Effects of a microprocessor-controlled ankle-foot unit on energy expenditure, quality of life, and postural stability in persons with transtibial amputation: An unblinded, randomized, controlled, cross-over study.

BACKGROUND: Microprocessor-controlled prostheses are designed to improve mobility and quality of life through better balance and energy restoration in persons with transtibial amputation. Quasi-active microprocessor-controlled ankles (MPA) adapt to variable terrain by ankle angle adjustment. OBJECTIVES: To compare energy expenditure, balance, quality of life, and satisfaction of Proprio-foot® (a quasi-active MPA model) with standard prescribed ankle prosthesis (prescribed ankle-foot units [PA]) (standard energy storage and return prosthesis). STUDY DESIGN: Multicenter, unblinded, randomized, controlled, cross-over study. METHODS: Energy expenditure (primary outcome) was assessed by oxygen uptake (VO2) measured at the maximum level reached with the 2 prostheses during treadmill walking at progressively increasing incline and speed. Balance was assessed by stabilometry in different static positions. Quality of life and satisfaction were assessed by "Short Form 36" questionnaire (0-100) and by Evaluation de la Satisfaction envers une Aide Technique (0-5) questionnaires after wearing each of the 2 prostheses for 34 days. RESULTS: Forty-five patients tested the 2 prostheses. No statistical difference in VO2 was observed. Significant improvement of balance was observed both during standing on an incline or decline with MPA and PA (p < 0.01). Short Form 36 questionnaire physical scores and Short Form 36 questionnaire mental scores were 68.5 ± 19.5 vs. 62.1 ± 19.6 (p < 0.01) and 72.0 ± 20.8 vs. 66.2 ± 20.9 (p < 0.01) in MPA and PA, respectively. Evaluation de la Satisfaction envers une Aide Technique score on the device was not statistically significant between the 2 groups (MPA 4.4 ± 0.5 vs. PA 4.3 ± 0.5, p = 0.360). CONCLUSION: Proprio-foot® improved balance, quality of life, and patient satisfaction despite no reduction or increase in energy expenditure in comparison with standard energy storage and return prosthesis.

Improving outcomes for amputees: The health-related quality of life and cost utility analysis of osseointegration prosthetics in transfemoral amputees.

AIM: Some amputees are unable to adequately ambulate using conventional socket prosthetics, osseointegrated prosthetics have been described as an alternative strategy in this patient group. This paper aims to assess the effect of osseointegrated prosthetics, commonly simply referred to as osseointegration, in transfemoral amputees on health-related quality of life and cost analysis. METHODS: Two centre analysis of patients receiving transcutaneous femoral osseointegration using The Osseointegration Group of Australia Osseointegration Prosthetic Limb (OGAP-OPL) implant. Retrospective health utility and cost analysis of prospectively collected patient reported health outcome data. Osseointegration cost was compared with the yearly cost of a poorly fitting conventional prosthetic determining cost/Quality Adjusted Life Year. RESULTS: Eighty amputees received osseointegration. Mean age was 39 years (range 20-57) and 66% were male (n = 53). The majority of subjects underwent unilateral (n = 62, 77.5%) rather than bilateral surgery (n = 18, 22.5%). Trauma was the most common indication (n = 59, 74%). Maximum follow up was 10.5-years. Mean preoperative EQ5D HUV in pooled data was 0.64 (SEM 0.025) increasing to 0.73 (0.036) at 5-years and 0.78 (0.051) at 6 years with continued improvement up to 10.5-years. In subgroup analysis those with a starting EQ5D HUV <0.60 reached a cost/QALY of <£30,000 at 5-years postoperatively and show statistically significant improvement in EQ5D HUV. The UK military experience was wholly positive with a mean starting EQ5D HUV of 0.48 (0.017) with significant (p < 0.05) improvement in EQ5D HUV at each time point and a resultant reducing cost/QALY at each time point being £28,616.89 at 5 years. CONCLUSION: There is both a quality of life and financial argument in favour of osseointegration in select patients with above transfemoral amputations. In those unable to mobilise satisfactorily with traditional prostheses and a pre-intervention score of <0.60, a consistent cost effectiveness and quality of life benefit can be seen. Such patients should be considered for osseointegration as these patients reap the maximum benefit and cost effectiveness of the device. This evidence lends strongly to the debate advocating the use of osseointegration through centrally funded resources, including the NHS.

