Prosthetic outcomes after amputation and the impact of mobility level on survival.

OBJECTIVE: Lower extremity amputation continues to be necessary in a significant number of patients with peripheral vascular disease. The 5-year survival following lower limb loss is markedly reduced. Many of these patients are never fitted with a prosthesis, and there is a dearth of knowledge regarding the barriers to prosthetic attainment. The goal of this study was to identify the risk factors for not receiving a prosthesis and the effect of mobility level on survival following major amputation. METHODS: This was a retrospective analysis of all patients that underwent lower extremity amputation by surgeons in our practice from January 1, 2010, to December 31, 2019. Abstracted data included: age, sex, race, body mass index, comorbidities, American Society of Anesthesiologists score, statin use, level of amputation, stump revision, fitting for prosthesis, type of prosthesis, and the United States' Medicare Functional Classification Level, also called K level. Survival was determined using a combination of sources, including the Social Security Death Master File, searches of multiple genealogic registries, and general internet searches. Multivariable logistic regression was used to determine risk factors associated with prosthesis attainment. Multivariable Cox proportional hazard regression with time-dependent covariates was performed to assess risk factors associated with 5-year mortality. RESULTS: A total of 464 patients were included in this study. The mean age was 65 years, and mean body mass index was 27 kg/m2. The majority of patients were male (68%), White (56%), diabetic (62%), and hypertensive (76%), and underwent below-the-knee amputation (69%). Prosthetic attainment occurred in 185 (40%). On multivariable analysis, age >81 years and current tobacco use were associated with no prosthetic fitting. Overall 5-year survival was 41.9% (95% confidence interval [CI], 37.6%-46.6%) (below-the-knee amputation, 47.7% [95% CI, 42.5%-53.5%]; above-the-knee amputation, 28.7% [95% CI, 22.1%-37.2%]). On multivariable analysis, age >60 years, congestive heart failure, above-the-knee amputation, and no prosthetic attainment were associated with decreased survival. Increasing K level was incrementally associated with improved survival. CONCLUSIONS: This study has identified several patient factors associated with prosthetic attainment, as well as multiple factors predictive of reduced survival after amputation. Being referred for prosthetic fitting was associated with improved survival not explained by patient characteristics and comorbidities. The Medicare Functional Classification Level K level predicts survival. More research is needed to determine the barriers to prosthetic attainment and if improving a patients K level will improve survival.

Using mobile eye tracking to measure cognitive load through gaze behavior during walking in lower limb prosthesis users: A preliminary assessment.

BACKGROUND: Lower limb amputation does not affect only physical and psychological functioning but the use of a prosthetic device can also lead to increased cognitive demands. Measuring cognitive load objectively is challenging, and therefore, most studies use questionnaires that are easy to apply but can suffer from subjective bias. Motivated by this, the present study investigated whether a mobile eye tracker can be used to objectively measure cognitive load by monitoring gaze behavior during a set of motor tasks. METHODS: Five prosthetic users and eight able-bodied controls participated in this study. Eye tracking data and kinematics were recorded during a set of motor tasks (level ground walking, walking on uneven terrain, obstacle avoidance, stairs up and ramp down, as well as ramp up and stairs down) while the participants were asked to focus their gaze on a visual target for as long as possible. Target fixation times and increase in pupil diameters were determined and correlated to subjective ratings of cognitive load. FINDINGS: Overall, target fixation time and pupil diameter showed strong negative and positive correlations, respectively, to the subjective rating of cognitive load in the able-bodied controls (-0.75 and 0.80, respectively). However, the individual correlation strength, and in some cases, even the sign, was different across participants. A similar trend could be observed in prosthetic users. INTERPRETATION: The results of this study showed that a mobile eye tracker may be used to estimate cognitive load in prosthesis users during locomotor tasks. This paves the way to establish a new approach to assessing cognitive load, which is objective and yet practical and simple to administer. Nevertheless, future studies should corroborate these results by comparing them to other objective measures as well as focus on translating the proposed approach outside of a laboratory.

Assessment of 3D printed mechanical metamaterials for prosthetic liners.

