower limb loss can trigger costly and debilitating sequela, which could be mitigated by increased prosthesis use and functionality, but there is no consensus on how often prostheses are being used and what affects changes in their use.When counseling patients on what they can expect after a lower extremity amputation and to set goals, the aggregated means of 9.6 (5.3) hours per day and 6.4 (1.9) days per week can be informative.Individuals who use a lower extremity prosthesis or may have to use one in the future can increase their prosthesis use and mobility by limiting further health deterioration.Rehabilitative care involving the multidisciplinary prioritization of proper socket fit, fitness training, gait training, and social support is associated with increased prosthetic device usage.

Realizing Upper Extremity Bionic Limbs: Leveraging Neuroprosthetic Control Strategies

SUMMARY

Innovations in prosthetic devices and neuroprosthetic control strategies have opened new frontiers for the treatment and rehabilitation of individuals undergoing amputation. Commercial prosthetic devices are now available with sophisticated electrical and mechanical components that can closely replicate the functions of the human musculoskeletal system. However, to truly recognize the potential of such prosthetic devices and develop the next generation of bionic limbs, a highly reliable prosthetic device control strategy is required. In the past few years, refined surgical techniques have enabled neuroprosthetic control strategies to record efferent motor and stimulate afferent sensory action potentials from a residual limb with extraordinary specificity, signal quality, and long-term stability. As a result, such control strategies are now capable of facilitating intuitive, real-time, and naturalistic prosthetic experiences for patients with amputations. This article summarizes the current state of upper extremity neuroprosthetic devices and discusses the leading control strategies that are critical to the ongoing advancement of prosthetic development and implementation.

A method for quantitative spatial analysis of immunolabeled fibers at regenerative electrode interfaces

BACKGROUND

Regenerative electrodes are being explored as robust peripheral nerve interfaces for neuro-prosthetic control and sensory feedback. Current designs differ in electrode number, spatial arrangement, and porosity which impacts the regeneration, activation, and spatial distribution of fibers at the device interface. Knowledge of sensory and motor fiber distributions are important in optimizing selective fiber activation and recording.

NEW METHOD

We use confocal microscopy and immunofluorescence methods to conduct spatial analysis of immunolabeled fibers across whole nerve cross sections.

RESULTS

This protocol was implemented to characterize motor fiber distribution within 3 macro-sieve electrode regenerated (MSE), 3 silicone-conduit regenerated, and 3 unmanipulated control rodent sciatic nerves. Total motor fiber counts were 1485 [SD: +/- 50.11], 1899 [SD: +/- 359], and 5732 [SD: +/- 1410] for control, MSE, and conduit nerves respectively. MSE motor fiber distributions exhibited evidence of deviation from complete spatial randomness and evidence of dispersion and clustering tendencies at varying scales. Notably, MSE motor fibers exhibited clustering within the central portion of the cross section, whereas conduit regenerated motor fibers exhibited clustering along the periphery.

COMPARISON WITH EXISTING METHODS

Prior exploration of fiber distributions at regenerative interfaces was limited to either quadrant-based density analysis of randomly sampled subregions or qualitative description. This method extends existing sample preparation and microscopy techniques to quantitatively assess immunolabeled fiber distributions within whole nerve cross-sections.

CONCLUSIONS

This approach is an effective way to examine the spatial organization of fiber subsets at regenerative electrode interfaces, enabling robust assessment of fiber distributions relative to electrode arrangement.

Working with partial hand prostheses: An investigation into experiences of clinicians

BACKGROUND

Individuals living with partial hand absence often face challenges in performing everyday tasks and fully participating in society. Prosthetic devices offer a range of benefits, including improved functionality or cosmesis. However, partial hand devices can be rejected by users. In addition, there is a lack of evidence that establishes methods or factors influencing the clinical prescription of prosthetics specifically designed for this population.

OBJECTIVES

The objectives of the investigation were to gain understanding of who is prescribing partial hand prosthetics and the factors which influence device selection.

STUDY DESIGN

A 36-item anonymous online survey was designed on Qualtrics and distributed to clinicians. The survey contained multiple-choice, Likert-type, closed, and open-ended questions.

METHODS

Quantitative and qualitative analyses were performed on Qualtrics and Microsoft Excel.

RESULTS

Thirty-seven clinicians from various occupations participated. The majority agreed that outcome measures are useful for assessing partial hand prosthetics but suggested room for improvement. Although clinicians use various outcome measurement tools, there is a lack of tools specifically tailored to this population. Factors such as existing function, occupation, and hobbies were identified as important when selecting prosthetic devices for users. Funding influenced the range of partial hand devices available for prescription.

CONCLUSIONS

The prescription process involves multiple stakeholders. Various factors, including funding and user satisfaction, must be considered in the decision-making process. There is a lack of specific outcome measures recommended for evaluating prosthetics in this population. However, providing loaner units before final prescription yields positive outcomes.

Using Electrical Muscle Stimulation to Enhance Electrophysiological Performance of Agonist-Antagonist Myoneural Interface

The agonist-antagonist myoneural interface (AMI), a surgical method to reinnervate physiologically-relevant proprioceptive feedback for control of limb prostheses, has demonstrated the ability to provide natural afferent sensations for limb amputees when actuating their prostheses. Following AMI surgery, one potential challenge is atrophy of the disused muscles, which would weaken the reinnervation efficacy of AMI. It is well known that electrical muscle stimulus (EMS) can reduce muscle atrophy. In this study, we conducted an animal investigation to explore whether the EMS can significantly improve the electrophysiological performance of AMI. AMI surgery was performed in 14 rats, in which the distal tendons of bilateral solei donors were connected and positioned on the surface of the left biceps femoris. Subsequently, the left tibial nerve and the common peroneus nerve were sutured onto the ends of the connected donor solei. Two stimulation electrodes were affixed onto the ends of the donor solei for EMS delivery. The AMI rats were randomly divided into two groups. One group received the EMS treatment (designated as EMS_on) regularly for eight weeks and another received no EMS (designated as EMS_off). Two physiological parameters, nerve conduction velocity (NCV) and motor unit number, were derived from the electrically evoked compound action potential (CAP) signals to assess the electrophysiological performance of AMI. Our experimental results demonstrated that the reinnervated muscles of the EMS_on group generated higher CAP signals in comparison to the EMS_off group. Both NCV and motor unit number were significantly elevated in the EMS_on group. Moreover, the EMS_on group displayed statistically higher CAP signals on the indirectly activated proprioceptive afferents than the EMS_off group. These findings suggested that EMS treatment would be promising in enhancing the electrophysiological performance and facilitating the reinnervation process of AMI.

The role of the purposeful shared decision making model in vascularized composite allotransplantation

For some patients who have lost the lower part of an arm, hand transplant offers the possibility of receiving a new limb with varying degrees of sensation and function. This procedure, Vascularized Composite Allotransplantation (VCA), is demanding for patients and their care community and comes with significant risks. As a high-stakes decision, patients interested in VCA are subject to extensive clinical evaluation and eligibility decision making. Patients and their care community must also decide if hand transplant (versus other approaches including rehabilitative therapies with or without prosthesis) is right for them. This decision making is often confusing and practically and emotionally fraught. It is complicated in four ways: by the numerous beneficial and harmful potential effects of hand transplant or other options, the number of people affected by VCA and the diverse or conflicting positions that they may hold, the practical demands and limitations of the patient's life situation, and the existential significance of limb loss and transplant for the patient's being. Patients need support in working through these treatment determining issues. Evaluation does not provide this support. Shared decision making (SDM) is a method of care that helps patients think, talk, and feel their way through to the right course of action for them. However, traditional models of SDM that focus on weighing possible beneficial and harmful effects of treatments are ill-equipped to tackle the heterogeneous issues of VCA. A recent model, Purposeful SDM extends the range of troubling issues that SDM can help support beyond opposing effects, to include conflicting positions, life situations, and existential being. In this paper we explore the pertinence of these issues in VCA, methods of SDM that each require of clinicians, the benefits of supporting patients with the breadth of issues in their unique problematic situations, implications for outcomes and practice, and extend the theory of the Purposeful SDM model itself based on the issues present in hand transplant decision making.