Can microprocessor knees reduce the disparity in trips and falls risks between above and below knee prosthesis users?

While all lower limb prosthesis walkers have a high risk of tripping and/or falling, above knee prosthesis users are reported to fall more frequently. Recognising this, engineers designed microprocessor knees (MPK) to help mitigate these risks, but to what extent these devices reduce this disparity between above and below knee users is unclear. A service review was carried out in a prosthetic limb centre regarding the frequency of trips and falls in the previous four weeks. Data from unilateral, community ambulators were extracted. Ordered logistic regressions were applied to investigate whether MPKs mitigated the increased risk of trips and falls for prosthetic knee users, compared to below knee prosthesis users. Socio-demographics (sex, age), prosthesis (prosthesis type, years of use), health (comorbidities, vision, contralateral limb status, medication), and physical function (use of additional walking aids, activity level) were included as covariates. Of the 315 participants in the analysis, 57.5% reported tripping and 20.3% reported falling. Non-microprocessor prosthetic knee (non-MPK) users were shown to trip significantly more than below knee prosthesis users (OR = 1.96, 95% CI = 1.17-3.28). Other covariates showing a significant association included contralateral limb injuries (OR = 1.91, 95% CI = 1.15-3.18) and using an additional walking aid (OR = 1.99, 95% CI = 1.13-3.50). Non-MPK users were also shown to fall significantly more than below knee prosthesis users (OR = 3.34, 95% CI = 1.73-6.45), with no other covariates showing a significant association. MPK users did not show an increased frequency of trips (OR = 0.74, 95% CI = 0.33-1.64) or falls (OR = 0.34, 95% CI = 0.18-2.62), compared to below knee prosthesis users. Of those who tripped at least once in the previous four weeks, those using a non-MPK (OR = 2.73, 95% CI = 1.30-5.74) presented an increased frequency of falling. These findings provide evidence to suggest that the use of MPKs reduces the difference in falls risk between above knee and below knee prosthesis users, providing justification for their provision.

A Better Framework for the Assessment of Performance and Stability of Co-Adaptive Myoelectric Systems.

Co-adaptive myoelectric human-machine systems are a fairly recent, but promising, advancement in pattern recognition-based myoelectric control. Their performance and stability, however, are not fully understood due in part to a lack of proper assessment tools. Time-series based analyses are typically used despite the availability of techniques used in other fields that can robustly measure stability and performance. In this research, we leverage the success achieved by lower limb systems to improve the assessment framework of co-adaptive myoelectric systems by exploiting a key feature common between the two systems. The cyclical dynamics found in lower limbs are also apparent in co-adaptive myoelectric systems, allowing us to analyze their behavior using Poincaré maps. A 10-day experiment was designed and conducted to observe the effects of algorithm adaptation and myoelectric experience level on the performance of a co-adaptive myoelectric control system. Through Poincaré maps, we were able to identify learning effects, as well as oscillations and uncertainty in performance. Assessment of these seemingly random variations in performance led to the inference that co-adaptive systems can be chaotic. Modelling co-adaptive myoelectric systems as cyclical leads to the application of an improved framework to better assess and describe their dynamics and performance.

Assessment of Socket Pressure during Walking in Rapid Fit Prosthetic Sockets.

(1) Background: A sustainable casting system that combines the use of a polystyrene bag, a prosthetic liner and a vacuum system was developed to reduce fabrication time while maintaining comfort for the trans-tibial prosthesis user. (2) Methods: Eight prosthetists (28.7 ± 8.25 years old) fit ten trans-tibial prosthesis wearers (46 ± 12.4 years old) with two types of total surface bearing (TSB) prostheses; a polystyrene bead (PS) prosthesis and a plaster of paris (POP) prosthesis. Duration of casting and combined mean peak pressure was measured at six locations on the residual limb using Force Sensing Resistors (FSR). A pressure uniformity score (%) was determined. Socket Comfort Scale (SCS) was also measured. (3) Results: Duration of casting for the POP method was 64.8 ± 9.53 min and 7.8 ± 2 min for the PS method, (p = 0.006). Pressure uniformity in the POP prosthesis was 79.3 ± 6.54 and 81.7 ± 5.83 in the PS prosthesis (p = 0.027). SCS in both prosthesis types were equivalent. (4) Conclusion: A rapid fit PS prosthesis was developed, with significantly shorter duration than the traditional POP method. Socket pressure uniformity was confirmed and improved in the PS method. Socket comfort was equal between the two prothesis types.

