Prosthetic fitting, use, and satisfaction following lower-limb amputation: a prospective study

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.

The prevalence of depression in people following limb amputation: A systematic review and meta-analysis

OBJECTIVE

To estimate the prevalence of depression in people with limb amputation. Additionally, factors affecting the prevalence or pattern of depression following limb amputation were explored.

METHODS

Systematic literature search to identify all relevant studies assessing prevalence of depression following limb amputations was conducted through following databases: PubMed/ MEDLINE, Scopus, Embase, and Web of Science. Search period was since inception of database till December 2021. Meta-analyses using random-effects model were conducted to estimate pooled prevalence of depression.

RESULTS

A total of 61 studies comprising 9852 limb amputees were included. Pooled prevalence of depression following limb amputations was 33.85% (95% CI: 27.15% to 40.54%), with significant heterogeneity (I2 = 98.57%; p < 0.001). Sub-group meta-analysis showed that pooled prevalence of depression was significantly higher in studies conducted from middle-income (45.31%, 95% CI: 28.92% to 61.70%) as compared high income countries (28.31%, 95% CI: 23.97% to 32.64%). Greater activity restriction, amputation-related body image disturbances, social discomfort, perceived vulnerability regarding disability, and avoidant coping style were commonly reported factors associated with greater depression symptomatology. Whereas, good perceived social support, and use of more active coping strategies were commonly reported protective factors.

CONCLUSION

About one-third of all limb amputees suffered from clinically significant depression. This emphasizes need to sensitize health care professionals involved in providing care to people following limb amputation regarding the importance of periodically screening this vulnerable group of patients for depression and liaising with psychiatrists. Further, addressing risk factors identified in this review could help in reducing the rates of depression post-amputation.

Development and alpha testing of a patient shared decision aid for prosthesis design for new lower limb prosthesis users

BACKGROUND

After lower limb amputation, several prosthesis design options exist. However, prosthesis design decisions do not always reflect a prosthesis user's needs, values, and preferences.

OBJECTIVE

To develop a patient decision aid (PDA) prototype for prosthetists and new prosthesis users facing prosthesis design decisions after lower limb amputation, and to assess its usability, accuracy, and comprehensibility.

STUDY DESIGN

Exploratory mixed methods.

METHODS

PDA development was informed by a qualitative needs assessment and guided by the International Patient Decision Aid Standards. The PDA was evaluated by steering groups of experienced prosthesis users and prosthetic professionals (prosthetists and researchers) to test usability, accuracy, and comprehensibility through focus groups, individual interviews, and rating on a Likert scale ranging from 1 to 10.

RESULTS

The resulting PDA included 6 sections: (1) Amputation and Early Recovery, (2) Communication, (3) Values, (4) Prosthesis Design, (5) Preferences, and (6) Prosthetic Journey. Usability, accuracy, and comprehensibility were rated as 9.2, 9.6, and 9.6, respectively, by prosthetic professionals, and 9.4, 9.6, and 9.6, respectively, by prosthesis users.

DISCUSSION

The PDA incorporated guidance by relevant stakeholders and was rated favorably, emphasizing a need for shared decision-making support in prosthesis design. One challenge was determining the amount of information in the PDA, highlighting the diversity in end users' informational needs. Future iterations of the PDA should undergo beta testing in clinical settings.

CONCLUSIONS

A standardized, iterative method was used to develop a PDA for new lower limb prosthesis users and prosthetists when considering prosthesis design decisions. The PDA was considered useable, accurate, and comprehensible.

Gender differences in prosthesis-related outcomes among veterans: Results of a national survey of U.S. veterans

BACKGROUND

Women with lower extremity amputations (LEAs) tend to have poorer prosthesis-related outcomes than men, although the literature is sparse. To our knowledge, there are no prior studies examining prosthesis-related outcomes of women veterans with LEAs.

OBJECTIVE

To examine gender differences (overall and by type of amputation) among veterans who underwent LEAs between 2005 and 2018, received care at the Veterans Health Administration (VHA) prior to undergoing amputation, and were prescribed a prosthesis. It was hypothesized that compared to men, women would report lower satisfaction with prosthetic services, poorer prosthesis fit, lower prosthesis satisfaction, less prosthesis use, and worse self-reported mobility. Furthermore, it was hypothesized that gender differences in outcomes would be more pronounced among individuals with transfemoral than among those with transtibial amputations.

DESIGN

Cross-sectional survey. Linear regressions were used to assess overall gender differences in outcomes and gender differences based on type of amputation in a national sample of veterans.

SETTING

VHA medical centers.

PARTICIPANTS

The sample consisted of 449 veterans who self-identified their gender (women = 165, men = 284) with transtibial (n = 236), transfemoral (n = 135), and bilateral LEAs (n = 68) including all amputation etiologies.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The Orthotics and Prosthetics User's Survey, Trinity Amputation and Prosthesis Experiences Scale, and Prosthetic Limb Users Survey of Mobility-Short Form were used to assess satisfaction with prosthetic services, prosthesis fit, prosthesis satisfaction, prosthesis use, and self-reported mobility.

RESULTS

Women had poorer self-reported mobility than men (d = -0.26, 95% confidence interval -0.49 to -0.02, p < .05); this difference was small. There were no statistically significant gender differences in satisfaction with prosthetic services, prosthesis fit, prosthesis satisfaction, daily hours of prosthesis use, or by amputation type.

CONCLUSIONS

Contrary to the hypothesis, prosthesis-related outcomes were similar between men and women with LEAs. Minimal differences may in part be due to receiving care from the VHA's integrated Amputation System of Care.

The effect of depression on prosthesis prescription in men and women who have undergone a lower limb amputation

PURPOSE

To determine gender disparities and potential factors that modify prosthesis prescription practices in veteran patients who have undergone their first major unilateral amputation due to diabetes or peripheral arterial disease.

MATERIALS AND METHODS

A retrospective cohort study using the VA Corporate Data Warehouse to compare prosthesis prescription rates and time to prescription between men and women veterans. The primary exposure was gender. The primary outcome was a qualifying prosthesis prescription within 12 months of the incident amputation. The secondary outcome was time to prosthesis prescription. Multiple logistic and linear regression was used to control for potential confounders and identify potential effect modification.

RESULTS

2,862 individuals met study criteria, with 1690 (60%) prescribed a qualifying prosthesis. Men were more likely to receive a prosthesis prescription than women (59% versus 45%, respectively; p = 0.03). This difference was observed primarily among those with a diagnosis of major depressive disorder. In this subgroup, the odds of men receiving a prosthesis over women was over 3 times (adjusted odds ratio = 3.3; 95% Confidence Interval, 1.5, 7.4). Men had a mean shorter time to prescription compared to women (112 ± 72 versus 136 ± 79 days, respectively, p = 0.08).

Depression in women negatively impacts their prosthesis prescription rates and time to prescription compared to men. This disparity may have significant impacts on future function and quality of life.Implications for RehabilitationThis study found that men more commonly received a prosthesis prescription and received it earlier than women.This disparity was most extreme among women who had been diagnosed with major depressive disorder.Providers should identify at risk patients early and consider targeted interventions to address depression during the preoperative and immediate postoperative phases.Future research should continue to work to identify gender-specific needs that exacerbate disparity.

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.

Knee disarticulation vs. transfemoral amputation after failed transtibial amputation: Surgical outcome and prosthetic fitting in patients with peripheral vascular disease

OBJECTIVE

Our aim was to compare transfemoral amputation (TFA) to knee disarticulation (KD) as a reamputation level after failed transtibial amputation (TTA) in patients with peripheral vascular disease and/or diabetes.

METHODS

We studied 152 patients undergoing reamputation, 86 TFA and 66 KD, after a failed TTA. The primary outcome was reamputation and reoperation, and secondary outcomes were prosthetic fitting and mortality. Logistic regression analyses were performed to identify factors associated with the outcome.

RESULTS

The reamputation rate was 36% after KD and 15% after TFA ( p = 0.004). The multivariable analysis showed that TFA was associated with a significantly reduced risk of reamputation, odds ratio (OR) = 0.31 (95% confidence interval [95% CI], 0.1-0.7). The overall reoperation rate was 38% after KD and 22% after TFA ( p = 0.03). This reduction of risk for TFA was not significant in the multivariable analysis, OR = 0.49 (95% CI, 0.2-1.0). Prosthetic limb fitting was possible in 30% after KD and 19% after TFA ( p = 0.1). Previous amputation in the contralateral leg was the only factor associated with reduced ability for prosthetic fitting in the multivariable analysis, OR = 0.15 (95% CI, 0.03-0.7). Mortality at 30 d was 17% and 53% at 1 year. No independent factors affected 30-d mortality in the multivariable analysis.