This study focuses on novel design and evaluation of Elastic 50A (EL50) mechanical metamaterials with open-cell patterns for its potential application to lower limb residuum/socket interfaces, specifically that of a transtibial (TT) amputee. Mechanical characteristics, that is, effective Young's modulus (E), was tuned by altering metamaterial porosity, which was experimentally verified. Specifically, pore radius of the unit cell was varied to achieve a range of E-values (0.05-1.71 MPa) for these 3D printed metamaterials. Finite Element Analysis (FEA) was conducted to evaluate pressure distribution across key load-bearing anatomical sites of a TT residuum. Using designed metamaterials for homogeneous liners, pressure profiles were studied and compared with a silicone liner case. Additionally, a custom metamaterial liner was designed by assigning appropriate metamaterials to four load-sensitive and tolerant anatomical sites of the TT residuum. The results suggest that lowest pressure variation (PV), as a measure of pressure distribution levels and potential comfort for amputees, was achieved by the custom metamaterial liner compared to any of the homogeneous liners included in this study. It is envisaged that this work may aid future design and development of custom liners using now commonly available 3D printing technologies and available elastomer materials to maximise comfort, tissue safety and overall rehabilitation outcomes for lower limb amputees.

Transfemoral limb loss modestly increases the metabolic cost of optimal control simulations of walking.

Background: In transtibial limb loss, computer simulations suggest that the maintenance of muscle strength between pre- and post-limb loss can maintain the pre-limb loss metabolic cost. These results are consistent with comparable costs found experimentally in select cases of high functioning military service members with transtibial limb loss. It is unlikely that similar results would be found with transfemoral limb loss, although the theoretical limits are not known. Here we performed optimal control simulations of walking with and without an above-knee prosthesis to determine if transfemoral limb loss per se increases the metabolic cost of walking. Methods: OpenSim Moco was used to generate optimal control simulations of walking in 15 virtual "subjects" that minimized the weighted sum of (i) deviations from average able-bodied gait mechanics and (ii) the gross metabolic cost of walking, pre-limb loss in models with two intact biological limbs, and post-limb loss with one of the limbs replaced by a prosthetic knee and foot. No other changes were made to the model. Metabolic cost was compared between pre- and post-limb loss simulations in paired t-tests. Results: Metabolic cost post-limb loss increased by 0.7-9.3% (p < 0.01) depending on whether cost was scaled by total body mass or biological body mass and on whether the prosthetic knee was passive or non-passive. Conclusions: Given that the post-limb loss model had numerous features that predisposed it to low metabolic cost, these results suggest transfemoral limb loss per se increases the metabolic cost of walking. However, the large differences above able-bodied peers of ∼20-45% in most gait analysis experiments may be avoidable, even when minimizing deviations from able-bodied gait mechanics. Portions of this text were previously published as part of a preprint (https://www.biorxiv.org/content/10.1101/2023.06.26.546515v2.full.pdf).

Efficacy of rehabilitation after provision of ICRC lower limb prostheses in low-income and middle-income countries: A quantitative assessment from Myanmar.

BACKGROUND: Low-income and middle-income countries (LMICs) have poorly resourced health services. Lack of access to assistive devices, such as prosthetics, may limit the functional outcomes of persons with amputation and affect quality of life (QoL). OBJECTIVE: The objective of this study was to assess the functional level and QoL of prosthetic users in LMICs when prescribed a prosthesis made from International Committee for Red Cross (ICRC) components. STUDY DESIGN: The study design included a quantitative descriptive methodology assessing functional outcomes and QoL after prosthetic provision. METHODS: Participants were identified from the prosthetic service in Mandalay, Myanmar. Included participants were those with unilateral, traumatic, lower limb amputations, with ICRC devices delivered at least 6 months earlier. Participants attended the prosthetic service and were assessed using the Amputee Mobility Predictor with Prosthesis tool and the World Health Organization Quality of Life Brief and Disability modules. RESULTS: Thirty-five participants completed the study; of them, 63% were persons with transtibial level amputation and 37% were with transfemoral level amputation. Approximately 83% achieved a score of more than 37 using the Amputee Mobility Predictor with Prosthesis. There is a strong positive correlation between QoL and physical health (r = 0.55; p < 0.001), social relationships (r = 0.66; p < 0.001), and inclusion (r = 0.53; p < 0.001). Participants had a better QoL and overall health when they had better psychological health. CONCLUSION: The patient-based results presented within this study could be considered as a contribution to the evidence base and importance of provision of prosthetic services in LMICs. It was observed that participants with an amputation were able to achieve a high level of physical function with the ICRC prostheses while also reporting a high QoL.