Development of a finite element-based model for the thermal assessment of transtibial prosthetic liners.

BACKGROUND: Thermal discomfort because of elevated residual limb skin temperatures and/or perspiration within the prosthetic socket is frequently reported among people with amputation. OBJECTIVE: To evaluate the impact of the thermal conductivity characteristics of prosthetic liners on transtibial prosthesis heat dissipation, following postactivity rest. STUDY DESIGN: Time-dependent heat transfer study in solids using finite element analysis. METHODS: A three-dimensional model of the transtibial residual limb was developed by simplifying the geometry to tapered, layered cylinders. Four prosthetic socket liners of varying thermal conductivities were then added to the exterior, and the final surface temperatures of the skin layer were analyzed. RESULTS: Warmer temperatures were observed near regions with greater muscle volume; cooler temperatures were observed at the distal end of the simplified model. The final residual limb skin temperatures for each prosthetic liner were found to be significantly different from one another. Overall, the average final surface temperatures of the skin layer at the end of postactivity rest was 3.85°C ± 0.12°C greater than the initial surface temperatures of skin layer. CONCLUSIONS: None of the prosthetic liners made a significant reduction in residual limb skin temperatures after activity. The results indicate that the focus should be on other material properties of the prosthetic liners or active cooling systems.

Cost-effectiveness analysis of prosthesis provision for patients with transfemoral amputation in Tanzania.

BACKGROUND: Limb loss leads to significant disability. Prostheses may mitigate this disability but are not readily accessible in low- and middle-income countries (LMICs). Cost-effectiveness data related to prosthesis provision in resource-constrained environments such as Tanzania is greatly limited. OBJECTIVES: This study aimed to compare the cost-effectiveness of a prosthesis intervention compared with that of no prosthesis for persons with transfemoral amputations in an LMIC. STUDY DESIGN: This is a prospective cohort study. METHODS: Thirty-eight patients were prospectively followed up. Clinical improvement with prosthesis provision was measured using EuroQuol-5D, represented as quality-adjusted life years gained. Direct and indirect costs were measured. The primary outcome was incremental cost per quality-adjusted life year, measured at 1 year and projected over a lifetime using a Markov model. Reference case was set as a single prosthesis provided without replacement from a payer perspective. Additional scenarios included the societal perspective and replacement of the prosthesis. Uncertainty was measured with one-way probabilistic sensitivity analysis. RESULTS: From the payer perspective, the incremental cost-effectiveness ratio (ICER) was $242 for those without prosthetic replacement over a lifetime, and the ICER was $390 for those with prosthetic replacement over a lifeime. From the societal perspective, prosthesis provision was both less expensive and more effective. One-way sensitivity analysis demonstrated the ICER remained below the willingness to pay threshold up to prosthesis costs of $763. CONCLUSIONS: These findings suggest prosthesis provision in an LMIC may be cost-effective, but further studies with long-term follow up are needed to validate the results.

Metabolic cost of transport and stance time asymmetry in individuals with unilateral transtibial amputation using a passive prostheses while walking.

BACKGROUND: People with unilateral amputation typically walk with greater metabolic cost than able-bodied individuals, while preferring asymmetric walking characteristics. It is unclear if asymmetric walking is energetically optimal and how metabolic cost accounts for asymmetric patterns in people with amputation. The purpose of this study was to determine the effects of stance-time asymmetry on the metabolic cost of transport. METHODS: Fourteen participants (seven with amputation) completed two laboratory sessions where they walked on a treadmill while receiving real-time visual feedback about stance-time asymmetry. Expired gases were collected to determine the metabolic cost for a range of asymmetries (-15% to +15% in 5% increments, positive percentages represent more time on intact [dominant] limb). FINDINGS: Participants with amputation walked with greater (P = 0.008) stance-time asymmetry (4.34 ± 1.09%) compared with able-bodied participants (0.94 ± 2.44%). Stance-time asymmetry had a significant effect on metabolic cost (P < 0.001). The asymmetries coinciding with the predicted minimum metabolic cost for people with (3.23 ± 2.90%) and without (1.81 ± 2.18%) amputation were not different from preferred asymmetries (P = 0.365; p = 0.513), respectively. The cost of symmetric walking was 13.6% greater than near preferred walking for people with amputation (5% more time on intact limb). INTERPRETATION: Metabolic cost is not the only objective of walking, but like able-bodied individuals, it may influence how people with amputation walk. Rehabilitation typically tries to restore inter-limb symmetry after an injury, yet if the limbs are asymmetric, symmetric gait may not be optimal with current assistive devices.