Prosthesis Usage and Functional Status in Upper Limb Amputees: A Prospective Cross-Sectional Study

Introduction Amputation poses significant challenges encompassing psychological, physical, and socio-economic dimensions, impacting individuals and society at large. In India, a substantial portion of the population faces loco-motor disabilities, with amputees forming a notable segment. Prosthetic rehabilitation plays a crucial role in mitigating the consequences of limb loss, aiming to restore autonomy post-amputation. Methods A prospective cross-sectional observational study was conducted over 18 months, from November 2018 to May 2020, involving unilateral upper limb amputees (ULAs) aged over 18 years. A consecutive cohort of 33 patients, predominantly male (30 males and three females), with a mean age of 43 ± 12 years (median: 43 years; range: 20-67 years), was prospectively enrolled in the study. Participants had completed at least one month of post-prosthetic fitment and were actively attending outpatient or prosthetic checkout clinics. The study utilized the Manipal Prosthetic Rehabilitation Success (PRS) score and the Orthotics and Prosthetics User Survey Upper Extremity Functional Status (OPUS UEFS) score to assess prosthesis usage and functional status. Statistical analyses included descriptive statistics, Chi-square tests, Mann-Whitney U tests, Kruskal-Wallis tests, and multivariate logistic regression analysis. Results The study revealed insights into upper limb prosthesis usage in India, highlighting factors influencing the success and challenges faced by ULAs. Associations were found between the success of prosthesis usage and several factors: occupation type (p=0.012), the side of amputation involving non-dominant limbs (p=0.033), comfort level (p=0.002), and prosthesis weight (p=0.029). Comfort level emerged as a primary predictor of usage success. The OPUS UEFS scores indicated varying levels of satisfaction and usage patterns among participants, with some utilizing prostheses for specific tasks while others for broader activities. Comfort level demonstrated a statistically significant difference in OPUS UEFS scores, favoring comfortable prostheses (p=0.020). Additionally, the mean OPUS UEFS score for patients with satisfactory or good prosthesis use was 53 ± 11 (median: 55; range: 22-64), compared to 45 ± 13 (median: 43; range: 18 - 64) in those with poor prosthesis use, with the difference nearing statistical significance (p=0.058). Conclusion The study sheds light on the landscape of upper limb prosthesis usage in India, emphasizing the need for tailored interventions based on individual needs and cultural contexts. The findings underscore the importance of comfort, side of amputation involving non-dominant limbs, occupation type, and prosthesis weight in determining the success of prosthesis usage. Opportunities exist to enhance upper limb prosthetic care in India by addressing cultural nuances and refining assessment tools to better suit the Indian population.

Transhumeral prosthesis use affects upper body kinematics and kinetics

BACKGROUND

Transhumeral (TH) limb loss leads to loss of body mass and reduced shoulder range of motion. Despite most owning a prosthesis, prosthesis abandonment is common. The consequence of TH limb loss and prosthesis use and disuse during gait may be compensation in the upper body, contributing to back pain or injury. Understanding the impact of not wearing a TH prosthesis on upper body asymmetries and spatial-temporal aspects of gait will inform how TH prosthesis use and disuse affects the body.

RESEARCH QUESTION

Does TH limb loss alter upper body asymmetries and spatial-temporal parameters during gait when wearing and not wearing a prosthesis compared to able-bodied controls?

METHODS

Eight male TH limb loss participants and eight male control participants completed three gait trials at self-selected speeds. The TH limb loss group performed trials with and without their prosthesis. Arm swing, trunk angular displacement, trunk-pelvis moment, and spatial-temporal aspects were compared using non-parametric statistical analyses.

RESULTS

Both TH walking conditions showed greater arm swing in the intact limb compared to the residual (p≤0.001), resulting in increased asymmetry compared to the control group (p≤0.001). Without the prosthesis, there was less trunk flexion and lateral flexion compared to the control group (p≤0.001). Maximum moments between the trunk and pelvis were higher in the TH group than the control group (p≤0.05). Spatial-temporal parameters of gait did not differ between the control group and either TH limb loss condition.

SIGNIFICANCE

Prosthesis use affects upper body kinematics and kinetics, but does not significantly impact spatial-temporal aspects of gait, suggesting these are compensatory actions. Wearing a prosthesis helps achieve more normative upper body kinematics and kinetics than not wearing a prosthesis, which may help limit back pain. These findings emphasize the importance of encouraging at least passive use of prostheses for individuals with TH limb loss.

Prosthesis usability experience is associated with extent of upper limb prosthesis adoption: A Structural Equation Modeling (SEM) analysis

Factors associated with upper limb prosthesis adoption are not well understood. In this study, we explored how prosthesis usability experience relates to the extent of prosthesis adoption through the development of a structural equation model (SEM). First, items related to prosthesis usability were developed and refined using cognitive testing and pilot testing and employed in a survey of 402 prosthesis users (mean age 61.7 (sd 14.4), 77.1% Veterans). The SEM examined two unidimensional latent constructs: Prosthesis Usability Experience and Prosthesis Adoption-and each had multiple measured indicators. SEMs tested direct as well as moderating and mediating effects between the latent constructs and covariates related to demographics and prosthesis type. SEM found a significant positive association between Prosthesis Usability Experience and Extent of Prosthesis Adoption. Several covariates had direct effects on prosthesis adoption: 1) Extent of Prosthesis Adoption was lower for those with transhumeral and shoulder amputation, and higher for those with bilateral amputation, compared to the reference group with unilateral transradial amputation and 2) Myoelectric multiple degree of freedom (multi-DOF) prosthesis use was associated with lower Extent of Prosthesis Adoption, compared to body-powered prosthesis use. Myoelectric multi-DOF use also modified the effect of Prosthesis Usability Experience on Extent of Prosthesis Adoption. For those with bilateral ULA, the strength of the relationship between Prosthesis Usability Experience and Extent of Prosthesis Adoption was reduced. Findings suggest that in order to increase prosthesis adoption, prosthetics developers and rehabilitation providers should focus on implementing strategies to improve prosthesis usability experience. New Prosthesis Usability Experience measures could be used to identify persons at greater risk for poor prosthesis adoption and target interventions to increase prosthesis use.

Three-dimensional printing technology applied to the production of prosthesis: A systemic narrative review

The purpose of this scoping review was to investigate the effects of 3-dimensional (3D)-printed prostheses. Articles published up to August 19, 2023, were searched in the PubMed, Cochrane Library, Embase, and Scopus databases. The search terms used were "3D printed prosthesis," "3D printed prostheses," "3D printed prosthe*," "3D printed artificial arm," "3D printed artificial leg," "3D printing prosthesis," "3D printing prostheses," "3D printing prosthe*," "3D printing artificial arm," and "3D printing artificial leg." This review included studies that applied 3D-printed prostheses to upper- or lower-limb amputees. Case reports, conference abstracts, presentations, reviews, and unidentified articles were excluded from the analysis. A total of 937 articles were identified, 11 of which were included after confirming eligibility through the title, abstract, and full text. The results indicated that the 3D-printed prostheses demonstrated the ability to substitute for the functions of impaired limbs, similar to conventional prostheses. Notably, the production cost and weight were reduced compared with those of conventional prostheses, increasing patient satisfaction. The use of 3D-printed prostheses is expected to gain prominence in future clinical practice. However, concerns regarding the durability of 3D-printed prostheses have increased among users. Therefore, there is an ongoing need to explore highly durable materials that can withstand the weight of the user without breaking easily. In addition, advancements are required in technologies that enable the depiction of various skin tones and the production of smaller-sized prostheses suitable for clothing.

The lived experience of military beneficiaries with amputations at the hip and pelvic level

BACKGROUND

Hip- and pelvic-level amputations are devastating injuries that drastically alter patient function and quality of life. This study examined the experience of military beneficiaries with a hip- or pelvic-level amputation to better characterize their challenges and specific needs and to optimize treatment in the future.

METHODS

We conducted a retrospective review of the Military Health System and identified 118 patients with a history of one or more amputation(s) at the hip or pelvic level between October 2001 and September 2017. Surviving participants (n = 97) were mailed a letter which explained the details of the study and requested participation in a telephonic interview. A total of six individuals (one female, five males) participated in structured interviews.

RESULTS

The study group included four participants with hip disarticulations and two participants with hemipelvectomies (one internal, one external). All six participants reported significant challenges with activities related to prosthetic use, mobility, residual limb health, pain, gastrointestinal and genitourinary function, psychiatric health, and sexual function.

CONCLUSIONS

These interviews highlight the unique needs of individuals with hip- and pelvic-level amputations and may improve access to higher echelons of care that would enhance the function and quality of life for these participants.

A scoping review of digital fabrication techniques applied to prosthetics and orthotics: Part 1 of 2-Prosthetics

BACKGROUND

Traditionally, the manufacture of prostheses is time-consuming and labor-intensive. One possible route to improving access and quality of these devices is the digitalizing of the fabrication process, which may reduce the burden of manual labor and bring the potential for automation that could help unblock access to assistive technologies globally.