Association of Race, Ethnicity, and Gender to Disparities in Functional Recovery and Social Health After Major Lower Limb Amputation: A Cross-sectional Pilot Study.

OBJECTIVE: To assess if evidence of disparities exists in functional recovery and social health post-lower limb amputation. DESIGN: Race-ethnicity, gender, and income-based group comparisons of functioning and social health in a convenience sample of lower limb prosthetic users. SETTING: Prosthetic clinics in 4 states. PARTICIPANTS: A geographically diverse cohort of 56 English and Spanish speaking community-dwelling individuals with dysvascular lower limb amputation, between 18-80 years old. INTERVENTIONS: None. MAIN OUTCOMES MEASURES: Primary outcomes included 2 physical performance measures, the Timed Up and Go test and 2-minute walk test, and thirdly, the Prosthetic Limb Users Survey of Mobility. The PROMIS Ability to Participate in Social Roles and Activities survey measured social health. RESULTS: Of the study participants, 45% identified as persons of color, and 39% were women (mean ± SD age, 61.6 (9.8) years). People identifying as non-Hispanic White men exhibited better physical performance than men of color, White women, and women of color by -7.86 (95% CI, -16.26 to 0.53, P=.07), -10.34 (95% CI, -19.23 to -1.45, P=.02), and -11.63 (95% CI, -21.61 to -1.66, P=.02) seconds, respectively, on the TUG, and by 22.6 (95% CI, -2.31 to 47.50, P=.09), 38.92 (95% CI, 12.53 to 65.30, P<.01), 47.53 (95% CI, 17.93 to 77.13, P<.01) meters, respectively, on the 2-minute walk test. Income level explained 14% and 11% of the variance in perceived mobility and social health measures, respectively. CONCLUSIONS: Study results suggest that sociodemographic factors of race-ethnicity, gender, and income level are associated with functioning and social health post-lower limb amputation. The clinical effect of this new knowledge lies in what it offers to health care practitioners who treat this patient population, in recognizing potential barriers to optimal recovery and quality of life. More work is required to assess lived experiences after amputation and provide better understanding of amputation-related health disparities.

Out-of-pocket costs and affordability of upper limb prostheses.

BACKGROUND: Given the funding policies in the Department of Veterans Affairs, the affordability of prostheses may be less of a concern among Veterans as compared to civilians. OBJECTIVES: Compare rates of out-of-pocket prosthesis-related payments for Veterans and non-Veterans with upper limb amputation (ULA), develop and validate a measure of prosthesis affordability, and evaluate the impact of affordability on prosthesis nonuse. STUDY DESIGN: Telephone survey of 727 persons with ULA; 76% Veterans and 24% non-Veterans. METHODS: Odds of paying out-of-pocket costs for Veterans compared with non-Veterans were computed using logistic regression. Cognitive and pilot testing resulted in a new scale, evaluated using confirmatory factor and Rasch analysis. Proportions of respondents who cited affordability as a reason for never using or abandoning a prosthesis were calculated. RESULTS: Twenty percent of those who ever used a prosthesis paid out-of-pocket costs. Veterans had 0.20 odds (95% confidence interval, 0.14-0.30) of paying out-of-pocket costs compared with non-Veterans. Confirmatory factor analysis supported unidimensionality of the 4-item Prosthesis Affordability scale. Rasch person reliability was 0.78. Cronbach alpha was 0.87. Overall, 14% of prosthesis never-users said affordability was a reason for nonuse; 9.6% and 16.5% of former prosthesis users said affordability of repairs or replacement, respectively, was a reason for abandonment. CONCLUSIONS: Out-of-pocket prosthesis costs were paid by 20% of those sample, with Veterans less likely to incur costs. The Prosthesis Affordability scale developed in this study was reliable and valid for persons with ULA. Prosthesis affordability was a common reason for never using or abandoning prostheses.