Is there a trade-off between economy and task goal variability in transfemoral amputee gait?

BACKGROUND: Energy cost minimization has been widely accepted to regulate gait. Optimization principles have been frequently used to explain how individuals adapt their gait pattern. However, there have been rare attempts to account for the role of variability in this optimization process. Motor redundancy can enable individuals to perform tasks reliably while achieving energy optimization. However, we do not know how the non-goal-equivalent and goal-equivalent variability is regulated. In this study, we investigated how unilateral transfemoral amputees regulate step and stride variability based on the task to achieve energy economy. METHODS: Nine individuals with unilateral transfemoral amputation walked on a treadmill at speeds of 0.6, 0.8, 1.0, 1.2 and 1.4 m/s using their prescribed passive prostheses. We calculated the step-to-step and stride-to-stride variability and applied goal equivalent manifold (GEM) based control to decompose goal-equivalent and non-goal-equivalent manifold. To quantify the energy economy, the energy recovery rate (R) was calculated based on potential energy and kinetic energy. Comparisons were made between GEM variabilities and commonly used standard deviation measurements. A linear regression model was used to investigate the trade-off between R and GEM variabilities. RESULTS: Our analysis shows greater variability along the goal-equivalent manifold compared to the non-goal-equivalent manifold (p < 0.001). Moreover, our analysis shows lower energy recovery rate for amputee gait compared to nonamputee gait (at least 20% less at faster walking speed). We found a negative relationship between energy recovery rate and non-goal-equivalent variability. Compared to the standard deviation measurements, the variability decomposed using GEM reflected the preferred walking speed and the limitation of the passive prosthetic device. CONCLUSION: Individuals with amputation cleverly leverage task redundancy, regulating step and stride variability to the GEM. This result suggests that task redundancy enables unilateral amputees to benefit from motor variability in terms of energy economy. The differences observed between prosthetic step and intact step support the development of prosthetic limbs capable of enhancing positive work during the double support phase and of powered prosthesis controllers that allow for variability along the task space while minimizing variability that interferes with the task goal. This study provides a different perspective on amputee gait analysis and challenges the field to think differently about the role of variability.

Applying Health Utility Outcome Measures and Quality-Adjusted Life-Years to Compare Hand Allotransplantation and Myoelectric Prostheses for Upper Extremity Amputations.

BACKGROUND: An amputation of the upper extremity not only is devastating for the patient's physical, emotional, and social well-being but also constitutes a financial stress for both the patient and the health care system. The objective of this study was to determine the utility and quality-adjusted life-years of hand allotransplantation versus myoelectric prostheses and to compare these measures in patients afflicted with unilateral versus bilateral amputations. METHODS: A survey was administered on bilateral amputees, unilateral amputees, replantation patients, and healthy controls. Patient demographics, functional patient-reported outcomes, quality-of-life questionnaires, and utility outcome measures were calculated for four different scenarios: hand transplantation and myoelectric prostheses with or without complications. RESULTS: Five bilateral amputees, 12 unilateral amputees, nine replantation patients, and 45 healthy controls completed the survey. The highest quality-adjusted life-years were obtained in the replantation patient group for the scenario of myoelectric prosthesis without complications (mean, 34.8 years). Altogether, there was no statistically significant difference between hand transplantation and myoelectric prostheses (p = 0.36). On subgroup analysis, unilateral amputees reported significantly higher quality-adjusted life-years for myoelectric prostheses rather than hand transplantation (6.4; p = 0.0015), whereas bilateral amputees did not demonstrate a significant difference (-2.4; p = 0.299). CONCLUSIONS: Utility and quality-adjusted life-years do not differ significantly between hand transplantation and myoelectric prostheses, except in unilateral amputees with myoelectric prostheses, who had higher quality-of-life scores. Based on trends from this pilot study, myoelectric prostheses may be considered for unilateral amputees, whereas no superiority can be demonstrated between both treatments in bilateral amputees. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Effects of prosthetic feet on metabolic energy expenditure in people with transtibial amputation: A systematic review and meta-analysis.