OBJECTIVES

To identify where there are gaps in the literature that are creating barriers to decision-making on either appropriate uptake by clinical teams or on the needed next steps in research that mean these technologies can continue on a pathway to maturity.

STUDY DESIGN

Scoping literature review.

METHODS

A comprehensive search was completed in the following databases: Allied and Complementary Medicine Database, MEDLINE, Embase, Global Health Archive, CINAHL Plus, Cochrane Library, Web of Science, Association for Computing Machinery, Institute of Electrical and Electronics Engineers, and Engineering Village, resulting in 3487 articles to be screened.

RESULTS

After screening, 130 lower limb prosthetic articles and 117 upper limb prosthetic articles were included in this review. Multiple limitations in the literature were identified, particularly a lack of long-term, larger-scale studies; research into the training requirements for these technologies and the necessary rectification processes; and a high range of variance of production workflows and materials which makes drawing conclusions difficult.

CONCLUSIONS

These limitations create a barrier to adequate evidence-based decision-making for clinicians, technology developers, and wider policymakers. Increased collaboration between academia, industry, and clinical teams across more of the pathway to market for new technologies could be a route to addressing these gaps.

A scoping review on upper extremity prostheses: Satisfaction, barriers, and their implications in resource-limited countries

The rates of prosthetic abandonment are not extensively understood especially in resource-limited countries. A scoping review was conducted to examine the literature on the satisfaction with and barriers to using specifically upper limb prostheses. A systematic search of the literature identified 425 studies. After reviewing the articles using predetermined inclusion and exclusion criteria, 7 cross-sectional studies were included in the final review. Barriers to the use of upper limb prostheses include the characteristics of the prosthesis (type, comfort, weight, functionality, price, and availability) and individual patient factors (recent prosthetic user, level of amputation, congenital and accidental limb loss, pain, and duration between amputation and prosthetic fitting). Considering tailored prosthetic design and funding may result in improved prosthetic adherence.

Reliability and validity of the Turkish version of the Prosthesis Embodiment Scale for Lower Limb Amputees

BACKGROUND

Prosthetic embodiment is the perception of the prosthesis as a part of the body, and it is important for acceptance and adequate and effective use of the prosthesis.

OBJECTIVE

The aim of this study was to investigate the validity and reliability of the Turkish version of the Prosthesis Embodiment Scale for Lower Limb Amputees.

METHODS

This cross-sectional study included a total of 88 lower limb amputees. Internal consistency was evaluated using Cronbach α coefficient. The test-retest reliability of the scale, which was reapplied after 7-10 d, was evaluated using intraclass correlation coefficient. Principal component analysis with Varimax rotation was used to analyze the factor structure. Spearman correlation coefficient with Trinity Amputation and Prosthesis Experience Scale subscales was calculated for concurrent validity.

RESULTS

The mean age of the participants was 45.13 ± 15.05 years, and 76.1% were male. Internal consistency (Cronbach α = 0.905) and test-retest reliability (intraclass correlation coefficient = 0.822) were high. 76.1% of the total variance could be explained by the 3 dimensions. Significant correlation was found with the Trinity Amputation and Prosthesis Experience Scale subscales (r = 0.542 for psychosocial adjustment subscale, r = -0.452 for activity restriction subscale, r = 0.490 for prosthesis satisfaction subscale, p < 0.001).

CONCLUSIONS

The results of this study showed that the Turkish version of the Prosthesis Embodiment Scale for Lower Limb Amputees is a valid and reliable tool that can be used to evaluate prosthetic rehabilitation outcomes.

Extended physiological proprioception is affected by transhumeral Socket-Suspended prosthesis use

The objective of this study was to define targeted reaching performance without visual information for transhumeral (TH) prosthesis users, establishing baseline information about extended physiological proprioception (EPP) in this population. Subjects completed a seated proprioceptive targeting task under simultaneous motion capture, using their prosthesis and intact limb. Eight male subjects, median age of 58 years (range 29-77 years), were selected from an ongoing screening study to participate. Five subjects had a left-side TH amputation, and three a right-side TH amputation. Median time since amputation was 9 years (range 3-54 years). Four subjects used a body-powered prosthetic hook, three a myoelectric hand, and one a myoelectric hook. The outcome measures were precision and accuracy, motion of the targeting hand, and joint angular displacement. Subjects demonstrated better precision when targeting with their intact limb compared to targeting with their prosthesis, 1.9 cm2 (0.8-3.0) v. 7.1 cm2 (1.3-12.8), respectively, p = 0.008. Subjects achieved a more direct reach path ratio when targeting with the intact limb compared to with the prosthesis, 1.2 (1.1-1.3) v. 1.3 (1.3-1.4), respectively, p = 0.039 The acceleration, deceleration, and corrective phase durations were consistent between conditions. Trunk angular displacement increased in flexion, lateral flexion, and axial rotation while shoulder flexion decreased when subjects targeted with their prosthesis compared to the intact limb. The differences in targeting precision, reach patio ratio, and joint angular displacements while completing the targeting task indicate diminished EPP. These findings establish baseline information about EPP in TH prosthesis users for comparison as novel prosthesis suspension systems become more available to be tested.

A disparity in prosthetic access for Ecuadorians with lower-limb amputation

BACKGROUND

Individuals with disabilities in low- and middle-income countries face barriers to rehabilitation services, including prosthetic care. Many countries, such as Ecuador, have adapted policies toward achieving universal health care coverage. For optimal functional outcomes, understanding the physical potential of prosthetic users is critical for appropriate prosthetic services.

OBJECTIVE

To determine the association between the functional level of Ecuadorians with lower-limb amputations and the functional level of their prosthetic componentry.

STUDY DESIGN

Retrospective study.

METHODS

A data set containing functional level (K-Level) of Ecuadorians with lower-limb amputations and the K-Level of their prosthesis was analyzed.

RESULTS

A diverse cohort of 164 participants with unilateral lower-limb amputation was recruited. Most participants were male (76.8%) with transfemoral amputations (56.1%) due to traumatic causes (51.2%). There was a small, positive, and statistically significant correlation between participants' functional levels and prosthetic componentry. Participants's functional levels were typically superior (median = 3) to their prostheses' functional abilities (median = 1), and 37.2% of participants did not have a prosthesis at the time of assessment.

CONCLUSIONS

These data indicated that participants whose physical ability exceeded basic ambulation lacked access to prostheses to match their functional abilities. The detailed disparity between physical potential and prosthetic access derived from the study's analysis supports investment into high functioning prosthetic componentry and further investigation into where gaps in care exist.

A Circular, Wireless Surface-Electromyography Array

Commercial, high-tech upper limb prostheses offer a lot of functionality and are equipped with high-grade control mechanisms. However, they are relatively expensive and are not accessible to the majority of amputees. Therefore, more affordable, accessible, open-source, and 3D-printable alternatives are being developed. A commonly proposed approach to control these prostheses is to use bio-potentials generated by skeletal muscles, which can be measured using surface electromyography (sEMG). However, this control mechanism either lacks accuracy when a single sEMG sensor is used or involves the use of wires to connect to an array of multiple nodes, which hinders patients' movements. In order to mitigate these issues, we have developed a circular, wireless s-EMG array that is able to collect sEMG potentials on an array of electrodes that can be spread (not) uniformly around the circumference of a patient's arm. The modular sEMG system is combined with a Bluetooth Low Energy System on Chip, motion sensors, and a battery. We have benchmarked this system with a commercial, wired, state-of-the-art alternative and found an r = 0.98 (p < 0.01) Spearman correlation between the root-mean-squared (RMS) amplitude of sEMG measurements measured by both devices for the same set of 20 reference gestures, demonstrating that the system is accurate in measuring sEMG. Additionally, we have demonstrated that the RMS amplitudes of sEMG measurements between the different nodes within the array are uncorrelated, indicating that they contain independent information that can be used for higher accuracy in gesture recognition. We show this by training a random forest classifier that can distinguish between 6 gestures with an accuracy of 97%. This work is important for a large and growing group of amputees whose quality of life could be improved using this technology.

Health Care Utilization After Major Limb Loss in Adults (18-64) Receiving Care in the Military Health System From 2001 to 2017

OBJECTIVE

To characterize and quantify health care utilization of Military Health System beneficiaries with major limb loss.

DESIGN

Retrospective cohort study.

SETTING

Military treatment facilities and civilian health care facilities that accept TRICARE insurance across the United States.