CONCLUSIONS

In this study, we found a significantly lower risk of reamputation after TFA compared with KD after a failed TTA. We consider TFA to be the reamputation level of choice, especially when there is a need of reducing risk of further reamputations.

Depression and Anxiety Symptoms Among Lebanese Lower Limb Traumatic Amputees: Association with Education, Employment, Adjustment to Amputation and Prosthesis Satisfaction

ObjectiveTo examine and compare the association between the presence of depression and anxiety symptoms and different sociodemographic and clinical factors including the adjustment to amputation and prosthesis satisfaction among Lebanese individuals with lower limb amputation (LLA). Method: This cross-sectional study was conducted between December 2022 and May 2023 among 72 participants with LLA. Participants completed a questionnaire that included sociodemographic and clinical variables, the revised Trinity Amputation and Prosthesis Experience Scale (TAPES-R), and the Hopkins Symptom Checklist (HSCL-25). Result: Using the HSCL depression and anxiety cut-off, 25% of participants were categorized as having depression symptoms, with unemployment being significantly associated (p-value < .05) with depression. Similarly, 25% were classified as having anxiety symptoms, with both lower education and unemployment (p-value < .05) significantly linked to anxiety. TAPES-R subscales scores exhibited significant differences between non-depressed and depressed, as well as non-anxious and anxious participants (p-value < .05). Correlation analysis demonstrated significant relationship between HSCL scales and TAPES-R subscales; lower scores in adjustment to amputation and prosthesis satisfaction were moderately associated with increased rates of depression (r ranging between -0.331 and -0.500, p-values < .005) and increased rates of anxiety symptoms (r ranging between -0.362 and -0.441, p-values < .002). In addition, higher scores in activity limitation were moderately correlated to increased rates of depression and anxiety (r = 0.438 for anxiety and 0.490 for depression; p < .001). Conclusion: Mental health symptoms are associated with educational level, employment status, and adjustment to amputation and prosthesis satisfaction in Lebanese individuals with LLA. These findings should be considered to achieve optimal prosthetic rehabilitation.

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.

Predicting Prosthetic Mobility at Discharge From Rehabilitation Following Major Amputation in Vascular Surgery

OBJECTIVE

This study aimed to construct a decision aid to estimate the likelihood of independence with a prosthesis following rehabilitation for limb loss secondary to advanced ischaemia (acute or chronic limb threatening ischaemia) or diabetic foot disease (DFD). A secondary aim was to determine whether prosthetic independence is a surrogate marker of long term survival.

METHODS

A retrospective cohort study of a prospectively maintained database of unilateral amputations due to ischaemia or DFD entering rehabilitation between 2007 and 2020 was performed. Predictors of independent prosthetic mobility (IPM) were used in construction of the IPM prediction model, which underwent bootstrap internal and criterion validation through correlation with predictors of other measures of function: Timed Up and Go (TUG) and two minute walk test. Kaplan-Meier and Cox regression analyses were performed to address the secondary aim.

RESULTS

Of the 771 patients included, only 49.9% of amputees achieved IPM. Independent negative predictors of IPM were age > 75 years, female sex, higher amputation level, active malignancy, cerebrovascular disease, end stage renal disease, and cognitive impairment. The model yielded high discrimination (C statistic 0.778), and internal validation was demonstrated with bootstrapping (C statistic 0.778), confirming no over optimism. There was a strong correlation between IPM, TUG, and two minute distance and their predictors, confirming strong criterion validity. The IPM group had a median survival of 93.7 (80.7, 105) months, whereas the non-IPM group fared worse with a median survival of 56.6 (48.5, 66.7) months (p < .001).

CONCLUSION

An internally validated decision aid for estimating the likelihood of independence with a prosthesis after major amputation was constructed. A strong association between female sex and poorer prosthetic mobility was observed. Prosthetic function was shown to be a surrogate marker of long term survival. Future research will involve external validation studies to confirm the generalisability of the decision aid in clinical practice.

Development of a prosthetic fit and alignment assessment (ProFit) in persons with post-traumatic transtibial amputation

BACKGROUND

There are no standards for reliably measuring the quality of prosthetic fit and alignment which is important for evaluation and improvement of clinical care for patients with transtibial amputation.

OBJECTIVES

The purpose of this study was to develop an instrument to quantitatively assess prosthetic fit and alignment in patients with transtibial amputation.

STUDY DESIGN

Prospective cohort study.

METHODS

The fit and alignment assessment (ProFit) included 39 items for assessments of skin quality, stance and gait, and radiographic characteristics that could be feasibly captured in clinic using photographs, video, and radiographs. Data were collected on adults aged 18-60 years treated with transtibial amputation and followed up for 18 months at 1 of 27 US hospitals. One hundred thirteen assessments were conducted by 6 prosthetists using an online platform. Items demonstrating reliability and face validity were included in the ProFit score for subsequent validation testing. Validation measures included 18-month patient-reported function (Short Musculoskeletal Function Assessment ), tests of physical performance, patient-reported pain (Brief Pain Inventory ), satisfaction with prosthesis (Orthotics Prosthetics Users Survey), prosthesis use, and walking activity.

RESULTS

The ProFit score included 10 of 39 items that demonstrated high inter-rater reliability and face validity. A higher ProFit score correlated with worse function on all domains of the Short Musculoskeletal Function Assessment except arm and hand and with worse performance on the 4-Square Step Test, Shuttle Run, and Illinois Agility Test. ProFit scores did not correlate with the Brief Pain Inventory, Orthotics Prosthetics Users Survey, prosthesis use, or walking activity.

CONCLUSIONS

The ProFit score can be used by researchers and clinicians to measure the quality of socket fit and prosthetic alignment. Future prospective validation is necessary to verify the promising results observed in ProFit development and establish clinical utility.

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.

3D Motion Analysis for the Assessment of Dynamic Coupling in Transtibial Prosthetics: A Proof of Concept

Assessment of coupling between transtibial sockets and users is historically based on clinicians' observations and experience, but can be inaccurate and unreliable. Therefore, we present a proof of concept, for five out of six possible degrees of freedom coupling metric system for a socket, using motion analysis calibrated on a 3D printed limb substitute. The method is compatible with any socket suspension method and does not require prior modifications to the socket. Calibration trials were used to locate the axis of rotation of the knee joint referenced against a marker cluster on the thigh; this allowed for the identification of the limb during test trials despite the entire residuum being obscured from view by the socket. The error in the technique was found to be within 0.7 mm in displacement and 0.7 degrees in rotation, based on the control data. Dynamic testing showed the Inter Quartile Range (IQR) of inter time step variance was <0.5 mm/deg for all metrics. The method can form a basis for objective socket evaluation, improve clinical practice and the quality of life for amputees.

Toward higher-performance bionic limbs for wider clinical use

Most prosthetic limbs can autonomously move with dexterity, yet they are not perceived by the user as belonging to their own body. Robotic limbs can convey information about the environment with higher precision than biological limbs, but their actual performance is substantially limited by current technologies for the interfacing of the robotic devices with the body and for transferring motor and sensory information bidirectionally between the prosthesis and the user. In this Perspective, we argue that direct skeletal attachment of bionic devices via osseointegration, the amplification of neural signals by targeted muscle innervation, improved prosthesis control via implanted muscle sensors and advanced algorithms, and the provision of sensory feedback by means of electrodes implanted in peripheral nerves, should all be leveraged towards the creation of a new generation of high-performance bionic limbs. These technologies have been clinically tested in humans, and alongside mechanical redesigns and adequate rehabilitation training should facilitate the wider clinical use of bionic limbs.

Body image and perception among adults with and without phantom limb pain

BACKGROUND

Following lower-limb amputation, phantom limb pain (i.e., pain perceived as coming from the amputated portion of the limb) is common. Phantom limb pain may be associated with impaired body image and perception, which may be targets for rehabilitative intervention.