OBJECTIVE: To assess the effects of different prosthetic feet on energy costs associated with walking and running in people with transtibial amputation. LITERATURE SURVEY: The Pubmed, CINAHL, and Web-of-Science bibliographic databases were searched for original research published through June 30, 2018. References from identified articles were also reviewed. METHODOLOGY: Two reviewers screened titles, abstracts, and articles for pertinent studies. Details were extracted with a standardized template. Risk of bias was assessed using domain-based methods. Prosthetic feet were grouped into categories and compared according to energy costs associated with walking or running over various terrain conditions. Meta-analyses were conducted when data quantity and homogeneity permitted. Evidence statements were formed when results were consistent or undisputed. SYNTHESIS: Fifteen studies were included. Participants (n = 141) were predominantly male (87.9%), had unilateral amputation (95.7%) from non-dysvascular causes (87.9%), and were classified as unlimited community ambulators or active adults (56.0%). Participants were often young but varied in age (mean age 24.8-66.6 years). Available evidence indicates that feet with powered dorsiflexion reduce energy costs relative to dynamic response feet in unlimited community ambulators or active adults when walking on level or declined surfaces. Dynamic response feet do not significantly reduce energy costs compared to energy storing, flexible keel, or solid ankle feet when walking on level terrain. Running feet do not reduce energy costs relative to dynamic response in active adults when running. Select feet may reduce energy costs under specific conditions, but additional research is needed to confirm preliminary results. CONCLUSIONS: The overall body of evidence is based on small samples, comprised mostly of participants who may not well represent the population of prosthesis users and test conditions that may not well reflect how prostheses are used in daily life. However, evidence suggests energy costs are affected by prosthetic foot type only under select conditions.

An exploration of specialist clinicians' experiences and beliefs about inpatient amputee rehabilitation as a pathway option for adult primary amputees.

PURPOSE: To explore specialist amputee physiotherapists' experiences and subsequent views about specialist inpatient rehabilitation (IPR) as a National Health Service (NHS) pathway option for adult primary amputees and their perceptions and beliefs about the effects of inpatient amputee rehabilitation. MATERIALS AND METHODS: A qualitative study using a phenomenological approach. Semi-structured interviews were completed with seven physiotherapists experienced in working in both specialist amputee inpatient and outpatient rehabilitation settings. Interviews were audio-recorded and fully transcribed. Data were analysed using thematic analyses; inductive coding was completed; emerging themes are shown and a conceptual framework was developed. To promote rigour, this study was peer reviewed and coding was done by two people. RESULTS: Clinicians believed inpatient amputee rehabilitation to be the preferred model of rehabilitation for the majority of adult primary amputees. A central theme of healthcare inequality within primary amputee rehabilitation provision emerged with four sub-themes: IPR, outpatient rehabilitation, barriers, the ideal world. Geographical variation was described in: type of rehabilitation provided, timescales of prosthetic rehabilitation provision, fitting a prosthesis with wounds, and the availability of community rehabilitation services. CONCLUSIONS: Healthcare inequality is a central concern identified by clinicians who work within amputee rehabilitation in the UK. Clinicians interviewed believe NHS specialist amputee inpatient rehabilitation should be a more accessible pathway.Implications for rehabilitationClinicians believe healthcare inequality exists within primary amputee rehabilitation provision in the UK National Health Service (NHS).Geographical variation in type of care provision, fitting a prosthesis with wounds, timescales in prosthetic rehabilitation provision and community rehabilitation services were described.Clinicians believe inpatient amputee rehabilitation to be the preferred model of care for the majority of adult primary amputees and should be a more accessible pathway within the NHS.Inpatient rehabilitation facilities may be a way of compensating for amputee rehabilitation inequalities.

[Correlation among tests and functional assessment scales in the follow-up of prosthetic adaptation in people with lower limb amputation]. / Correlación entre pruebas y escalas de valoración funcional en el seguimiento a la adaptación protésica de personas con amputación de miembro inferior.