Model Predictions that Consider Individualized Gait Patterns and Patient Mobility Level for the Use of Passive Hip-Flexion Exosuits by Persons with Unilateral Transfemoral Amputation.

The muscular remodeling that occurs during a transfemoral amputation surgery and subsequent long-term use of mechanically-passive prostheses have significant impacts on the mobility and gait pattern of the patient. At toe-off and during the subsequent swing phase, this behavior is characterized by increased hip flexion moment and power provided by the biological limb. In other patient populations (e.g., individuals with multiple sclerosis) passive tension-generating assistive elements have been shown to restore altered hip flexion mechanics at toe off. We hypothesized that an exosuit of the same basic architecture could be well applied to individuals with transfemoral amputation. In this paper, we simulate the effects of such a device for 18 patients of K2 and K3 Medicare functional classification levels. The device consists of two parallel elastic bands. Our approach considers the wrapping and geometric behavior of these elements over the residual limb in full-body patient-specific kinematic simulations of level ground walking. A nonlinear least squares problem was solved via the Levenberg-Marquardt method to find the band properties that best match (in order to offset) the intrinsic power delivery of the muscles during the swing phase. We found higher mobility patients (K3) often require a stiffer device, which leads to a greater error in the kinetic match between the biological limb and exosuit. In contrast, this method appears to be effective for K2 patients, which suggests that a different means of parameter selection or power delivery (e.g., active devices) may be necessary for higher mobility levels.

Preliminary Assessment of Two Simultaneous and Proportional Myocontrol Methods for 3-DoFs Prostheses Using Incremental Learning.

Despite progressive developments over the last decades, current upper limb prostheses still lack a suitable control able to fully restore the functionalities of the lost arm. Traditional control approaches for prostheses fail when simultaneously actuating multiple Degrees of Freedom (DoFs), thus limiting their usability in daily-life scenarios. Machine learning, on the one hand, offers a solution to this issue through a promising approach for decoding user intentions but fails when input signals change. Incremental learning, on the other hand, reduces sources of error by quickly updating the model on new data rather than training the control model from scratch. In this study, we present an initial evaluation of a position and a velocity control strategy for simultaneous and proportional control over 3-DoFs based on incremental learning. The proposed controls are tested using a virtual Hannes prosthesis on two healthy participants. The performances are evaluated over eight sessions by performing the Target Achievement Control test and administering SUS and NASA-TLX questionnaires. Overall, this preliminary study demonstrates that both control strategies are promising approaches for prosthetic control, offering the potential to improve the usability of prostheses for individuals with limb loss. Further research extended to a wider population of both healthy subjects and amputees will be essential to thoroughly assess these control paradigms.

Functional assessment of current upper limb prostheses: An integrated clinical and technological perspective.

Although recent technological developments in the field of bionic upper limb prostheses, their rejection rate remains excessively high. The reasons are diverse (e.g. lack of functionality, control complexity, and comfortability) and most of these are reported only through self-rated questionnaires. Indeed, there is no quantitative evaluation of the extent to which a novel prosthetic solution can effectively address users' needs compared to other technologies. This manuscript discusses the challenges and limitations of current upper limb prosthetic devices and evaluates their functionality through a standard functional assessment, the Assessment of Capacity for Myoelectric Control (ACMC). To include a good representation of technologies, the authors collect information from participants in the Cybathlon Powered Arm Prostheses Race 2016 and 2020. The article analyzes 7 hour and 41 min of video footage to evaluate the performance of different prosthetic devices in various tasks inspired by activities of daily living (ADL). The results show that commercially-available rigid hands perform well in dexterous grasping, while body-powered solutions are more reliable and convenient for competitive environments. The article also highlights the importance of wrist design and control modality for successful execution of ADL. Moreover, we discuss the limitations of the evaluation methodology and suggest improvements for future assessments. With regard to future development, this work highlights the need for research in intuitive control of multiple degrees of freedom, adaptive solutions, and the integration of sensory feedback.