OBJECTIVE

To compare measures of body image and perception between adults with and without phantom limb pain post amputation and evaluate associations between measures of body image and perception and phantom limb pain.

DESIGN

Survey.

SETTING

Online, remote assessment.

PARTICIPANTS

Seventy-two adults ≥1 year post unilateral lower-limb loss (n = 42 with phantom limb pain, n = 30 without phantom limb pain or pain in the remaining portion of the limb).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Self-reported outcome measures assessing body image (i.e., Amputee Body Image Scale-Revised), perceptual disturbances associated with the phantom limb (i.e., a modified Bath Complex Regional Pain Syndrome Body Perception Disturbance Scale), and prosthesis satisfaction (i.e., Trinity Amputation and Prosthesis Experience Scale) were administered; participants with phantom limb pain reported pain interference via the Brief Pain Inventory-Short Form. Between-group comparisons of self-reported outcome measure scores were conducted using Mann Whitney U or chi-square tests, as appropriate (a = .05).

RESULTS

Compared to peers without phantom limb pain, adults with phantom limb pain reported more negative body image; increased phantom limb ownership, attention, and awareness; and reduced prosthesis satisfaction and embodiment (U = 175.50-364.00, p < .001 to .034). Disturbances in phantom limb perception (i.e., size, weight, pressure, temperature) were similar between groups (p = .086 to >.999). More negative body image was associated with increased phantom limb pain interference (τb  = .25, p = .026).

CONCLUSIONS

Adults with phantom limb pain demonstrate more negative body image and hypervigilance of the phantom limb as compared to peers with nonpainful phantom sensations. Mind-body treatments that target impaired body image and perception may be critical interventions for adults with phantom limb pain.

Gait Alteration in Individual with Limb Loss: The Role of Inertial Sensors

Amputation has a big impact on the functioning of patients, with negative effects on locomotion and dexterity. In this context, inertial measurement units represent a useful tool in clinical practice for motion analysis, and in the development of personalized aids to improve a patient's function. To date, there is still a gap of knowledge in the scientific literature on the application of inertial sensors in amputee patients. Thus, the aim of this narrative review was to collect the current knowledge on this topic and stimulate the publication of further research. Pubmed, Embase, Scopus, and Cochrane Library publications were screened until November 2022 to identify eligible studies. Out of 444 results, we selected 26 articles focused on movement analysis, risk of falls, energy expenditure, and the development of sensor-integrated prostheses. The results showed that the use of inertial sensors has the potential to improve the quality of life of patients with prostheses, increasing patient safety through the detection of gait alteration; enhancing the socio-occupational reintegration through the development of highly technologic and personalized prosthesis; and by monitoring the patients during daily life to plan a tailored rehabilitation program.

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.

Protocol for a randomized controlled trial to assess the effect of Self-Management for Amputee Rehabilitation using Technology (SMART): An online self-management program for individuals with lower limb loss

BACKGROUND

Lower limb loss (LLL) is a distressing experience with psychological, physical, and social challenges. Education is needed to enhance the coping skills and confidence of patients to improve LLL outcomes. However, access to rehabilitation services and education is limited outside of urban centers. To address this service gap, we co-created an eHealth platform, called Self-Management for Amputee Rehabilitation using Technology (SMART).

OBJECTIVES

First, we will test the effect of SMART and usual care compared with usual care only on walking capacity and confidence among individuals with LLL. Second, we will describe key implementation factors for program delivery and adoption at the person- and provider-level.

METHODS

This is a Type 1 Effectiveness-Implementation Hybrid Design, mixed-methods, multi-site (British Columbia and Ontario, Canada), parallel, assessor-blinded randomized controlled trial. Participants will include adults with unilateral LLL, during early prosthetic fitting (<2 years after casting for initial prosthesis). Participants in both groups will receive usual care. The experimental group will receive SMART with weekly support sessions from a trained peer mentor for goal setting and action planning for six weeks. Participants will be encouraged to continue using SMART for an additional four weeks. The control group will receive usual care, and weekly social contacts for six weeks. The primary outcome measure is walking capacity operationalized as the performance based Timed Up and Go test. The secondary outcome is walking confidence using the Ambulatory Self-Confidence Questionnaire. Outcome measures will be assessed at baseline, immediately post-intervention, and four weeks follow-up. We will describe key implementation factors (such as, participant experience, intervention adoption, fidelity) throughout the study using questionnaires, semi-structured interviews, and direct observation.

RESULTS

No participants have been enrolled.

CONCLUSIONS

SMART has the potential to provide knowledge and skill development to augment rehabilitation outcomes for adults with LLL.

TRIAL REGISTRATION

NCT04953364 in Clinical Trial Registry (https://clinicaltrials.gov/).

The Psychosocial Impact of Lower Limb Amputation on Patients and Caregivers

Introduction The impact of amputation on patients' social and psychological well-being has been demonstrated. However, the experiences and requirements of amputees during the adjustment phase vary between amputees. Methods This study aimed to assess how amputation affects psychosocial life and the quality of life (QOL) in the amputees, the psychosocial processes involved in adjusting to amputation and a prosthesis, and the burden of amputees on caregivers in Saudi Arabia. A cross-sectional study was placed from November 2021 to February 2022, and it included all amputees and caregivers available at the time of the study. Result A total of 239 amputees and 219 caregivers were included in the study. The average level of the physical component score (PCS) was 63.5% ± 14.6% and 57.3% ± 12.9% for the mental component score (MCS). There is a significant positive correlation between psychological adjustment total and satisfaction with prosthesis with PCS and MCS dimension of QOL. Considering the QOL, PCS mean score was significantly higher among prosthetics users than among non-users (68.2 ± 15.5 vs. 59.9 ± 12.8, respectively; P=.001). Also, the MCS score was significantly higher among prosthetics users than among non-users (59.5 ± 12.4 vs. 55.5 ± 13.0, respectively; P=.001). A total of 15.1% of caregivers experienced a high burden, while 23.3% had a mild to moderate burden, but 61.6% had no or little burden.  Conclusion Our finding shows there are correlations between psychological adjustment total and satisfaction with prosthesis with PCS and MCS dimension of QOL. The findings emphasize the importance of psychological and social support to be considered in caregivers' health assessments. Also, the physical health of the caregivers should be fundamental in their lives as it minifies the caregiver burden. Further studies should be considered with a larger sample of amputees and longitudinal studies to evaluate the adaptation changes over time, caregiving burden, and family functioning.

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.

How to build a limb salvage program

Patients with chronic limb-threatening ischemia (CLTI) are medically complex and continue to experience high rates of amputation, despite improved diagnosis and treatment. Limb salvage programs and multidisciplinary teams provide comprehensive patient care and have been associated with reduced amputation rates. Recent societal guidelines suggest the adoption of limb salvage programs to improve care of patients with CLTI. In this article, we describe the critical components of a limb salvage program and outline the following steps to aid in their construction: community and institution assessment, formation of a multidisciplinary team, provision of patient care, and monitoring outcomes and processes refinement.

[Factors related to success in the prosthetic fitting of lower limb amputees from vascular etiology]

OBJECTIVE

Restoring the ambulation ability with prostheses in lower limb amputeesis essential to improve their functional independence. The aim of this study was to determine the factors involved in achieving prosthesis fitting in vascular amputees.

MATERIAL AND METHOD

Observational longitudinal study of patients with major lower limb amputation of vascular etiology performed from April 1st 2017 to April 1st 2020. The following variables were compared between the group of patients who were prosthetized and those who were not: age, gender, body-mass index, comorbidity (Charlson index), independence in the activities of daily living (Barthel index) and ambulation ability (FAC test) before and a year after the amputation. The prosthetic use after a year was measured with the Houghton scale.

RESULTS

A total of 80 patients were amputated with a mean age of 70.5 years old, 78.8% were male. The amputation level was supracondilealin 42 patients and infracondilealin 38 patients. The number of prosthetized patients was 35. The variables related to the possibility of prosthesis fitting were: younger age (P=0.020), less comorbidity (P=0.000), infracondileal amputation (P=0.024) and greater functional independence and ambulation ability prior to amputation (P=0.000). After a year 22 patients had died, only one of those who had been prosthetized.

CONCLUSIONS

Although there are no clear recommendations to determine which amputees should be prosthetic fitting, in our patients the presence of fewer comorbidities and a good previous functional situation, younger age and infracondileal amputation, are related to greater success in achieving this objective.