PARTICIPANTS

A total 5950 adult Military Health System beneficiaries with major limb amputation(s) acquired between January 1st, 2001, and September 30th, 2017 (N=5950).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

This study was an exploratory analysis designed to identify common care specialties, services, and devices utilized by Military Health System beneficiaries with major limb loss.

RESULTS

Most beneficiaries were retirees/dependents (63.3%), men (73.1%), and had a single amputation (88.7%), with a mean age of 42 years. Differences between beneficiary categories were found. Active-duty service members used a larger proportion of inpatient, emergency, primary care, physical and occupational therapy, prosthetics and orthotics, physical medicine and rehabilitation, and psychiatry services than retirees/dependents. Most common procedures included "revision of amputation stump" (57.2%) for the active-duty population and "other amputation below knee" (24.3%) for the retirees/dependents.

CONCLUSIONS

These findings highlight the rehabilitation trajectories of beneficiaries receiving treatment for major limb loss in military and civilian care settings. The results could inform staffing decisions and training programs for military treatment facilities, American trauma centers, rehabilitation hospitals, and outpatient health care providers treating individuals with amputation.

Advances in prosthetic technology: a perspective on ethical considerations for development and clinical translation

Technological advancements of prostheses in recent years, such as haptic feedback, active power, and machine learning for prosthetic control, have opened new doors for improved functioning, satisfaction, and overall quality of life. However, little attention has been paid to ethical considerations surrounding the development and translation of prosthetic technologies into clinical practice. This article, based on current literature, presents perspectives surrounding ethical considerations from the authors' multidisciplinary views as prosthetists (HG, AM, CLM, MGF), as well as combined research experience working directly with people using prostheses (AM, CLM, MGF), wearable technologies for rehabilitation (MGF, BN), machine learning and artificial intelligence (BN, KKQ), and ethics of advanced technologies (KKQ). The target audience for this article includes developers, manufacturers, and researchers of prosthetic devices and related technology. We present several ethical considerations for current advances in prosthetic technology, as well as topics for future research, that may inform product and policy decisions and positively influence the lives of those who can benefit from advances in prosthetic technology.

Types, functions and mechanisms of robot-assisted intervention for fall prevention: A systematic scoping review

BACKGROUND

Any individual may experience accidental falls, particularly older adults. Although robots can prevent falls, knowledge of their fall-preventive use is limited.

OBJECTIVE

To explore the types, functions, and mechanisms of robot-assisted intervention for fall prevention.

METHODS

A systematic scoping review of global literature published from inception to January 2022 was conducted according to Arksey and O'Malley's five-step framework. Nine electronic databases, namely, PubMed, Embase, CINAHL, IEEE Xplore, the Cochrane Library, Scopus, Web of Science, PsycINFO, and ProQuest, were searched.

RESULTS

Seventy-one articles were found with developmental (n = 63), pilot (n = 4), survey (n = 3), and proof-of-concept (n = 1) designs across 14 countries. Six types of robot-assisted intervention were found, namely cane robots, walkers, wearables, prosthetics, exoskeletons, rollators, and other miscellaneous. Five main functions were observed including (i) detection of user fall, (ii) estimation of user state, (iii) estimation of user motion, (iv) estimation of user intentional direction, and (v) detection of user balance loss. Two categories of mechanisms of robots were found. The first category was executing initiation of incipient fall prevention such as modeling, measurement of user-robot distance, estimation of center of gravity, estimation and detection of user state, estimation of user intentional direction, and measurement of angle. The second category was achieving actualization of incipient fall prevention such as adjust optimal posture, automated braking, physical support, provision of assistive force, reposition, and control of bending angle.

CONCLUSIONS

Existing literature regarding robot-assisted intervention for fall prevention is in its infancy. Therefore, future research is required to assess its feasibility and effectiveness.

Prosthesis nonuse and discontinuation in United States veterans with major limb amputation: Results of a national survey

BACKGROUND

Prosthesis use in persons with amputation can improve mobility and functional independence. Better understanding of the reasons for and outcomes associated with prosthesis nonuse is important to optimize function and long-term health in persons with amputation.

OBJECTIVES

Study objectives were to describe the rate, reasons for, and factors associated with never using or discontinuing prosthesis use in United States (US) veterans with amputation.

STUDY DESIGN

Cross-sectional study design.

METHODS

The study used an online survey to assess prosthesis use and satisfaction in veterans with upper-limb and lower-limb amputation. Survey participation invitations were distributed by email, text message, and mail to 46,613 potential participants.

RESULTS

The survey response rate was 11.4%. After exclusions, an analytic sample of 3,959 respondents with a major limb amputation was identified. The sample was 96.4% male; 78.3% White, with mean age of 66.9; and mean of 18.2 years since amputation. The rate of never using a prosthesis was 8.2%, and the rate of prosthesis discontinuation was 10.5%. Functionality (62.0%), undesirable prosthesis characteristics (56.9%), and comfort (53.4%) were the most common reasons for discontinuation. After controlling for the amputation subgroup, the odds of prosthesis discontinuation were higher for those with unilateral upper-limb amputation, female gender, White race (compared with Black race), diabetes, above-knee amputation, and lower prosthesis satisfaction. Prosthesis satisfaction and quality of life were highest for current prosthesis users.

CONCLUSIONS

This study adds new understanding regarding the rate and reasons for prosthesis nonuse in veterans and highlights the important relationship between prosthesis discontinuation and prosthesis satisfaction, quality of life, and satisfaction with life.

Replantation versus transplantation: Where do we stand?

PURPOSE

Despite advances in extremity trauma care and reconstructive microsurgery, management of the traumatic amputations remains a challenge. The majority of patients will forever experience some level of disability even with replantation or advanced prosthetics. The goal of this article is to familiarize hand and reconstructive surgeons with the current state of upper extremity transplantation, so they better can educate their amputee patients regarding this as an option following limb loss.

METHODS

Current literature, in addition to the international registry on hand and composite tissue transplantation, was reviewed to assemble a summary of outcomes in upper extremity replantation and transplantation.

RESULTS

Sensory and functional outcomes of replantation and transplantation are comparable. Reported complications of immunosuppression are similar to those of other solid organ transplants. The financial cost of hand transplantation is high, but comparable to the lifetime cost of prosthesis use.

CONCLUSION

While the risk of immunosuppression is a serious consideration for patients pursuing hand transplantation, in the well-selected and informed patient, hand transplantation can dramatically improve patient reported to outcomes and quality of life.

Key Modifiable Factors in Community Participation Among Adults With Lower Limb Amputation

OBJECTIVE

The aim of the study is to identify factors that may predict community participation among adults with lower limb amputation.

DESIGN

This study is a secondary analysis of a cross-sectional data set, including 126 community-dwelling adults, ≥1 yr after unilateral transfemoral- ( n = 44; mean age = 59 ± 14 yrs) or transtibial-level amputation ( n = 82; mean age = 59 ± 14 yrs) seen in an outpatient limb loss clinic. Participation was assessed with the Community Integration Questionnaire. Factors, that is, demographics, comorbidities, prosthesis use per the Houghton Scale, Socket Comfort Score, assistive device use, falls history, and activity level per General Practice Physical Activity Questionnaire were evaluated. Moreover, balance confidence per the Activities-Specific Balance Confidence Scale, mobility per the Locomotor Capabilities Index, fast and self-selected gait speed per 10-meter walk tests, and functional mobility via Timed Up and Go were also included.

RESULTS

Community participation was correlated with several factors ( P ≤ 0.050). Stepwise regression of correlated factors found absence of peripheral neuropathy and greater self-reported physical activity, balance confidence, and prosthesis use, as the strongest correlates, collectively explaining 50.1% of the variance in community participation post-lower limb amputation.

CONCLUSIONS

Findings identify key modifiable factors for consideration in future prospective research seeking to enhance community reintegration and participation among adults living with a unilateral transfemoral- or transtibial-level amputation.

Low-cost prosthetic feet for underserved populations: A comparison of gait analysis and mechanical stiffness

BACKGROUND

Lower-limb loss is an ongoing cause of disability throughout the world. Despite advancements in prosthetic technologies, there are numerous underserved populations in need of effective low-cost prosthetic foot options.

OBJECTIVE

To evaluate the biomechanical performance of several low-cost prosthetic feet, using a combination of instrumented gait analysis and mechanical stiffness testing.

STUDY DESIGN

Randomized crossover with additional case study.