Community-wide feasibility of the Lower Extremity Amputation Protocol amongst vascular amputees.

BACKGROUND: The Lower Extremity Amputation Protocol (LEAP) is a multidisciplinary enhanced recovery after surgery pathway for vascular amputees. The objective of this study was to examine feasibility and outcomes of community-wide implementation of LEAP. METHODS: LEAP was implemented at three safety net hospitals for patients with peripheral artery disease or diabetes requiring major lower extremity amputation. Patients who underwent LEAP (LEAP) were matched 1:1 with retrospective controls (NOLEAP) on hospital location, need for initial guillotine amputation, and final amputation type (above- vs below-knee). Primary endpoint was postoperative hospital length of stay (PO-LOS). RESULTS: A total of 126 amputees (63 LEAP and 63 NOLEAP) were included with no difference between baseline demographics and co-morbidities between the groups. After matching, both groups had the same prevalence of amputation level (76% below-knee vs 24% above-knee). LEAP patients had shorter duration of postamputation bed rest (P = .003) and were more likely to receive limb protectors (100% vs 40%; P ≤ .001), prosthetic counseling (100% vs 14%; P ≤ .001), perioperative nerve blocks (75% vs 25%; P ≤ .001), and postoperative gabapentin (79% vs 50%; P ≤ .001). Compared with NOLEAP, LEAP patients were more likely to be discharged to an acute rehabilitation facility (70% vs 44%; P = .009) and less likely to be discharged to a skilled nursing facility (14% vs 35%; P = .009). The median PO-LOS for the overall cohort was 4 days. LEAP patients had a shorter median PO-LOS (3 [interquartile range, 2-5] vs 5 [interquartile range, 4-9] days; P < .001). On multivariable logistic regression, LEAP decreased the odds of a PO-LOS of ≥4 days by 77% (odds ratio, 0.23; 95% confidence interval, 0.09-0.63). Overall, LEAP patients were significantly less likely to have phantom limb pain (5% vs 21%; P = .02) and were more likely to receive a prosthesis (81% vs 40%; P ≤ .001). In a multivariable Cox proportional hazards model, LEAP was associated with an 84% reduction in time to receipt of prosthesis (hazard ratio, 0.16; 95% confidence interval, 0.085-0.303; P < .001). CONCLUSIONS: Community wide implementation of LEAP significantly improved outcomes for vascular amputees demonstrating that utilization of core ERAS principles in vascular patients leads to decreased PO-LOS and improved pain control. LEAP also affords this socioeconomically disadvantaged population a greater opportunity to receive a prosthesis and return to the community as a functional ambulator.

Comparing Patient and Provider Priorities Around Amputation Level Outcomes Using Multiple Criteria Decision Analysis.

BACKGROUND: Patients with chronic limb threatening ischemia may require a transmetatarsal amputation (TMA) or a transtibial amputation. When making an amputation-level decision, these patients face a tradeoff-a TMA preserves more limb and may provide better mobility but has a lower probability of primary wound healing and may therefore result in additional same or higher level amputation surgeries with an associated negative impact on function. Understanding differences in how patients and providers prioritize these tradeoffs and other outcomes may enhance shared decision-making. OBJECTIVES: Compare patient priorities with provider perceptions of patient priorities using Multiple Criteria Decision Analysis (MCDA). METHODS: The MCDA Analytic Hierarchy Process was chosen due to its low cognitive burden and ease of implementation. We included 5 criteria (outcomes): ability to walk, healing after amputation surgery, rehabilitation program intensity, limb length, and ease of use of prosthetic/orthotic device. A national sample of dysvascular lower-limb amputees and providers were recruited from the Veterans Health Administration with the MCDA administered online to providers and telephonically to patients. RESULTS: Twenty-six dysvascular amputees and 38 providers participated. Fifty percent of patients had undergone a TMA; 50%, a transtibial amputation. When compared to providers, patients placed higher value on TMA (72% vs. 63%). Patient versus provider priorities were ability to walk (47% vs. 42%), healing (18% vs. 28%), ease of prosthesis use (17% vs. 13%), limb length (11% vs. 13%), and then rehabilitation intensity (7% vs. 6%). LIMITATIONS: Our sample may not generalize to other populations. CONCLUSIONS: Provider perceptions aligned with patient values on amputation level but varied around the importance of each outcome. IMPLICATIONS: These findings illuminate some differences between patients' values and provider perceptions of patient values, suggesting a role for shared decision-making. Embedding this MCDA framework into a future decision aid may facilitate these discussions.