A prospective assessment of an adjustable, immediate fit, subischial transfemoral prosthesis

Objective

To assess the feasibility of an adjustable, subischial transfemoral prosthesis by comparing self-reported outcome measures regarding socket comfort, fit and utility relative to a persons’ conventionally made socket. Assessing limb compressibility was another aim of this study.

Design

A single-group pre-post intervention design.

Setting

Physical medicine and rehabilitation biomechanics laboratory.

Participants

All 18 enrolled participants (N = 18) completed the feasibility trial. There were 16 men and 2 women with an average age of 59.4 (±7) years. Most of the participants (61.1%) had worn a socket for 1 to 10 years before the trial, 22.2% of the participants had worn one for less than a year, and 16.7% of the participants had worn a prosthesis for more than 10 years.

Intervention

Participants were fit with the study prosthesis and used it for a 2-week home trial.

Main Outcome Measures

A Prosthetic Comfort and Utility Questionnaire was completed on the participant's conventional prosthetic device and the subischial socket system after the trial.

Results

The adjustable subischial prostheses were rated superior overall to the participant's conventional sockets (40.9 ± 7.2 vs 32.8 ± 10.8; P=.004). Six of the 10 parameters measured (adjustability, overall fit, prosthesis weight, sitting comfort, standing comfort, and standing stability) were rated higher for the adjustable prostheses compared to the conventional sockets. Compression of the soft tissues of the thigh ranged from 5.6 ± 4.2 cm at the distal end to 7.3 ± 3.6 cm at the proximal site. There were no falls, skin breakdown, or limb ischemia. At the 2-month telephone follow-up, 61% of subjects had transitioned to using the adjustable subischial socket most of the time.

Conclusions

The adjustable, immediate fit, subischial prosthesis provided safe, comfortable, and functional ambulation for persons with transfemoral limb loss in this short-term feasibility study. This study supports the consideration of a new paradigm in transfemoral prosthetics—adjustable subischial sockets. These devices should be tested in a larger multi-center study.

Air microfluidics-enabled soft robotic transtibial prosthesis socket liner toward dynamic management of residual limb contact pressure and volume fluctuation

Residual limb volume fluctuation and the resulting contact pressures are some of the key factors leading to skin ulcerations, suboptimal prosthetic functioning, pain, and diminishing quality of life of transtibial amputees. Self-management of socket fit is complicated by peripheral neuropathy, reducing the perception of pressure and pain in the residual limb. We introduce a novel proof-of-concept for a transtibial prosthetic socket liner with the potential to dynamically adjust the fit between the limb and socket. The core of the technology is a small air microfluidic chip (10 cm³ and 10 g) with 10 on-chip valves that enable sequential pressurizing of 10 actuators in custom sizes to match the pressures required by the residual limb's unique anatomy. The microfluidic chip largely reduced the number of electromechanical solenoid valves needed for sequential control of 10 actuators (2 instead of 10 valves), resulting in the reduction of the required power, size, mass, and cost of the control box toward an affordable and wearable prosthetic socket. Proof-of-concept testing demonstrated that the applied pressures can be varied in the desired sequence and to redistribute pressure. Future work will focus on integrating the system with biofidelic prosthetic sockets and residual limb models to investigate the ability to redistribute pressure away from pressure-sensitive regions (e.g., fibular head) to pressure tolerant areas. Overall, the dynamic prosthesis socket liner is very encouraging for creating a dynamic socket fit system that can be seamlessly integrated with existing socket fabrication methods for managing residual limb volume fluctuations and contact pressure.

Scoping review to evaluate existing measurement parameters and clinical outcomes of transtibial prosthetic alignment and socket fit

INTRODUCTION

Fit and alignment are observable objectives of the prosthesis rendering process for individuals with lower limb amputation. Nevertheless, there is a dearth of validated measures to directly assess the quality of this clinical procedure.

OBJECTIVES

The objectives of this scoping review are to evaluate existing measurement parameters and clinical outcomes used in investigations of transtibial socket fit or prosthetic alignment and to identify gaps in the literature regarding tools for evaluation of prosthetic fitting.

STUDY DESIGN

Scoping literature review.

METHODS

A comprehensive search was conducted in the following databases: MEDLINE (through PubMed), Embase (through Elsevier), Scopus (through Elsevier), and Engineering Village (through Elsevier), resulting in 6107 studies to be screened.

RESULTS

Sixty-three studies were included in the review. When measuring fit, studies most frequently reported on patient-reported comfort (n = 22) and socket size compared with the residual limb volume (n = 9). Alignment was most frequently measured by the prosthetists' judgment and/or use of an alignment jig (n = 34). The measurement parameters used to determine alignment or fit varied greatly among the included studies.

CONCLUSION

This review demonstrated that most measures of socket fit rely on a patient's self-report and may vary with biopsychosocial factors unrelated to the socket fitting process. Meanwhile, alignment is determined mostly by the prosthetist's judgment, paired with objective measurements, such as alignment jigs and gait analysis. Efforts to standardize and validate measures of these parameters of prosthetic fitting are vital to improving clinical practice and reporting outcomes.

Measuring discomfort-An objective method for quantifying peak pressure discomfort and improved fit in adults with transtibial amputation

BACKGROUND

Prosthetic socket coupling with the residual limb should be comfortable without causing skin breakdown or excessive pressure. However, users report socket discomfort, and there is a scarcity of objective measurements available to assess this feeling of discomfort. Quantifying the specific pressure may enable clinicians and users to determine and improve comfort levels objectively.

OBJECTIVES

(1) To evaluate if a peak pressure reduction assists in resolving wounds, redness, and pain inside prosthetic sockets in people with transtibial amputation. (2) To determine if peak pressures measured inside the prosthetic socket due to external forces could be used to quantify the level of improvement in socket discomfort.

DESIGN

In this cohort study, we used a pressure sensor to quantify and facilitate adjustments to the prosthetic socket, correlating this information to the user's socket comfort.

SETTING

Outpatient clinic in a tertiary hospital in Singapore.

PARTICIPANTS

People (N = 16) with unilateral transtibial lower limb amputation using a prosthesis.

INTERVENTIONS

NA.

MAIN OUTCOME MEASURES

Peak pressure and socket comfort score (SCS).

RESULTS

The peak pressure value showed a statistically significant reduction across all participants following adjustments at a 50% delta change in pressure (p = .001). This was achieved with a mean number of 2.6 ± 1.4 adjustments per participant. Following the adjustments, the paired t-test results showed a mean increase between the first SCS and final SCS was 2.6 (p = .001).

CONCLUSION

The wound, redness, and pain resolved in 15 of 16 participants regardless of diabetic status following socket adjustments. Although the peak pressures values did not correlate to the SCS score, the reduction in peak pressure saw significant improvement to the SCS. The use of a portable sensor is a fast and efficient means to quantify adjustments inside the prosthetic socket and could potentially be considered as part of future care delivery.

Differences in Hip Muscle Strength and Static Balance in Patients with Transfemoral Amputations Classified at Different K-Levels: A Preliminary Cross-Sectional Study

BACKGROUND

Following amputation, patients with lower limb amputations (LLA) are classified into different functional mobility levels (K-levels) ranging from K0 (lowest) to K4 (highest). However, K-level classification is often based on subjective criteria. Objective measures that are able to differentiate between K-levels can help to enhance the objectivity of K-level classification.

OBJECTIVES

The goal of this preliminary cross-sectional study was to investigate whether differences in hip muscle strength and balance parameters exist among patients with transfemoral amputations (TFA) assigned to different K-levels.

METHODOLOGY

Twenty-two participants with unilateral TFA were recruited for this study, with four participants assigned to K1 or K2, six assigned to K3 and twelve assigned to K4. Maximum isometric hip strength of the residual limb was assessed in hip flexion, abduction, extension, and adduction using a custom-made diagnostic device. Static balance was investigated in the bipedal stance on a force plate in eyes open (EO) and eyes closed (EC) conditions. Kruskal-Wallis tests were used to evaluate differences between K-level groups.

FINDINGS

Statistical analyses revealed no significant differences in the parameters between the three K-level groups (p>0.05). Descriptive analysis showed that all hip strength parameters differed among K-level groups showing an increase in maximum hip torque from K1/2-classified participants to those classified as K4. Group differences were also present in all balance parameters. Increased sway was observed in the K1/2 group compared to the K4 group, especially for the EC condition.