INTRODUCTION: There is a wide variety of functional tests and scales for the assessment of different aspects in the adaptation of amputees, but there is still no consensus on which are the most appropriate. OBJECTIVES: To describe the measures of correlation and association among three functional tests for lower-limb amputees and to define the most appropriate for this assessment. To assess general satisfaction in lower-limb prostheses users and its association with the functional tests. METHODS: We included 83 unilateral lower-limb amputees who were users of low-cost exoskeletal prostheses. The instruments employed were the Houghton scale, the Prosthesis Evaluation Questionnaire - Mobility Scale (PEQ-MS) and the 2-minute walk test (2MWT). The statistical analysis was performed using the chi-square test and Spearman's correlation coefficient. RESULTS: The functional tests evaluated had an acceptable correlation and association with each other, but the Spearman correlation between the Houghton scale and the 2MWT was of greater significance (whole sample: r=0.56; below-knee amputees: r=0.53). The association measures did not achieve statistically significant results for above-knee amputees or for general satisfaction. CONCLUSIONS: The Houghton Scale and the 2MWT showed a good correlation and association with each other, becoming possible first-line instruments for the follow-up of exoskeletal lower limb prosthesis users. No significant association was identified between satisfaction and the instruments measured.

Model Based Design of a Low Cost and Compliant Low Profile Prosthetic Foot.

This paper describes the design of a simple and low-cost compliant low-profile prosthetic foot based on a cantilevered beam of uniform strength. The prosthetic foot is developed such that the maximum stress experienced by the beam is distributed approximately evenly across the length of the beam. Due to this stress distribution, the prosthetic foot exhibits compliant behavior not achievable through standard design approaches (e.g., designs based on simple cantilevered beams). Additionally, due to its simplicity and use of flat structural members, the foot can be manufactured at low cost. An analytical model of the compliant behavior of the beam is developed that facilitates rapid design changes to vary foot size and stiffness. A characteristic prototype was designed and constructed to be used in both a benchtop quasi-static loading test as well as a dynamic walking test for validation. The model predicted the rotational stiffness of the prototype with 5% error. Furthermore, the prototype foot was tested alongside two commercially available prosthetic feet (a low profile foot and an energy storage and release foot) in level walking experiments with a single study participant. The prototype foot displayed the lowest stiffness of the three feet (6.0, 7.1, and 10.4 Nm/deg for the prototype foot, the commercial low profile foot, and the energy storage and release foot, respectively). This foot design approach and accompanying model may allow for compliant feet to be developed for individuals with long residual limbs.

Metabolic Cost and Performance of Athletes With Lower Limb Amputation and Nonamputee Matched Controls During Running: A Systematic Review.

ABSTRACT: The elastic function of running-specific prostheses likely contributes to a lower metabolic cost of running. However, it remains unclear whether running-specific prostheses provide advantages concerning the metabolic cost of running in relationship with nonamputee runners. This study aimed to systematically review the scientific literature to examine the peak performance (peak oxygen consumption-VO2peak and peak speed) and the metabolic cost between paired amputees and nonamputees during running and between amputee runners with traditional prostheses and running-specific prostheses. A literature search on three databases (MEDLINE/PubMed, Scopus, and Web of Science) was conducted using the following key words: (amputation OR amputee) AND (run OR running OR runner) AND (prosthesis OR prosthetics), resulting in 2060 records and 4 studies within the inclusion criteria. A methodological quality assessment was carried out using a modified version of the Downs and Black checklist. VO2peak of the amputees athletes (54 ± 2 mL kg-1 min-1) is similar (mean difference = -0.80 mL kg-1 min-1, confidence interval = -4.63 to 3.03) to nonamputees athletes (55 ± 2 mL kg-1 min-1). The average metabolic cost of the paired amputee athletes (4.94 ± 1.19 J kg-1 m-1) also does not differ (mean difference = 0.73 J kg-1 m-1, confidence interval = -0.74 to 2.20) from nonamputee runners (4.21 ± 0.16 J kg-1 m-1). The research on running in amputee and nonamputee athletes is limited. The few existing studies have limited methodological quality. The metabolic cost data from amputee athletes running with running-specific prostheses are within the range of nonamputee data.

Strength testing of low-cost 3D-printed transtibial prosthetic socket.