Simultaneous assessment and training of an upper-limb amputee using incremental machine-learning-based myocontrol: a single-case experimental design.

BACKGROUND: Machine-learning-based myocontrol of prosthetic devices suffers from a high rate of abandonment due to dissatisfaction with the training procedure and with the reliability of day-to-day control. Incremental myocontrol is a promising approach as it allows on-demand updating of the system, thus enforcing continuous interaction with the user. Nevertheless, a long-term study assessing the efficacy of incremental myocontrol is still missing, partially due to the lack of an adequate tool to do so. In this work we close this gap and report about a person with upper-limb absence who learned to control a dexterous hand prosthesis using incremental myocontrol through a novel functional assessment protocol called SATMC (Simultaneous Assessment and Training of Myoelectric Control). METHODS: The participant was fitted with a custom-made prosthetic setup with a controller based on Ridge Regression with Random Fourier Features (RR-RFF), a non-linear, incremental machine learning method, used to build and progressively update the myocontrol system. During a 13-month user study, the participant performed increasingly complex daily-living tasks, requiring fine bimanual coordination and manipulation with a multi-fingered hand prosthesis, in a realistic laboratory setup. The SATMC was used both to compose the tasks and continually assess the participant's progress. Patient satisfaction was measured using Visual Analog Scales. RESULTS: Over the course of the study, the participant progressively improved his performance both objectively, e.g., the time required to complete each task became shorter, and subjectively, meaning that his satisfaction improved. The SATMC actively supported the improvement of the participant by progressively increasing the difficulty of the tasks in a structured way. In combination with the incremental RR-RFF allowing for small adjustments when required, the participant was capable of reliably using four actions of the prosthetic hand to perform all required tasks at the end of the study. CONCLUSIONS: Incremental myocontrol enabled an upper-limb amputee to reliably control a dexterous hand prosthesis while providing a subjectively satisfactory experience. The SATMC can be an effective tool to this aim.

Development and validation of the Self-Management Assessment for the Residuum and prosThesis system designed for persons with limb loss (SMART).

OBJECTIVE: To develop a system of reliable and valid knowledge assessments of self-management in persons with lower limb loss, along with the accompanying targeted educational interventions (TEIs), known as the Self-Management Assessment for the Residuum and prosThesis (SMART) system. DESIGN: This 2-phase study used mixed methodology. Phase 1 was development, face validation, and content validation of the 60-item knowledge assessment measure (SMART 60) and the TEI. Phase 2 assessed internal consistency reliability using Kuder-Richardson Formula 20 and the creation of the SMART system, consisting of modules developed from the SMART 60. Validity of the measures using known groups' comparison was analyzed by comparing clinicians (prosthetists and physical therapists) with persons with lower limb loss. Participants were recruited from the Amputee Coalition National Conference in 2018 and 2019. RESULTS: A total of 140 participants completed this study. Four modules from the SMART 60 were created and designed to integrate as a system. Face validity survey average scores found that 9/10 participants either agreed or strongly agreed that the SMART system has high readability, perceived usefulness, and value for both new and experienced prosthetic users. Measure length ranged from 10 to 45 items with a reliability ranging from Kuder-Richardson Formula 20 = 0.70-0.82. The SMART system demonstrated known-groups validity ( p < 0.05). CONCLUSION: The SMART system is an integrated series of self-management knowledge assessments with reasonable to good internal consistency reliability and known-groups validity. The TEIs provide directed solutions to identified knowledge gaps on the assessments.