CONCLUSION

Although not statistically significant, the magnitude of the differences indicates a distinction between K-level groups. These results suggest that residual limb strength and balance parameters may have the potential to be used as objective measures to assist K-level assignment for patients with TFA. This potential needs to be confirmed in future studies with a larger number of participants.

Quantifying the risk of falls and injuries for amputees beyond annual fall rates-A longitudinal cohort analysis based on person-step exposure over time

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People with lower-limb loss even with community walking ability have high annual fall and injury rates.

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True fall and injury risk may be obscured if exposure to risk measured by person-steps over time is not considered.

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Risk was higher for amputees with limited walking ability per person-step exposure over time.

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Incorporating person-step exposure over time clarifies fall and injury risk level.

People with lower-limb loss (PLL) have high annual fall and injury rates. People with transtibial amputations have better walking function than those with transfemoral amputations but paradoxically incur more fall-related injuries. Risk exposure, however, has not been previously considered. This study examined whether all-cause fall and injury incidence per person-step exposure over time varied in PLL of different walking abilities. The prospective cohort design, conducted at a major medical center, included five assessments 1-month apart. Walking ability level was categorized by Houghton Scale scores: ≥9 indicating community walking and ≤ 8 indicating limited community-household walking. Accelerometer-measured daily step counts were collected via StepWatch4 monitors. The main outcome measures, self-reported all-cause falls and injuries were assessed using the standard National Health Injury Survey. Generalized estimating equations, using Poisson distributions and log of step count as an offset, determined fall and injury incidence rate ratio [IRR] according to walking ability level. Ten people, aged 33–63 years with amputations of different causes and levels, were assessed monthly over five months. The community walking group (n = 6) had six falls and seven injuries; the limited community walking group (n = 4) had four falls and three injuries. For PLL, limited community walking ability was associated with higher incidence of falls (IRR = 6.10, 95%CI = 1.12–33.33, p = 0.037) and injuries (IRR = 8.56, 95%CI = 1.73–42.40, p = 0.009) when accounting for person-steps. Considering per person-step exposure over time added precision to fall and injury risk assessment that clarified the risks: PLL with limited community walking ability have higher fall and injury risks.

User perspectives on the future of mobility assistive devices: Understanding users’ assistive device experiences and needs

Introduction

Current assistive devices are inadequate in addressing the needs of some people living with impaired mobility. This study explored the experiences of living with impaired mobility in relation to how wearable assistive adaptive and rehabilitative technologies may improve their quality of life.

Methods

A cross-case study approach was adopted; the case being defined as the experience of impaired mobility. Semi-structured interviews were utilised. The sample ( n = 8) was purposefully selected to have impaired mobility due to stroke, age-related frailty, or lower limb amputation. From the interview transcripts, in-depth case illustrations were written to provide personal stories and thematic analysis was carried out to provide a cross-case analysis.

Results

There were two overarching themes: lifestyle changes; and wishes and desires for assistive devices. There were shared experiences across participant groups, such as falls and fear of falling. All participants identified a wish for increased speed of walking. However, the reasons for their difficulties differed depending on personal factors and their condition. Participants wanted devices to be adjustable to their perceived ability on a day-to-day basis.

Conclusions

Although common concerns and impacts of living with impaired mobility were apparent, individuals have unique requirements that should inform the design of assistive technology devices.

Deleterious Musculoskeletal Conditions Secondary to Lower Limb Loss: Considerations for Prosthesis-Related Factors

Significance: The intent of this work was to summarize the existing evidence of, and highlight knowledge gaps specific to, prosthetic devices/componentry and training regimes, particularly in the context of the human-device interaction and deleterious musculoskeletal conditions secondary to lower limb loss. Recent Advances: With the recent and evolving technological advancements in prostheses, there are numerous devices available to individuals with lower limb loss. Current literature demonstrates the importance of expanding the knowledge of all prosthetic device-specific factors and the significance of proper prescription, fit, and alignment, along with adequate device-/activity-specific training, to enhance human-device interaction, reduce gait abnormalities and compensatory motions, and as a result, mitigate risk for secondary musculoskeletal conditions. Critical Issues: Inadequate device prescription, fit, alignment, and training are evident owing to the lack of knowledge or awareness of the many device-specific properties and factors, leading to suboptimal use, as well as, biomechanical compensations, which collectively and adversely affect the function, activity level, and overall health of the prosthesis user. Future Directions: To maximize optimal outcomes after lower limb loss, it is essential to better appreciate the factors that affect both prosthesis use and satisfaction, particularly any modifiable factors that might be targeted in rehabilitation interventions such as device prescription, fit/alignment, and training regimes. A better understanding of such device-specific factors will help enhance the human-device interaction and resulting functional performance, thereby reducing secondary musculoskeletal conditions, allowing for the readiness of the fighting force (return-to-duty/redeployment) and/or improved reintegration into civilian society/work, and overall enhancing quality of life after lower limb loss.

Trends and Opportunities in Health Economic Evaluations of Prosthetic Care Innovations

Overcoming obstacles to prosthetic fittings requires frequent tryouts of sockets and components. Repetitions of interventions are upsetting for users and place substantial economic burden on healthcare systems. Encouraging prosthetic care innovations capable of alleviating clinical and financial shortcomings of socket-based solutions is essential. Nonetheless, evidence of socio-economic benefits of an innovation are required to facilitate access to markets. Unfortunately, complex decisions must be made when allocating resources toward the most relevant health economic evaluation (HEE) at a given stage of development of an innovation. This paper first, aimed to show the importance and challenges of HEEs of intervention facilitating prosthetic fittings. Next, the main trends in HEEs at various phases of product development and clinical acceptance of prosthetic care innovations were outlined. Then, opportunities for a basic framework of a preliminary cost-utility analysis (CUA) during the mid-stage of development of prosthetic care innovations were highlighted. To do this, fundamental and applied health economic literature and prosthetic-specific publications were reviewed to extract and analyse the trends in HEEs of new medical and prosthetic technologies, respectively. The findings show there is consensus around the weaknesses of full CUAs (e.g., lack of timeliness, resource-intensive) and strengths of preliminary CUAs (e.g., identify evidence gaps, educate design of full CUA, fast-track approval). However, several obstacles must be overcome before preliminary CUA of prosthetic care innovations will be routinely carried out. Disparities of methods and constructs of usual preliminary CUA are barriers that could be alleviated by a more standardized framework. The paper concludes by identifying that there are opportunities for the development of a basic framework of preliminary CUA of prosthetic care innovations. Ultimately, the collaborative design of a framework could simplify selection of the methods, standardise outcomes, ease comparisons between innovations and streamline pathways for adoption. This might facilitate access to economical solutions that could improve the life of individuals suffering from limb loss.

Effects of Prosthetic Socket Design on Residual Femur Motion Using Dynamic Stereo X-Ray - A Preliminary Analysis

Individuals with transfemoral amputation experience relative motion between their residual limb and prosthetic socket, which can cause inefficient dynamic load transmission and secondary comorbidities that limit mobility. Accurately measuring the relative position and orientation of the residual limb relative to the prosthetic socket during dynamic activities can provide great insight into the complex mechanics of the socket/limb interface. Five participants with transfemoral amputation were recruited for this study. All participants had a well-fitting, ischial containment socket and were also fit with a compression/release stabilization socket. Participants underwent an 8-wk, randomized crossover trial to compare differences between socket types. Dynamic stereo x-ray was used to quantify three-dimensional residual bone kinematics relative to the prosthetic socket during treadmill walking at self-selected speed. Comfort, satisfaction, and utility were also assessed. There were no significant differences in relative femur kinematics between socket types in the three rotational degrees of freedom, as well as anterior-posterior and medial-lateral translation (p > 0.05). The ischial containment socket demonstrated significantly less proximal-distal translation (pistoning) of the femur compared to the compression/release stabilization socket during the gait cycle (p < 0.05), suggesting that the compression/release stabilization socket provided less control of the residual femur during distal translation. No significant differences in comfort and utility were found between socket types (p > 0.05). The quantitative, dynamic analytical tools used in the study were sensitive to distinguish differences in three-dimensional residual femur motion between two socket types, which can serve as a platform for future comparative effectiveness studies of socket technology.