METHODS

We compared the solid-ankle-cushioned-heel (SACH), Jaipur, and Niagara feet with carbon fiber feet. Mechanical stiffness was evaluated using a cantilever-style bending test at 2 angles that was designed to mimic late stance gait loading. Eight below-knee amputees participated in the gait analysis, which focused on foot and ankle motion and energetics.

RESULTS

Metric analysis showed significant differences among feet in ankle motion and power as well as distal-to-shank power, with SACH showing reduced ankle motion and positive work compared with the other feet. Waveform analysis additionally revealed a compensatory knee flexion moment in SACH and a knee extension moment in Niagara and Jaipur during midstance. In mechanical stiffness testing, SACH had the highest stiffness, with Niagara and carbon fiber roughly similar, and Jaipur the most compliant with the greatest hysteresis.

CONCLUSIONS

There may be an optimal stiffness range for future prosthesis designs that maximizes propulsive energy. This may be achieved by combining some characteristics of Jaipur and Niagara feet in new designs. Ultimately, optimizing stiffness and energetics for gait biomimicry while maintaining cost, availability, and versatility across cultures will alleviate the effects of limb loss among underserved populations.

Prevalence and predictors of unmet need for upper limb prostheses: An observational cohort study

Introduction

No prior studies have examined the prevalence of unmet prosthesis need among prosthesis nonusers.

Objectives

The aim of this study was to describe the prevalence of unmet need for an upper-limb prosthesis and identify independent covariates associated with unmet need for a prosthesis.

Study Design

This study is a telephone survey of 742 persons with upper-limb amputation (ULA).

Methods

Differences between users and nonusers and between nonusers with and without an unmet need were compared statistically. Covariates associated with unmet need P ≤ 0.2 in bivariate analyses were included in a multivariate logistic regression model predicting unmet need.

Results

Odds of unmet need were higher for those who stopped using a prosthesis within the past year compared with 20 years or more ago (odds ratio [OR], 4.30; 95% confidence interval [CI], 1.28–14.51) and those on disability (OR, 4.01; 95% CI, 0.95–16.85). Odds of unmet need were lower for those with higher upper-limb function scores (OR, 0.94; 95% CI, 0.96–1.00), who were unemployed versus employed/student (OR, 0.15; 95% CI, 0.02–0.98), and those who had abandoned a prior prosthesis because it was “too much fuss” (OR, 0.41; 95% CI, 0.18–0.92).

Conclusions

Unmet need was prevalent, impacting approximately 50% of persons with upper-limb amputation who were not using a device and 14% who reported never having used a prosthesis. Independent correlates of greater unmet included worse upper-limb function, prosthesis use within the prior year, and disability status. Correlates of lesser unmet need included being unemployed and having abandoned a prosthesis because it was perceived as an undue burden. Further studies are needed to understand barriers to prosthesis use among nonusers with an unmet need.

Clinical Relevance

Persons with ULA who do not use a prosthesis should be reevaluated regularly to identify unmet needs. Our findings suggest recent prosthesis users, those with poorer upper-limb function, and those who are employed or on disability are more likely to have unmet needs.

The association of the localized pain sensitivity in the residual limb and prosthesis use in male veterans with transtibial amputation

The association of localized pain sensitivity in the residual limb and prosthesis use has clinical implications, however, rarely been assessed. This study aimed to investigate pain sensitivity and explore its range, variability, and association with prosthesis use alongside other demographic and clinical characteristics of veterans with transtibial amputation. Pain sensitivity was determined as pressure pain threshold (PPT) and pressure tolerance (PT) in 19 male veterans with a mean age of 49.5 years using pressure algometry at 12 anatomical locations on‎ the residual limb. A comparison of pain sensitivity at each location, and among anatomical locations and participants was explored using independent t-test, analysis of variance, and Kruskal-Wallis tests, respectively. Pain sensitivity range (PSR), the difference between PT and PPT, was significantly different (p < 0.05) at mid-patellar tendon, medial tibial flare, and the distal end of the tibia. The lowest PPT and PT (20.5 and 33 Ncm-2, p = 0.13) were recorded at the distal end of the residual limb, and the highest PPT and PT (73.4 and 94.3 Ncm-2, p = 0.03) were recorded at the mid-patellar tendon. Pain sensitivity was significantly different among anatomical locations and participants. The correlation tests (Pearson and partial eta squared) showed non-significant associations of pain sensitivity with participants' demographic and clinical characteristics except for daily prosthesis use. The mid-patellar tendon, medial tibial flare, and distal end of the tibia revealed the lowest pain hypersensitivity ‎due to higher PSR. Longer daily prosthesis use was associated with increased pain sensitivity.

Revolutionizing Prosthetic Design with Auxetic Metamaterials and Structures: A Review of Mechanical Properties and Limitations

Prosthetics have come a long way since their inception, and recent advancements in materials science have enabled the development of prosthetic devices with improved functionality and comfort. One promising area of research is the use of auxetic metamaterials in prosthetics. Auxetic materials have a negative Poisson's ratio, which means that they expand laterally when stretched, unlike conventional materials, which contract laterally. This unique property allows for the creation of prosthetic devices that can better conform to the contours of the human body and provide a more natural feel. In this review article, we provide an overview of the current state of the art in the development of prosthetics using auxetic metamaterials. We discuss the mechanical properties of these materials, including their negative Poisson's ratio and other properties that make them suitable for use in prosthetic devices. We also explore the limitations that currently exist in implementing these materials in prosthetic devices, including challenges in manufacturing and cost. Despite these challenges, the future prospects for the development of prosthetic devices using auxetic metamaterials are promising. Continued research and development in this field could lead to the creation of more comfortable, functional, and natural-feeling prosthetic devices. Overall, the use of auxetic metamaterials in prosthetics represents a promising area of research with the potential to improve the lives of millions of people around the world who rely on prosthetic devices.

Long-term upper-extremity prosthetic control using regenerative peripheral nerve interfaces and implanted EMG electrodes

Objective.Extracting signals directly from the motor system poses challenges in obtaining both high amplitude and sustainable signals for upper-limb neuroprosthetic control. To translate neural interfaces into the clinical space, these interfaces must provide consistent signals and prosthetic performance.Approach.Previously, we have demonstrated that the Regenerative Peripheral Nerve Interface (RPNI) is a biologically stable, bioamplifier of efferent motor action potentials. Here, we assessed the signal reliability from electrodes surgically implanted in RPNIs and residual innervated muscles in humans for long-term prosthetic control.Main results.RPNI signal quality, measured as signal-to-noise ratio, remained greater than 15 for up to 276 and 1054 d in participant 1 (P1), and participant 2 (P2), respectively. Electromyography from both RPNIs and residual muscles was used to decode finger and grasp movements. Though signal amplitude varied between sessions, P2 maintained real-time prosthetic performance above 94% accuracy for 604 d without recalibration. Additionally, P2 completed a real-world multi-sequence coffee task with 99% accuracy for 611 d without recalibration.Significance.This study demonstrates the potential of RPNIs and implanted EMG electrodes as a long-term interface for enhanced prosthetic control.

Quality of Life in People With Unilateral Lower Limb Amputation at a Tertiary Rehabilitation Centre in Northern India: A Cross-Sectional Study

Background and purpose The patients after amputation undergo a sudden transformation in their quality of life. In India, amputation done at the appropriate time is a rare phenomenon because usually, the patients present themselves at the later stages. The surgeons, however, while performing amputation surgeries, primarily consider saving the life of a patient under adverse conditions when patients report to them very late that the surgeries are carried out urgently. Assessing the quality of life (QOL) and the various sociodemographic factors affecting the QOL paves the way for future rehabilitation programs. Aims and objectives To evaluate the quality of life of subjects with unilateral lower limb amputation among the North Indian population. Materials and methods This cross-sectional study was conducted in the tertiary rehabilitation center. A total of 106 Subjects were recruited. Informed consent was taken. WHOQOL-BREF contains 26 items covering four important aspects of QOL. The WHOQOL-BREF self-administered free questionnaire was used as a data collection tool, and the Hindi version downloaded from the WHO website was also used for those who can't understand English. Results The range of the physical domain, psychological domain, social domain, and environmental domain were 0 and 100. The mean score of different QOL transformed domain scores (on a scale of 100) were 47.91±20.12, 57.37±20.46, 59.36±25.32 and 51.50±21.96, respectively. Trauma was the leading cause of amputation, followed by diabetes mellitus, cancer, peripheral vascular disease, and other causes. Transtibial amputees were more in number compared to transfemoral. The percentage of male and female amputees was 78.30%, and 21.70%, respectively. Conclusion The physical domain was the most affected domain, followed by the psychological, social, and environmental domains. A delay in the prosthesis fitment aggravates the physical burden of amputees. Early prosthesis & psychological counseling will improve the QOL significantly.