Health utility in community-dwelling adults with dysvascular lower limb loss.

PURPOSE: Adults with dysvascular lower extremity amputation (LEA) experience a large number of secondary health conditions yet there is a gap in the literature on health utility scores for this population. A health utility score relates to a person's state of well-being, and is a single metric anchored at 0 (death) and 1 (perfect health). This study aimed to provide a descriptive account of health utility scores in community-dwelling adults with dysvascular LEA. METHODS: Participants were adults with dysvascular LEA who were 3 months post-amputation. Data collected included socio-demographic characteristics, the Special Interest Group in Amputee Medicine (SIGAM) grades, the dysvascular conditions scale (DCS), which is a scale developed for this study, and the Short Form-36 (SF-36). SF-6D health utility scores were derived from the SF-36 using a software algorithm. Participants were grouped into low-impact and high-impact groups based on self-reported severity of symptoms using the DCS. Health utility scores were compared between the low-impact and high-impact groups using independent t-tests. RESULTS: A total of 231 participants were enrolled in the study. The mean SF-6D health utility score was 0.689 (0.127). A significant association was found between health utility score and SIGAM grade (p < 0.001, η2 = .09). Health utility was positively associated with age (r = 0.137, p = 0.037) and months post-amputation (r = 0.141, p = 0.032), and negatively associated with DCS severity (r = -0.526, p < 0.001). Health utility scores were lower for participants in the DCS high-impact groups for conditions such as diabetes mellitus, phantom limb pain, musculoskeletal pain, back pain, psychological distress, depression, vision problems, and other pain. CONCLUSION: Cost-utility analyses rely on health utility estimates and our findings provide data for future economic evaluations that may assist policy makers in evidence informed allocation of healthcare resources for this population.

Assessment of efficiency of mirror therapy in preventing phantom limb pain in patients undergoing below-knee amputation surgery-a randomized clinical trial.

PURPOSE AND OBJECTIVES: Phantom limb pain (PLP) is a major cause of physical limitation and disability accounting for about 85% of amputated patients. Mirror therapy is used as a therapeutic modality for patients with phantom limb pain. Primary objective was to study the incidence of PLP at 6 months following below-knee amputation between the mirror therapy group and control group. METHODS: Patients posted for below-knee amputation surgery were randomized into two groups. Patients allocated to group M received mirror therapy in post-operative period. Two sessions of therapy were given per day for 7 days and each session lasted for 20 min. Patients who developed pain from the missing portion of the amputated limb were considered to have PLP. All patients were followed up for six months and the time of occurrence of PLP and intensity of the pain were recorded among other demographic factors. RESULTS: A total of 120 patients completed the study after recruitment. The demographic parameters were comparable between the two groups. Overall incidence of phantom limb pain was significantly higher in the control group (Group C) when compared to the mirror therapy (Group M) group [Group M = 7 (11.7%) vs Group C = 17 (28.3%); p = 0.022]. Intensity of PLP measured on the Numerical Rating Scale (NRS) was significantly lower at 3 months in Group M compared to Group C among patients who developed PLP [NRS - median (Inter quartile range): Group M 5 (4,5) vs Group C 6 (5,6); p 0.001]. CONCLUSION: Mirror therapy reduced the incidence of phantom limb pain when administered pre-emptively in patients undergoing amputation surgeries. The severity of the pain was also found to be lower at 3 months in patients who received pre-emptive mirror therapy. TRIAL REGISTRATION: This prospective study was registered in the clinical trial registry of India. TRIAL REGISTRATION NUMBER: CTRI/2020/07/026488.

What is the cost, impact, and willingness to pay for an Amputee Peer Support Program?