Sex, age, and other barriers for prosthetic referral following amputation and the impact on survival

BACKGROUND

Despite advances in peripheral vascular disease treatment, lower extremity amputation continues to be necessary in a significant number of patients. Up to 80% of amputees are not referred for prosthetic fitting. The factors contributing to referral decisions have not been adequately investigated, nor has the impact of prosthetic referral on survival. We characterized differences between patients who were successfully referred to our in-house prosthetists and those who were not, and identified factors associated with prosthetic referral and predictive of survival.

METHODS

This was a retrospective analysis of all patients who underwent lower extremity amputation by surgeons in our practice from January 1, 2010, to June 30, 2017. Data regarding age, sex, race, body mass index (BMI), diabetes, hypertension, hyperlipidemia, end-stage renal disease, prior coronary artery bypass graft surgery, congestive heart failure, tobacco use, American Society of Anesthesiologists (ASA) score, previous arterial procedure, chronic obstructive pulmonary disease, statin use, postoperative ambulatory status, level of amputation, stump revision, and referral for prosthesis were collected. Survival was determined from a combination of sources, including the Social Security Death Master Index, multiple genealogic registries, and internet searches. Multivariable logistic regression was used to determine risk factors associated with prosthesis referral. Multivariable Cox proportional hazard regression with time-dependent covariates was performed to assess risk factors associated with 5-year mortality.

RESULTS

There were 293 patients included in this study. Mean age was 66 years, and mean BMI 27 kg/m². The majority of patients were male (69%), white (53%), with diabetes (65.4%) and hypertension (77.5%), and underwent below-the-knee amputation (BKA) (73%). Prosthetic referral occurred in 123 (42.0%). Overall 5-year survival was 61.7% (95% confidence interval [CI], 55.9%-68.1%) (BKA 64.7% [95% CI, 57.9%-72.3%]; above-the-knee amputation 53.8% [95% CI, 43.4%-66.6%]). On multivariate analysis, age >70 years, female sex, diabetes, ASA score 4 or 5, and current tobacco use were associated with no referral for prosthetic fitting. Patients with BMI 25 to 30, a previous arterial procedure, BKA, and history of stump revision were more likely to be referred. Factors associated with decreased survival were increasing age, higher ASA class, black race, and BMI; prosthetic referral was seen to be protective.

CONCLUSIONS

We identified multiple patient factors associated with prosthetic referral, as well as several characteristics predictive of reduced survival after amputation. Being referred for prosthetic fitting was associated with improved survival not explained by patient characteristics and comorbidities. Further research is needed to determine whether the factors identified as associated with nonreferral are markers for patient characteristics that make them clinically unsuitable for prosthetic fitting or if they are symptoms of unconscious bias or of the patient's access to care.

Design of a Single Layer Metamaterial for Pressure Offloading of Transtibial Amputees

While using a prosthesis, transtibial amputees can experience pain and discomfort brought on by large pressure gradients at the interface between the residual limb and the prosthetic socket. Current prosthetic interface solutions attempt to alleviate these pressure gradients using soft homogenous liners to reduce and distribute pressures. This research investigates an additively manufactured metamaterial inlay with a tailored mechanical response to reduce peak pressure gradients around the limb. The inlay uses a hyperelastic behaving metamaterial (US10244818) comprised of triangular pattern unit cells, 3D printed with walls of various thicknesses controlled by draft angles. The hyperelastic material properties are modeled using a Yeoh third-order model. The third-order coefficients can be adjusted and optimized, which corresponds to a change in the unit cell wall thickness to create an inlay that can meet the unique offloading needs of an amputee. Finite element analysis simulations evaluated the pressure gradient reduction from (1) a standard homogenous silicone liner, (2) a prosthetist's inlay prescription that utilizes three variations of the metamaterial, and (3) a metamaterial solution with optimized Yeoh third-order coefficients. Compared to a traditional homogenous silicone liner for two unique limb loading scenarios, the prosthetist prescribed inlay and the optimized material inlay can achieve equal or greater pressure gradient reduction capabilities. These preliminary results show the potential feasibility of implementing this metamaterial as a method of personalized medicine for transtibial amputees by creating a customizable interface solution to meet the unique performance needs of an individual patient.

Self-Management to Improve Function After Amputation: A Randomized Controlled Trial of the VETPALS Intervention

OBJECTIVE

To (1) evaluate the effects of a group-based self-management treatment intervention (VETPALS) on physical and psychosocial functioning (primary outcomes) and quality of life (secondary outcome) in individuals with amputation and (2) examine the feasibility and acceptability of the intervention in a large national health care system.

DESIGN

Randomized controlled trial with masked outcome assessment.

SETTING

Five Veterans Affairs medical centers geographically dispersed across the United States.

PARTICIPANTS

147 individuals with amputation during the past 2 years due to chronic limb threatening ischemia (N=147).

INTERVENTIONS

Participants were randomized into VETPALS (N =71) or education control (N=76). VETPALS consisted of a 4-hour workshop and 4 additional 2-hour sessions addressing self-management skills, health and activity, managing emotions, communication and social support, and maintaining goals and gains. Education control consisted of the provision of amputation-related educational materials and provider follow-up if requested.

MAIN OUTCOME MEASURES

Primary outcomes were physical functioning (Short Musculoskeletal Functional Assessment) and psychosocial functioning (Patient Health Questionnaire-9). Secondary outcomes were quality of life (global) and quality of life (satisfaction with health) from the World Health Organization Quality of Life Scale (brief). Assessment was conducted at baseline, 6 weeks (treatment completion), and 6 months (follow-up).

RESULTS

Participants randomized to VETPALS reported significantly improved psychosocial functioning and quality of life (satisfaction with health) relative to controls at 6 months (B=1.84; 95% confidence interval, 0.37,3.31 and B=-0.61; 95% confidence interval, -1.11,-0.12, respectively). There were no differences in physical functioning over time between VETPALS and education control at either time point. Follow-up multiple imputation sensitivity analyses produced an identical pattern of results. Among VETPALS participants, treatment initiation was low (56%), but treatment retention (93% attended 4 of 5 classes) and overall satisfaction (100% reported very helpful or better and would recommend to a friend) were high.

CONCLUSIONS

Group-based self-management improves psychosocial functioning for individuals with amputation due to chronic limb threatening ischemia. In-person participation is challenging for this population, but individuals who successfully initiate treatment typically persist and are highly satisfied.

The comprehensive lower limb amputee socket survey: Reliability and validity of the persian version

BACKGROUND

The Comprehensive Lower limb Amputee Socket Survey (CLASS) is a self-reported measure developed to assess prosthetic socket fit in individuals with lower limb amputation.

OBJECTIVE

To assess the reliability and validity of the Persian version of the CLASS.

STUDY DESIGN

Cross-sectional and repeated-measures.

METHODS

We evaluated the translation and back translation of the CLASS and made the required changes according to expert committee feedback. Then, we recruited 124 participants with unilateral lower limb amputation (89.5% men). Internal consistency was analyzed with Cronbach's alpha and test-retest reliability using intra-class correlation coefficients. Convergent construct validity was assessed by comparing the CLASS scores with the Persian version of the Trinity Amputation and Prosthesis Experience Scales (TAPES) scores. In addition, known groups construct validity was assessed by comparing CLASS scores between groups with different causes and levels of amputation.

RESULTS

Cronbach's alpha coefficient represented a very good internal consistency for all domains of the Persian CLASS (ranged from 0.86 to 0.92). The intra-class correlation coefficient for test-retest reliability for the Persian CLASS was good to excellent (ranged from 0.73 to 0.97). There was a significant correlation between the subscales of the Persian CLASS and satisfaction subscales of the Persian TAPES (p < 0.001). There was significant difference between comfort subscale of the Persian CLASS scores by level of amputation.

CONCLUSION

The Persian CLASS is a reliable and valid measure for evaluating prosthetic socket fit.