Prosthesis use among individuals with lower limb amputation in Bangladesh

OBJECTIVE

This study aimed to assess factors related to prostheses use among individuals with lower limb amputation in Bangladesh.

METHODS

Data related to prosthesis use, functional capabilities (as measured with the Locomotor Capabilities Index [LCI]), and user satisfaction were collected using telephone interviews between January 2014 and October 2016. Descriptive and regression analyses were performed.

RESULTS

This study involved 183 participants (89.6% male); the mean (SD) age was 49.5 (10.7) years. Most of the participants (95.6%) used prostheses daily, and the mean (SD) duration of use was 7.0 (4.1) hours per day. The mean (SD) basic LCI score, advanced LCI score, and total LCI score were 25.1 (4.9), 20.8 (8.3), and 45.9 (12.2), respectively. Among them, 36.7% were dissatisfied with the weight of the prosthesis. Having a below knee amputation (odds ratio 2.6 and confidence interval 1.3, 5.3) and absence of comorbidities (odds ratio 2.1; confidence interval 1.0, 4.4) were associated significantly with an increased use of prosthesis.

CONCLUSION

Factors such as weight of the prosthesis, amputation level, and presence of comorbidities are important considerations while planning for prosthetic rehabilitation and optimize utilization of the prosthetic devices.

Prosthesis preferences for those with upper limb loss: Discrete choice study of PULLTY® for use in regulatory decisions

Introduction

The patient's voice in shared decision-making has progressed from physician's office to regulatory decision-making for medical devices with FDA's Patient Preference Initiative. A discrete-choice preference measure for upper limb prosthetic devices was developed to investigate patient's risk/benefit preference choices for regulatory decision making.

Methods

Rapid ethnographic procedures were used to design a discrete-choice measure describing risk and benefits of osseointegration with myoelectric control and test in a pilot preference study in adults with upper limb loss. Primary outcome is utility of each choice based conjoint (CBC) attribute using mixed-effects regression. Utilities with and without video, and between genders were compared.

Results

Strongest negative preference was for avoiding infection risk (B = -1.77, p < 0.001) and chance of daily pain (B = -1.22, p, 0.001). Strongest positive preference was for attaining complete independence when cooking dinner (B = 1.62, p < 0.001) and smooth grip patterns at all levels (B = 1.62, B = 1.28, B = 1.26, p < 0.001). Trade-offs showed a 1% increase in risk of serious/treatable infection resulted in a 1.77 decrease in relative preference. There were gender differences, and where video was used, preferences were stronger.

Conclusions

Strongest preferences were for attributes of functionality and independence versus connectedness and sensation but showed willingness to make risk-benefit trade-offs. Findings provide valuable information for regulatory benefit-risk decisions for prosthetic device innovations.

Trial Registration

This study is not a clinical trial reporting results of a health care intervention so is not registered.

Embodiment for Robotic Lower-Limb Exoskeletons: A Narrative Review

Research on embodiment of objects external to the human body has revealed important information about how the human nervous system interacts with robotic lower limb exoskeletons. Typical robotic exoskeleton control approaches view the controllers as an external agent intending to move in coordination with the human. However, principles of embodiment suggest that the exoskeleton controller should ideally coordinate with the human such that the nervous system can adequately model the input-output dynamics of the exoskeleton controller. Measuring embodiment of exoskeletons should be a necessary step in the exoskeleton development and prototyping process. Researchers need to establish high fidelity quantitative measures of embodiment, rather than relying on current qualitative survey measures. Mobile brain imaging techniques, such as high-density electroencephalography, is likely to provide a deeper understanding of embodiment during human-machine interactions and advance exoskeleton research and development. In this review we show why future exoskeleton research should include quantitative measures of embodiment as a metric of success.

Measuring Satisfaction With Upper Limb Prostheses: Orthotics and Prosthetics User Survey Revision That Includes Issues of Concern to Women

OBJECTIVE

To (1) modify the Orthotics and Prosthetics User Survey (OPUS) Client Satisfaction with Device (CSD) instrument to incorporate issues of concern to women and (2) evaluate measure's structural and concurrent validity and reliability in persons with upper limb amputation (ULA).

DESIGN

Cross-sectional survey study with retest after 2 weeks. Exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and Rasch analyses were used to select items and examine differential item functioning, range of coverage, and person and item reliability. Test-retest reliability was evaluated with intraclass correlation coefficients. Pearson correlations were used to estimate associations with other prosthesis satisfaction measures.

SETTING

Telephone administered survey.

PARTICIPANTS

Convenience sample of 468 participants in the US (N=468; 19.9% women) with ULA, including a 50-person retest subsample (4% female).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Modified OPUS CSD.

RESULTS

EFA suggested 3 subscales: Comfort, Appearance, and Utility. CFA found acceptable model fit. After dropping items with poor fit and high pairwise correlations in Rasch partial credit models, CFA model fit indices were acceptable (comparative fit index=0.959, Tucker-Lewis Index=0.954, root mean square error of approximation=0.082). Rasch person reliability was 0.62 (Utility), 0.77 (Appearance), and 0.82 (Comfort). Cronbach α was 0.81, 87, and 0.71 for Comfort and Appearance, and Utility subscales, respectively. Correlations between the modified CSD, the original CSD, and the Trinity Amputation and Prosthesis Experience Satisfaction Scale were 0.54-0.94.

CONCLUSIONS

We identified 3 subscales: Comfort (6 items), Appearance (8 items), and Utility (4 items) with 7 new items identified as important to women. The subscales demonstrate evidence of sound concurrent structural and test-retest reliability and concurrent validity. The Appearance and Comfort subscales have good reliability for group-level use in clinical and research applications, whereas the Utility subscale had poor to fair person reliability but excellent item reliability.

Prospective pre-operative 3-T MR neurography peripheral nerve mapping of upper extremity amputations implanted with FAST-LIFE electrode interfaces of robotic hands: technical report

BACKGROUND AND PURPOSE

Fascicular targeting of longitudinal intrafascicular electrode (FAST-LIFE) interface enables hand dexterity with exogenous electrical microstimulation for sensory restoration, custom neural recording hardware, and deep learning-based artificial intelligence for motor intent decoding. The purpose of this technical report from a prospective pilot study was to illustrate magnetic resonance neurography (MRN) mapping of hand and nerve anatomy in amputees and incremental value of MRN over electrophysiology findings in pre-surgical planning of FAST-LIFE interface (robotic hand) patients.

MATERIALS AND METHODS

After obtaining informed consent, patients with upper extremity amputations underwent pre-operative 3-T MRN, X-rays, and electrophysiology. MRN findings were correlated with electrophysiology reports. Descriptive statistics were performed.

RESULTS

Five patients of ages 21-59 years exhibited 3/5 partial hand amputations, and 2/5 transradial amputations on X-rays. The median and ulnar nerve end bulb neuromas measured 10.1 ± 3.04 mm (range: 5.5-14 mm, median: 10.5 mm) and 10.9 ± 7.64 mm (2-22 mm, 9.75 mm), respectively. The ADC of median and ulnar nerves were increased at 1.64 ± 0.1 × 10^-3 mm²/s (range: 1.5-1.8, median: 1.64 × 10^-3 mm²/s) and 1.70 ± 0.17 × 10^-3 mm²/s (1.49-1.98 × 10^-3 mm²/s, 1.65 × 10^-3 mm²/s), respectively. Other identified lesions were neuromas of superficial branch of the radial nerve and anterior interosseous nerve. On electrophysiology, 2/5 reports were unremarkable, 2/5 showed mixed motor-sensory neuropathies of median and ulnar nerves along with radial sensory neuropathy, and 1/5 showed sensory neuropathy of lateral cutaneous nerve of the forearm. All patients regained naturalistic sensations and motor control of digits.

CONCLUSION

3-T MRN allows excellent demonstration of forearm and hand nerve anatomy, altered diffusion characteristics, and their neuromas despite unremarkable electrophysiology for pre-surgical planning of the FAST-LIFE (robotic hand) interfaces.

Mobility Analysis of AmpuTees (MAAT 7): Normative Mobility Values for Lower Limb Prosthesis Users of Varying Age, Etiology, and Amputation Level

OBJECTIVE

The aim of the study was to establish normative values of lower limb amputation mobility across primary etiologies based on age and amputation level.