BACKGROUND: The provision of peer support from those who have already made positive adjustments to amputation is recommended for people incurring a major limb amputation; however, few receive this service. OBJECTIVE: From a program perspective, determine the cost, impact, and willingness to pay for an Amputee Peer Support Program. STUDY DESIGN: Cost analysis. METHODS: Cost of the Amputee Peer Support Program included a cost analysis of program data over a 5-year time horizon (2013-2018) reported in Australian Dollars 2018/2019. Impact and willingness to pay for an Amputee Peer Support Program was determined through surveys of the 3 participant groups: referring health professionals, program volunteers, and program participants. RESULTS: Over 5 years, there were 793 program participants, serviced by 256 program volunteers, for a cost of $631,497. The cost per program participant was $796. Thirty-eight health professionals, 86 program volunteers, and 12 program participants reported on impact and willingness to pay. The Program was reported to have a positive impact on all participant groups. The themes of access to resources and information and the provision of social and emotional well-being were identified across all 3 groups as being important. All 3 groups reported a higher willingness to pay for the health service (range $113-$450), National Disability Insurance Scheme ($156-$432), and private health insurance ($153-$347), and a lower willingness to pay for the program participant ($23-$49). CONCLUSION: Amputee peer support had a positive impact on those receiving and providing the service. Amputee peer support is likely to be a powerful yet inexpensive addition to routine care.

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.

Conformity assessment with structural strength requirements of mechanical polycentric prosthetic knee used for amputee rehabilitation.

Prosthetic restoration is an important component of amputee rehabilitation which may be subjected to a static load of nearly five times of amputees' body weight and is continuously administered to cyclic or fatigue loads during its function. This study presents a structural strength analysis of polycentric mechanical prosthetic knee commonly used in National Institutes in India by finite element simulation and its experimental validation. Static and fatigue analyses have been performed to ensure its structural integrity as per the ISO 10328:2006 standard. Accurate dimensioning of knee components have been obtained using coordinate measuring machine and the 3 D CAD model has been generated by CATIA V5 from the 2 D geometry. The model is imported to the ANSYS 20.1 workbench to study stress distribution in the knee for ensuring its safety performance. The selection of reference planes, application of calculated loads, and position of load line have been done as per the ISO test procedure. Static and cyclic loadings of 4130 N and 1230 N are applied at the top and the bottom plate is given with translational constraints to limit its movement in any direction. Results indicate that the prosthetic knee model is moderately strong enough to outstrip the static strength test. However, the calculated strain and predicted fatigue life during the cyclic test suggest that this knee unit has poor fatigue strength. Validation results with an average error percentage of 3.44 and 10 show higher reliability based on previous study results and experimental tests, respectively.

Disparities in functional recovery after dysvascular lower limb amputation are associated with employment status and self-efficacy.

PURPOSE: Employment status is considered a determinant of health, yet returning to work is frequently a challenge after lower limb amputation. No studies have documented if working after lower limb amputation is associated with functional recovery. The study's purpose was to examine the influence of full-time employment on functioning after lower limb amputation. METHODS: Multisite, cross-sectional study of 49 people with dysvascular lower limb amputation. Outcomes of interest included performance-based measures, the Component Timed-Up-and-Go test, the 2-min walk test, and self-reported measures of prosthetic mobility and activity participation. RESULTS: Average participant age was 62.1 ± 9.7 years, 39% were female and 45% were persons of color. Results indicated that 80% of participants were not employed full-time. Accounting for age, people lacking full-time employment exhibited significantly poorer outcomes of mobility and activity participation. Per regression analyses, primary contributors to better prosthetic mobility were working full-time (R2 ranging from 0.06 to 0.24) and greater self-efficacy (R2 ranging from 0.32 to 0.75). CONCLUSIONS: This study offers novel evidence of associations between employment and performance-based mobility outcomes after dysvascular lower limb amputation. Further research is required to determine cause-effect directionalities. These results provide the foundation for future patient-centered research into how work affects outcomes after lower limb amputation. IMPLICATIONS FOR REHABILITATIONLower limb amputation can pose barriers to employment and activity participation, potentially affecting the quality of life.This study found that the majority of people living with lower limb amputation due to dysvascular causes were not employed full-time and were exhibiting poorer prosthetic outcomes.Healthcare practitioners should consider the modifiable variable of employment when evaluating factors that may affect prosthetic mobility.The modifiable variable of self-efficacy should be assessed by healthcare professionals when evaluating factors that may affect prosthetic mobility.