Quantifying Step Count and Oxygen Consumption with Portable Technology during the 2-Min Walk Test in People with Lower Limb Amputation

Step counts and oxygen consumption have yet to be reported during the 2-min walk test (2MWT) test in persons with lower-limb amputations (LLA). The purpose of this study was to determine step counts and oxygen consumption during the 2MWT in LLA. Thirty-five men and women walked for two minutes as quickly as possible while wearing activity monitors (ActiGraph Link on the wrist (LW) and ankle (LA), Garmin vivofit^®3 on the wrist (VW) and ankle (VA), and a modus StepWatch on the ankle (SA), and a portable oxygen analyzer. The StepWatch on the ankle (SA) and the vivofit3 on the wrist (VW) had the least error and best accuracy of the activity monitors studied. While there were no significant differences in distance walked, oxygen consumption (VO₂) or heart rate (HR) between sexes or level of amputation (p > 0.05), females took significantly more steps than males (p = 0.034), and those with unilateral transfemoral amputations took significantly fewer steps than those with unilateral transtibial amputations (p = 0.023). The VW and SA provided the most accurate step counts among the activity monitors and were not significantly different than hand counts. Oxygen consumption for all participants during the 2MWT was 8.9 ± 2.9 mL/kg/min, which is lower than moderate-intensity activity. While some may argue that steady-state activity has not yet been reached in the 2MWT, it may also be possible participants are not walking as fast as they can, thereby misclassifying their performance to a lower standard.

Validation and revision of the questionnaire to explore human factors and their technical potential for lower limb prosthetics

BACKGROUND

A variety of instruments exist to measure human factors for lower limb amputation and prosthesis research. Yet, there is no valid or reliable tool available that focuses on technical potentials.

OBJECTIVE

This study aimed to validate and revise the Questionnaire to Explore Human Factors and their Technical Potential.

STUDY DESIGN

Cross-sectional study METHODS:: A total of 150 persons with lower limb amputation from Germany participated in the study. Statistical properties, including Cronbach's alpha, item difficulty, item-total correlation, and distribution of missing values were calculated. Thresholds for acceptable psychometric properties were defined, unsuitable items were removed, and problematic items were reviewed regarding formulation.

RESULTS

The Cronbach's alpha for subscales within the Questionnaire to Explore Human Factors and their Technical Potential were between 0.72 and 0.89. A total of 56 items showed acceptability, and 14 items had problematic item property values. Four of those items were reformulated, five were excluded, six were left in the scale, and an additional one was added to the scale.

CONCLUSION

Evaluation of the Questionnaire to Explore Human Factors and their Technical Potential indicates it exhibits good internal consistency and acceptable psychometric properties. The scale was revised and is recommended to explore aspects of technical prosthesis development.

CLINICAL RELEVANCE

Our results show that the revised Questionnaire to Explore Human Factors and their Technical Potential may serve as a reliable and valid means, when designing prostheses, both during development and clinical evaluations and fittings, to assess the technical potential of lower limb prostheses directly according to the needs of users with lower-limb amputations.

Factors Associated With Prosthesis Embodiment and Its Importance for Prosthetic Satisfaction in Lower Limb Amputees

Perceptual integration of a prosthesis into an amputee's body representation, that is, prosthesis embodiment, has been proposed to be a major goal of prosthetic treatment, potentially contributing to the user's satisfaction with the device. However, insufficient knowledge about individual or prosthetic factors associated with prosthesis embodiment challenges basic as well as rehabilitation research. In the present study, hierarchical multiple regression analyses on prosthesis embodiment—as assessed with the recently introduced Prosthesis Embodiment Scale—were applied to the survey data of a large sample of prosthesis-using lower limb amputees, entering relevant objective-descriptive (i.e., unbiased characteristics of the amputation or the prosthesis) and subjective-evaluative variables (i.e., the amputee's perceptions related to the amputation or the prosthesis) as first- or second-level regressors, respectively. Significant regressors identified in these analyses together explained R² = 36.3% of prosthesis embodiment variance in the present sample, with a lower level of amputation, less intense residual limb pain, more realistic visual appearance of the device, higher prosthetic mobility, and more positive valence of prosthesis-induced residual limb stimulations representing significantly associated factors. Using the identical set of regressors hierarchically complemented by prosthesis embodiment on measures of prosthetic satisfaction—as assessed with the Trinity Amputation and Prosthesis Experience Scales—revealed that prosthesis embodiment was significantly and positively associated with aesthetic as well as functional prosthesis satisfaction. These findings emphasize the importance of psychological factors for the integration of a prosthesis into the amputee's body representation, which itself represents a crucial factor associated with prosthesis satisfaction. The results might have important implications for future prosthetic treatment; however, replication of the findings in an independent sample is required, as well as sophisticated experimental designs in order to elucidate the causality of effects.

Synergizing microfluidics with soft robotics: A perspective on miniaturization and future directions

Soft robotics has gone through a decade of tremendous progress in advancing both fundamentals and technologies. It has also seen a wide range of applications such as surgery assistance, handling of delicate foods, and wearable assistive systems driven by its soft nature that is more human friendly than traditional hard robotics. The rapid growth of soft robotics introduces many challenges, which vary with applications. Common challenges include the availability of soft materials for realizing different functions and the precision and speed of control required for actuation. In the context of wearable systems, miniaturization appears to be an additional hurdle to be overcome in order to develop truly impactful systems with a high user acceptance. Microfluidics as a field of research has gone through more than two decades of intense and focused research resulting in many fundamental theories and practical tools that have the potentials to be applied synergistically to soft robotics toward miniaturization. This perspective aims to introduce the potential synergy between microfluidics and soft robotics as a research topic and suggest future directions that could leverage the advantages of the two fields.

Patient’s satisfaction with a lower limb prosthesis: a longitudinal study

ABSTRACT This is a descriptive longitudinal study that aimed to verify prosthesis satisfaction of older adults with lower-limb amputation (LLA). In total, This study was composed of 34 older adults with LLA participated of this study. Participant’s satisfaction about the lower-limb prosthesis (LLP), the discomforts, and the embarrassment when use it were evaluated through an interview composed of five questions. The occurrence of falls and the independence in prosthesis management were also evaluated. All variables were collected at the last week of ambulatory rehabilitation discharge and after one and three months. A descriptive and inferential statistical analysis was performed. The level of significance was set at 5% (p <0.05). In total, 80% of participants with transtibial amputation and 78.6% of participants with transfemoral amputation were satisfied with the LLP after three months. Tight prosthesis, walking pain, the embarrassment of using LLP, and the occurrence of falls decreased over time. The independence in prosthesis handling did not change significantly after three months. Participants that used manual locking knee (p=0.040) and/or Solid-Ankle Cushion Heel foot (p=0.017) were more satisfied with LLP. The occurrence of falls reduced (p=0.039) after transfemoral participants started to use the prosthesis. Participant’s satisfaction with the LLP was high and did not change significantly over time.

Leg dominance as a determinant in laterality of lower extremity amputation in diabetic patients: retrospective study and literature review

Background/Aims

Diabetic patients with peripheral vascular manifestations often develop foot ulcers and sometimes have to undergo lower extremity amputation. This retrospective study investigated leg dominance and laterality of lower extremity amputation in diabetic, dysvascular amputees.

Methods

All patients who met the inclusion criteria had their medical records reviewed for their dominant side and a correlation with a side of amputation was analysed. This information is routinely obtained as part of the admission history. For the literature review, PubMed, Google Scholar, ScienceDirect and Cochrane Library were searched with no date restriction until February 2018. Relevant studies were included and analysed.

Results

Of all the patients (n=27), 16 had diabetes and of these, 12 (75%) had their dominant leg amputated.

Conclusions

The data and literature analysis suggest that diabetic, dysvascular patients' dominant legs may be at higher risk for amputation than the non-dominant side. Larger studies are needed to clarify the relationship between leg dominance and laterality of lower extremity amputation.

Mobility analysis of amputees (MAAT 3): Matching individuals based on comorbid health reveals improved function for above-knee prosthesis users with microprocessor knee technology

The objective of this cross-sectional observational study was to determine whether the use of a microprocessor knee for individuals with an above-the-knee amputation results in improved functional mobility compared to their peers of matched comorbid-health with a non-microprocessor knee, and to inform how this compares to the mobility observed in below-knee prosthesis users. A sample of 450 individuals with lower limb amputation were divided into three groups (n = 150 each). The groups included: nonmicroprocessor knee users (NMPK, age: 57.6 ± 17.2 years), microprocessor knee users (MPK, age: 56.5 ± 13.8 years), and below-knee prosthesis users (BKA, age: 58.4 ± 12.2 years). Primary outcome measure was functional mobility measured through Prosthetic Limb Users' Survey of Mobility (PLUS-M®). Results showed MPK mobility (48.49 ± 0.86) was greater than NMPK (43.49 ± 0.86, p < 0.001), but less than BKA (52.11 ± 0.86, p = 0.003). These results persisted when removing potential confounding effects of age, body mass index, cause of amputation, and comorbid health (MPK: 47.15 ± 0.97; NMPK: 43.47 ± 0.88; BKA: 52.61 ± 0.91). In conclusion, these results show the use of a MPK can improve functional mobility for individuals with an above-knee amputation.