DESIGN

This study is a cross-sectional observational analysis of outcomes. A total of 11,995 lower limb prosthesis users were included in the analysis. Participants were grouped by etiology into four categories: cancer, congenital, trauma, and diabetes/dysvascular. Mobility was assessed by using the Prosthetic Limb Users Survey of Mobility.

RESULTS

Mobility across seven age groups for the four etiologies was established for both above-the-knee amputation and below-the-knee amputation. Differences were found between age groups for individuals: above-the-knee amputation: cancer (χ 2 (6) = 40.97, P < 0.001), congenital (χ 2 (3) = 9.41, P = 0.024), trauma (χ 2 (6) = 18.89, P = 0.004), and dysvascular (χ 2 (5) = 39.73, P < 0.001; below-the-knee amputation: cancer (χ 2 (6) = 29.77, P < 0.001), trauma (χ 2 (6) = 28.22, P < 0.001), and dysvascular (χ 2 (6) = 144.66, P < 0.001).

CONCLUSIONS

The awareness of differences across amputation etiologies extending across the lifespan of ages can assist the goal-setting process as part of prosthetic rehabilitation. In addition, refined normative values provide the ability to benchmark new and innovative changes in clinical practice.

Testing Precision and Accuracy of an Upper Extremity Proprioceptive Targeting Task Assessment

Objective

To develop and test an assessment measuring extended physiological proprioception (EPP). EPP is a learned skill that allows one to extend proprioception to an external tool, which is important for controlling prosthetic devices. The current study examines the ability of this assessment to measure EPP in a nonamputee population for translation into the affected population.

Design

Measuring precision and accuracy of an upper extremity (UE) proprioceptive targeting task assessment. Participants completed 2 sessions of a targeting task while seated at a table. The targeting was completed with the dominant and nondominant hand and with eyes open and eyes closed during the task. Participants completed 2 sessions of the clinical test with a 1-week washout period to simulate reasonable time between clinical visits.

Setting

Research laboratory.

Participants

Twenty right-handed participants (N=20) with no neurologic or orthopedic deficits that would interfere with proprioception, median age of 25 years (range, 19-33 years), completed the assessment (10 men, 10 women).

Interventions

Not applicable.

Main Outcome Measures

Precision (consistency in targeting) and accuracy (distance between the intended target and participant result) in UE targeting task using EPP; test-retest repeatability between sessions.

Results

Both precision and accuracy were significantly decreased in the eyes-closed condition compared with the eyes-open condition regardless of targeting with dominant or nondominant hand (all P<.001). In the eyes-open condition, there was a dominance effect relating to the accuracy; however, in the eyes-closed condition, accuracy between dominant and nondominant hands was statistically equivalent. Based on minimum detectable change with 95% confidence, there was no change in either metric between the first and second sessions.

Conclusions

The results of this study support the feasibility of using this assessment to measure EPP-based on the definition of EPP as a learned skill that indicates control over an external, simple tool-because they demonstrate reliance on proprioception in the eyes-closed condition, symmetry in proprioceptive accuracy between hands for within-participant control, and test-retest reliability for longitudinal measurements. The results also establish normative values for this assessment in young, healthy adults. Further research is required in a clinical population to evaluate the UE proprioceptive targeting task assessment further and collect objective data on EPP.

Factors Related to Neuropathic Pain following Lower Extremity Amputation

BACKGROUND

Lower extremity amputations are common, and postoperative neuropathic pain (phantom limb pain or symptomatic neuroma) is frequently reported. The use of active treatment of the nerve end has been shown to reduce pain but requires additional resources and should therefore be performed primarily in high-risk patients. The aim of this study was to identify the factors associated with the development of neuropathic pain following above-the-knee amputation, knee disarticulation, or below-the-knee amputation.

METHODS

Retrospectively, 1565 patients with an average follow-up of 4.3 years who underwent a primary above-the-knee amputation, knee disarticulation, or below-the-knee amputation were identified. Amputation levels for above-the-knee amputations and knee disarticulations were combined as proximal amputation level, with below-the-knee amputations being performed in 61 percent of patients. The primary outcome was neuropathic pain (i.e., phantom limb pain or symptomatic neuroma) based on medical chart review. Multivariable logistic regression was performed to identify independent factors associated with neuropathic pain.

RESULTS

Postoperative neuropathic pain was present in 584 patients (37 percent), with phantom limb pain occurring in 34 percent of patients and symptomatic neuromas occurring in 3.8 percent of patients. Proximal amputation level, normal creatinine levels, and a history of psychiatric disease were associated with neuropathic pain. Diabetes, hypothyroidism, and older age were associated with lower odds of developing neuropathic pain.

CONCLUSIONS

Neuropathic pain following lower extremity amputation is common. Factors influencing nerve regeneration, either increasing (proximal amputations and younger age) or decreasing (diabetes, hypothyroidism, and chronic kidney disease) it, play a role in the development of postamputation neuropathic pain.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Targeted Muscle Reinnervation for Trauma-Related Amputees: A Systematic Review

While amputation techniques have improved over time, questions remain around how to best treat neuromas and severed nerves in the amputee population, specifically for trauma-related amputees. This systematic review investigates and summarizes outcomes following targeted muscle reinnervation (TMR) for the trauma-related amputee population. Studies were classified based on primary or secondary TMR and relevant outcomes, including the ability to use a prosthesis, post-TMR opioid use, Patient-Reported Outcomes Measurement Information System (PROMIS) scores for phantom limb pain and residual limb pain, and overall pain resolution/reduction. Following TMR for trauma-related amputation, most patients experienced neuroma pain resolution (86.2%, 95% confidence interval [CI]: 67.2-95.0%) and overall pain reduction/resolution (90.7%, 95% CI: 82.2-95.4%). No differences were seen between primary and secondary TMR. Preliminary evidence indicates that TMR is effective for preventing or treating pain in patients with trauma-related amputation, whether used in the acute or delayed setting.

The use of myoelectric prosthesis in a sample of veterans with unilateral upper extremity amputation: prosthesis satisfaction and quality of life

AIMS

To determine the relationship between clinic and prosthesis-related characteristics and psychosocial adjustment, activity restriction, satisfaction with the prosthesis and quality of life in myoelectric prosthesis users with upper limb amputation.

METHODS

Thirty patients with myoelectric prosthesis users with upper limb amputation took part in this study. The patients' demographic and clinical information were recorded. Psychosocial adjustment, activity restriction and satisfaction with the prosthesis were assessed with Trinity Amputation and Prosthesis Experience Scales-Revised (TAPES-R). Short-Form 36 (SF-36) was used for the quality of life.

RESULTS

TAPES-R activity restriction score was significantly higher in patients with transhumeral or elbow disarticulation and with concomitant lower limb amputation (p = 0.009, p = 0.037, respectively). TAPES-R psychosocial adjustment subparameter score had significantly moderate correlation with daily prosthesis wearing time (p = 0.019 r = 0.425). A significant negative correlation was found between age at the time of the injury and SF-36 role limitation due to physical problem (p = 0.028 r = - 0.401).

CONCLUSIONS

Clarifying the factors related to psychosocial adjustment, activity restriction, prosthesis satisfaction and quality of life in individuals with upper extremity amputation and producing interventions/approaches that support patients' life are meaningful and important steps.

CLINICAL TRIAL REGISTER

E2-22-1416.

Psychometric evaluation of the Arabic version of the Quebec user evaluation of satisfaction with assistive technology (A-QUEST 2.0) in prosthesis users

BACKGROUND

The evaluation of patient satisfaction and perceptions plays a vital role in determining the quality of prosthesis users' devices and the competency of healthcare services.

AIM

To evaluate the psychometric properties of the Arabic Quebec User Evaluation of Satisfaction with Assistive Technology (A-QUEST 2.0) with prosthetics users.

DESIGN

A methodological study.

SETTING

Saudi Arabia, Turkey.

POPULATION

A convenience sample of outpatient prosthesis users (N.=183).

METHODS

The A-QUEST 2.0 includes two subscales respectively evaluating the user's satisfaction with the device and the services provided. The data for each subscale were investigated using Rasch analysis to evaluate the item fit, reliability indices, item difficulty, local item dependency, and differential item functioning (DIF).

RESULTS

Both subscales met the Rasch criteria for the functioning of rating scale categories. All items showed an acceptable fit to the Rasch model. The person separation indices for the Device and Services subscales were 2.21 (Cronbach's α=0.90) and 1.72 (Cronbach's α=0.85), respectively. Therefore, the two subscales are sensitive enough to distinguish between at least three different levels of satisfaction. The unidimensionality of each subscale was confirmed, and none of the items displayed differential item functioning across age, gender, location of amputation, country, and duration of use.