Measurement and production of traditional prosthetic sockets are time-consuming, labor-intensive, and highly dependent on the personnel involved. An alternative way to make prostheses is using computer-aided design (CAD) and computer-aided manufacturing (CAM). Fused Filament Fabrication (FFF) may be an alternative to make low-cost prosthetic sockets. This study investigates the tensile properties of potential printing materials suitable for FFF according to ISO527 (Standard Test Method for Tensile Properties of Plastics). To ensure that FFF-printed sockets are safe for patient usage, the structural integrity of the 3D-printed prosthesis will be investigated according to ISO10328 (International Standard Structural Testing of Lower Limb Prostheses). Tough PLA was the most suitable print material according to ISO 527 testing. The Tough PLA printed socket completed 2.27 million cycles and a static test target value of 4025 N. Future research remains necessary to continue testing new potential materials, improve print settings, and improve the socket design for the production of FFF-printed transtibial prosthetic sockets. FFF using Tough PLA can be used to create transtibial prostheses that almost comply with the International Standard for Structural Testing of Lower Limb Prostheses.

General estimates of the energy cost of walking in people with different levels and causes of lower-limb amputation: a systematic review and meta-analysis.

BACKGROUND: Energy cost of walking (ECw) is an important determinant of walking ability in people with a lower-limb amputation. Large variety in estimates of ECw has been reported, likely because of the heterogeneity of this population in terms of level and cause of amputation and walking speed. OBJECTIVES: To assess (1) differences in ECw between people with and without a lower-limb amputation, and between people with different levels and causes of amputation, and (2) the association between ECw and walking speed. STUDY DESIGN: Systematic review and meta-analysis. METHODS: We included studies that compared ECw in people with and without a lower-limb amputation. A meta-analysis was done to compare ECw between both groups, and between different levels and causes of amputation. A second analysis investigated the association between self-selected walking speed and ECw in people with an amputation. RESULTS: Out of 526 identified articles, 25 were included in the meta-analysis and an additional 30 in the walking speed analysis. Overall, people with a lower-limb amputation have significantly higher ECw compared to people without an amputation. People with vascular transfemoral amputations showed the greatest difference (+102%) in ECw. The smallest difference (+12%) was found for people with nonvascular transtibial amputations. Slower self-selected walking speed was associated with substantial increases in ECw. CONCLUSION: This study provides general estimates on the ECw in people with a lower-limb amputation, quantifying the differences as a function of level and cause of amputation, as well as the relationship with walking speed.

Design of a stepwise safety protocol for lower limb prosthetic risk management in a clinical investigation.

In research on lower limb prostheses, safety during testing and training is paramount. Lower limb prosthesis users risk unintentional loss of balance that can result in injury, fear of falling, and overall decreased confidence in their prosthetic leg. Here, we present a protocol for managing the risks during evaluation of active prosthetic legs with modifiable control systems. We propose graded safety levels, each of which must be achieved before advancing to the next one, from laboratory bench testing to independent ambulation in real-world environments.

Functional Assessment of 3D Printed Prosthesis in Children with Congenital Hand Differences-A Prospective Observational Study.

Background: Children with congenital differences who require prosthesis, have special needs due to their growth and psychosocial factors. Cosmetic or body-powered prosthesis provides basic functional needs but poses a financial burden on the family. Prostheses with advanced functions need to be deferred until adulthood. 3D printed prosthesis is a novel alternative being cost-effective for children. Since limited literature is available on the functionality of 3D printed prosthesis and none in the South Asian population, this study was done to assess its utility in congenital hand amputations. Methods: Fourteen children with congenital hand amputations were selected for a prospective observational study. Unilateral below Elbow test (UBET), Box and Block test and ABILHAND questionnaire were used for assessment with and without prosthesis after six months. Results: Eleven patients completed the follow-up. Box and Block test improved from a mean score of 24 to 35 with the prosthesis implying an improvement in manual gross dexterity (p -0.049). UBET (p -0.002) and ABILHAND questionnaire (p < 0.001) showed a decrease in score with the use of a prosthesis which suggested a lack of lateral and tripod pinch in the current design of a prosthesis. Patients with below elbow prosthesis performed better. Conclusions: 3D printed prostheses are an excellent option for use as a transitional prosthesis as they are inexpensive, serves to improve needs with respect to grasping activities at both wrist and elbow level amputation and customizable according to patients' need and limb deficiency and replaceable as the child grows with age. Current designs are useful with respect to grasping activities.