Short-Term Walking Outcomes in Diabetic and Non-Diabetic Unilateral Transtibial Amputees

This study compared short-term walking outcomes in diabetic amputees after prosthesis fitting compared to that in non-diabetic amputees. We retrospectively investigated walking outcomes at 3 months after starting gait training with a prosthesis. Forty-four unilateral transtibial amputees with (n=18) and without diabetes (n=26) were included. At 3 months after gait training with a prosthesis, only 2/18 (11.1%) and 3/18 (16.7%) diabetic amputees were capable of independent outdoor and indoor walking without cane, respectively. However, 21/26 (80.8%) and 24/26 (92.3%) non-diabetic amputees were capable of independent outdoor and indoor walking without cane, respectively. With assistance of cane, most of non-diabetic amputees (n=24, 92.3%) were capable of walking in both outdoor and indoor but only seven (38.9%) and nine (50.0%) diabetic amputees were capable, respectively. Thus, short-term walking outcome were poor in transtibial amputee with diabetes compare to those without diabetes, and these results suggest intensive rehabilitation would be needed to them.

Are consumers satisfied with the use of prosthetic sports feet and the provision process? A mixed-methods study

BACKGROUND

Special feet connected to a prosthesis, prosthetic sports feet, enable athletes with a lower limb amputation to run. The selection of a prosthetic sports feet is usually based on body weight and preferred sports performance. The selection of a prosthetic sport feet is also based on clinicians who likely have limited experience due to a small number of athletes with a lower limb amputation.

HYPOTHESIS

Athletes with a lower limb amputation are not satisfied with the use and service associated with prosthetic sports feet due to a lack of prosthetic sports feet provision guidelines, poorer function of prosthetic sports feet compared to the anatomical foot and ankle, and limited experience of clinicians.

EVALUATION OF HYPOTHESIS

A mixed-methods study in 16 athletes with a lower limb amputation using a prosthetic sport foot from Össur or Otto Bock, included semi-structured interviews and quantitative analysis. Three dimensions of prosthetic sports feet were investigated: 1) use, 2) provision process, and 3) cosmetics. Qualitative data were analyzed to identify factors influencing consumer satisfaction. Quantitative data were analyzed to investigate satisfaction and perceived relative importance of the dimensions.

RESULTS

Participants were satisfied with the prosthetic sports feet use. However, they were not satisfied with the process prior to provision. The prosthetic sport feet use was perceived as the most important dimension. Sports performance was the critical element in the prosthetic sports feet use and was influenced by stability, confidence and fear, safety, focus, energy return, and comfort. Cosmetics were unimportant. Motivation to purchase the prosthetic sports feet was the key element for the prosthetic sports foot acquisition. Satisfaction about the process prior to provision was negatively influenced by poor support of professionals during rehabilitation, the complexity and duration of the purchase process, and lack of information and accessibility of prosthetic sports feet.

CONCLUSION

The most important dimension of the prosthetic sports feet was its use, which was directly influenced by performance. To further increase the satisfaction with prosthetic sports feet, clinicians should establish how to meet the desired sports performance level of athletes with a lower limb amputation. Improving the process prior to the provision process may increase satisfaction. We suggest increasing the support of professionals during rehabilitation and training through cooperation between involved services, organizing prosthetic sports feet try-out sessions, and increase the accessibility of the prosthetic sports feet. In this way, individuals with a lower limb amputation may become and stay more physically active and participate in sports.

Cost-effectiveness and budget impact of the microprocessor-controlled knee C-Leg in transfemoral amputees with and without diabetes mellitus

BACKGROUND

The safe use of a prosthesis in activities of daily living is key for transfemoral amputees. However, the number of falls varies significantly between different prosthetic device types. This study aims to compare medical and economic consequences of falls in transfemoral amputees who use the microprocessor-controlled knee joint C-Leg with patients who use non-microprocessor-controlled (mechanical) knee joints (NMPK). The main objectives of the analysis are to investigate the cost-effectiveness and budget impact of C-Legs in transfemoral amputees with diabetes mellitus (DM) and without DM in Germany.

METHODS

A decision-analytic model was developed that took into account the effects of prosthesis type on the risk of falling and fall-related medical events. Cost-effectiveness and budget impact analyses were performed separately for transfemoral amputees with and without DM. The study took the perspective of the statutory health insurance (SHI). Input parameters were derived from the published literature. Univariate and probabilistic sensitivity analyses (PSA) were performed to investigate the impact of changes in individual input parameter values on model outcomes and to explore parameter uncertainty.

RESULTS

C-Legs reduced the rate of fall-related hospitalizations from 134 to 20 per 1000 person years (PY) in amputees without DM and from 146 to 23 per 1000 PY in amputees with DM. In addition, the C-Leg prevented 15 or 14 fall-related death per 1000 PY. Over a time horizon of 25 years, the incremental cost-effectiveness ratio (ICER) was 16,123 Euro per quality-adjusted life years gained (QALY) for amputees without DM and 20,332 Euro per QALY gained for amputees with DM. For the period of 2020-2024, the model predicted an increase in SHI expenditures of 98 Mio Euro (53 Mio Euro in prosthesis users without DM and 45 Mio Euro in prosthesis users with DM) when all new prosthesis users received C-Legs instead of NMPKs and 50% of NMPK user whose prosthesis wore out switched to C-Legs. Results of the PSA showed moderate uncertainty and a probability of 97-99% that C-Legs are cost-effective at an ICER threshold of 40,000 Euro (≈ German GDP per capita in 2018) per QALY gained.

CONCLUSION

Results of the study suggest that the C-Leg provides substantial additional health benefits compared with NMPKs and is likely to be cost-effective in transfemoral amputees with DM as well as in amputees without DM at an ICER threshold of 40,000 Euro per QALY gained.

Effect of temperature-control liner materials on long-term outcomes of lower limb prosthesis use: a randomized controlled trial protocol

Background

In people living with limb loss, addressing the resulting functional deficit with prostheses increases the risk for secondary conditions such as pressure sores, impaired blood perfusion, and injuries from accidental falls. Any of those occurrences can render the prosthesis temporarily useless, making it challenging for users to engage in many activities of daily life, including work, exercise, and social participation. Many of the described issues originate at the interface between residual limb and prosthetic socket, where the objectives of sufficient weight distribution and suspension are conflicting with the necessity to facilitate heat exchange and limit contact pressure and friction.

Recently, prosthesis liners that contain phase-change material have become commercially available, holding the promise that the micro climate at the interface between the residual limb skin and the prosthetic socket can be regulated to reduce the users’ tendency to sweat. Preliminary studies on these liners indicate that the socket temperatures inside the socket stayed lower and rose slower than in conventional liners. However, the clinical relevance of those findings remains unclear.

The purpose of this study is to investigate whether longer (6+ months) periods of use of phase-change material based temperature-control liners have clinically meaningful effects.

Methods

The protocol is a double-blind longitudinal cross-over research design. A sample of trans-tibial prosthesis users are wearing their regular gel or silicone liners for six months and phase-change material liners for another six months in a randomized sequence. Their prostheses is equipped with activity monitors to detect days when they could not wear their prosthesis. In six-week intervals, individuals’ activity, physical performance, and overall prosthesis assessment is recorded using standardized methods.

Discussion

Expected results will inform prescription and reimbursement practice of phase-change material-based prosthesis liners and will help improve and economize prosthetic fitting for people with limb loss. The design and duration of the protocol, including randomization, blinding, and within-subject comparison, will generate scientific evidence of a comparably high level. Inclusion of a comparably large sample and different climates, e.g. across all four seasons, will make findings applicable to a large number of prosthesis users.

Trial registration

Clinicaltrials.gov, NCT03428815. Registered on 12 February 2018.