CONCLUSIONS

Overall, the findings indicate the psychometric evaluation of A-QUEST 2.0 is effective with prosthesis users across different clinical contexts and cultures. Thus, the A-QUEST 2.0 allows for a comprehensive understanding of users' perceptions of prosthesis characteristics, particularly among subjects with lower limb amputations caused by traumatic injuries.

CLINICAL REHABILITATION IMPACT

Our paper provides clinicians dealing with Arabic patients a validated outcome measure for satisfaction with prosthesis. Besides providing information in the development of new products and service delivery. Further studies are necessary to improve the measure's metric quality in different contexts and for different prosthesis devices.

Factors related to indoor prosthetic use in individuals with unilateral lower limb amputation

BACKGROUND

The rate of indoor prosthetic use in people with lower limb amputation (LLA) is lower than that of outdoor use. Very few studies of indoor prosthetic use have been conducted, and no studies have focused on the perspective of instrumental activities of daily living (IADLs).

OBJECTIVES

To assess the indoor prosthetic use of individuals with unilateral LLA from the perspective of IADLs.

STUDY DESIGN

Cross-sectional study.

METHODS

A total of 162 people with LLA participated in this study. Based on the information obtained from a questionnaire and medical records, the relationships between each outcome and indoor prosthetic use were assessed by univariate analysis and multivariate logistic regression analysis.

RESULTS

Of the 110 respondents (72.8%), 6 participants did not use the prosthesis or used it for cosmesis. With respect to the prosthetic users (n = 104), 74 (71.2%) used their prosthesis indoors and outdoors and 30 (28.8%) used it only outdoors, but none used it indoors only. On univariate analysis, five items were identified: household size, amputation level, domestic chores and outdoor activities of the Frenchay Activities Index, and difficulty donning/doffing the prosthesis. Small household, transtibial amputation, and a high score on the domestic chores of the Frenchay Activities Index (cutoff value 9.0 points) were independently associated with indoor prosthetic use.

CONCLUSIONS

Training of motions that are desirable to use the prosthesis and participation in domestic chores frequently based on IADLs before hospitalization may increase the frequency of prosthesis use in people with transfemoral amputation who use their prosthesis outdoors.

Amputee, clinician, and regulator perspectives on current and prospective upper extremity prosthetic technologies

Existing prosthetic technologies for people with upper limb amputation are being adopted at moderate rates. Once fitted for these devices, many upper limb amputees report not using them regularly or at all. The primary aim of this study was to solicit feedback about prosthetic technology and important device design criteria from amputees, clinicians, and device regulators. We compare these perspectives to identify common or divergent priorities. Twenty-one adults with upper limb loss, 35 clinicians, and 3 regulators completed a survey on existing prosthetic technologies and a conceptual sensorimotor prosthesis driven by implanted myoelectric electrodes with sensory feedback via spinal root stimulation. The survey included questions from the Trinity Amputation and Prosthesis Experience Scale, the Disabilities of the Arm, Shoulder, and Hand, and novel questions about technology acceptance and neuroprosthetic design. User and clinician ratings of satisfaction with existing devices were similar. Amputees were most accepting of the proposed sensorimotor prosthesis (75.5% vs clinicians(68.8%), regulators(67.8%)). Stakeholders valued user-centered outcomes like individualized task goals, improved quality of life, device reliability, and user safety; regulators emphasized these last two. The results of this study provide insight into amputee, clinician, and regulator priorities to inform future upper-limb prosthetic design and clinical trial protocol development.

Challenges and Potential in Targeted Muscle Reinnervation in Pediatric Amputees

Targeted muscle reinnervation (TMR) is a powerful new tool in preventing and treating residual limb and phantom limb pain. In the adult population, TMR is rapidly becoming standard of care; however, there is a paucity of literature regarding indications and outcomes of TMR in the pediatric population. We present 2 cases of pediatric patients who sustained amputations and the relevant challenges associated with TMR in their cases. One is a 7-year-old patient who developed severe phantom and residual limb pain after a posttraumatic above-knee amputation. He failed pharmacologic measures and underwent TMR. He obtained complete relief of his symptoms and is continuing to do well 1.5 years postoperatively. The other is a 2-year-old boy with bilateral wrist and below-knee amputations as sequelae of sepsis. TMR was not performed because the patient never demonstrated evidence of phantom limb pain or symptomatic neuroma formation. We use these 2 cases to explore the challenges particular to pediatric patients when considering treatment with TMR, including capacity to report pain, risks of anesthesia, and cortical plasticity. These issues will be critical in determining how TMR will be applied to pediatric patients.

Do chronic pain syndromes in lower limb amputees have an effect on the use of prostheses?

BACKGROUND

The use of a prosthesis is critical to regain the ability to walk in lower limb amputees but the relationship between the use of a prosthesis and chronic pain syndromes (PLS, PLP, RLP), common in amputees patients, is still poorly understood.

OBJECTIVE

This long-term follow-up study investigates the possible correlation between prosthesis use and the presence of PLP, PLS and RLP in lower limb amputees.

METHODS

Patients undergoing transtibial, transfemoral or hemipelvectomy amputation of any aetiology at the Rizzoli Orthopaedic Institute from 2008 to 2018 were included. The Houghton scale was used to assess functional use of the prosthesis.

RESULTS

The results show that, in lower limb amputees, prosthesis use is greater in individuals with below-the-knee amputation and in those who were younger at the time of amputation. No significant correlation between the presence of pain syndromes (PLS, PLP, RLP) and the various items on the Houghton scale was found.

CONCLUSIONS

The study found no significant correlation indicating that phantom limb pain syndromes affect amputee use of a prosthesis.

A non-invasive wearable sensory leg neuroprosthesis: mechanical, electrical and functional validation

OBJECTIVE

Lower limb amputees suffer from a variety of functional deficits related to the absence of sensory communication between the central nervous system and the lost extremity. Indeed, they experience high risk of falls, asymmetric walking and balance, and low prosthesis embodiment, that significantly decrease their quality of life. Presently, there are no commercially available devices able to provide sensory feedback to leg amputees. Recently, some invasive solutions (i.e. requiring a surgery) have been proposed by different research groups, however a non-invasive effective alternative exploitable in everyday life is still missing.

APPROACH

To address this need we developed and tested a lightweight, non-invasive, wearable technology (NeuroLegs) providing sensory (i.e. knee angle joint and tactile) feedback to the users through electro-cutaneous stimulation. A user-friendly GUI and mobile App have been developed to easily calibrate and control the system. Standard mechanical and electrical tests were performed to assess the safety and reliability of the technology.

MAIN RESULTS

No mechanical failures, stable communication among system parts and a long-lasting battery (>23h) were demonstrated. The NeuroLegs system was then verified in terms of accuracy in measuring relevant gait parameters in healthy participants. A high temporal reliability was found when detecting stride features (important for the real-time configuration) with a correct match to the walking cadence, in all assessed walking conditions. The effectiveness of the NeuroLegs system at improving walking of three transfemoral amputees was then verified in movement laboratory tests. Increased temporal gait symmetry and augmented confidence were found. Stepping outside from the lab, Neurolegs was successfully exploited by a transfemoral amputee in CYBATHLON Global Edition 2020 in several challenging situations related to daily-living activities.

SIGNIFICANCE

Our results demonstrate that the NeuroLegs system provides the user with useful sensory information that can be successfully exploited in different walking conditions of daily life.

Questioning Domain Adaptation in Myoelectric Hand Prostheses Control: An Inter- and Intra-Subject Study

One major challenge limiting the use of dexterous robotic hand prostheses controlled via electromyography and pattern recognition relates to the important efforts required to train complex models from scratch. To overcome this problem, several studies in recent years proposed to use transfer learning, combining pre-trained models (obtained from prior subjects) with training sessions performed on a specific user. Although a few promising results were reported in the past, it was recently shown that the use of conventional transfer learning algorithms does not increase performance if proper hyperparameter optimization is performed on the standard approach that does not exploit transfer learning. The objective of this paper is to introduce novel analyses on this topic by using a random forest classifier without hyperparameter optimization and to extend them with experiments performed on data recorded from the same patient, but in different data acquisition sessions. Two domain adaptation techniques were tested on the random forest classifier, allowing us to conduct experiments on healthy subjects and amputees. Differently from several previous papers, our results show that there are no appreciable improvements in terms of accuracy, regardless of the transfer learning techniques tested. The lack of adaptive learning is also demonstrated for the first time in an intra-subject experimental setting when using as a source ten data acquisitions recorded from the same subject but on five different days.