Prosthetics in the developing world: a review of the literature

A Review of Natural Fiber-Reinforced Composites for Lower-Limb Prosthetic Designs

This paper presents a comprehensive review of natural fiber-reinforced composites (NFRCs) for lower-limb prosthetic designs. It covers the characteristics, types, and properties of natural fiber-reinforced composites as well as their advantages and drawbacks in prosthetic designs. This review also discusses successful prosthetic designs that incorporate NFRCs and the factors that make them effective. Additionally, this study explores the use of computational biomechanical models to evaluate the effectiveness of prosthetic devices and the key factors that are considered. Overall, this document provides a valuable resource for anyone interested in using NFRCs for lower-limb prosthetic designs.

Open-Source 3D Printing in the Prosthetic Field—The Case of Upper Limb Prostheses: A Review

Upper limb loss alters individuals’ private and professional life. Prosthetic devices are thus a solution to supply the missing upper limb segments. Nevertheless, commercial prostheses are often unaffordable, or inaccessible, to underprivileged individuals (e.g., no health insurance, low incomes, warzone). Among potential affordable alternatives, additive manufacturing, commonly “3D printing”, has been increasingly employed. This technology offers higher availability and accessibility, and can produce complex geometrical and highly customized products, which are essential features for prostheses manufacturing. Therefore, this study aims to portray an overview of reliable open-source upper limb 3D-printed prostheses currently available. We thus searched the scientific literature and online repositories hosting 3D-printable designs. We extracted data relative to mechanical and kinematic properties, 3D printing process and efficacy for each device. We found six studies implementing open-source 3DP upper limb prostheses and twenty-five open-source designs from online databases meeting selection criteria. Devices’ technical specifications were not systematically reported. In conclusion, though open-source 3D-printed upper limb prostheses can perform some functional tasks and grasps, and are widely employed to supply limb differences, further research is mandatory to validate their usage and to prove their clinical efficacy. More guidelines are required to unify contributions from private makers and non-governmental organizations with scientific groups.

Impact of prostheses on quality of life and functional status of transfemoral amputees in Tanzania

Background

The rise of diabetes and traumatic injury has increased limb loss-related morbidity in low- and middle-income countries (LMICs). Despite this, the majority of amputees in LMICs have no access to prosthetic devices, and the magnitude of prosthesis impact on quality of life (QOL ) and function has not been quantified.

Objectives

Quantify the impact of prostheses on QOL and function in Tanzanian transfemoral amputees.

Method

A prospective cohort study was conducted. Transfemoral amputees at Muhimbili Orthopaedic Institute were assessed twice before and three times after prosthetic fitting using EuroQol-5D-3L (EQ-5D-3L), Prosthetic Limb Users Survey of Mobility (PLUS-M), 2-minute walk test (2MWT) and Physiologic Cost Index (PCI). Data were analysed for change over time. Subgroup analysis was performed for amputation aetiology (vascular or non-vascular) and prosthesis use.

Results

Amongst 30 patients, EQ-5D, PLUS-M and 2MWT improved after prosthesis provision (p < 0.001). EuroQol-5D increased from 0.48 to 0.85 at 1 year (p < 0.001). EuroQol-5D and 2MWT were higher in non-vascular subgroup (p < 0.030). At 1-year, 84% of non-vascular and 44% of vascular subgroups reported using their prosthesis (p = 0.068).

Conclusion

Prosthesis provision to transfemoral amputees in an LMIC improved QOL and function. This benefit was greater for non-vascular amputation aetiologies. Quality of life and function returned to pre-prosthesis levels with discontinued use of prosthesis.

Design and Validation of a Real-Time Visual Feedback System to Improve Minimum Toe Clearance (mTC) in Transfemoral Amputees

Tripping is accompanied by reduced minimum toe clearance (mTC) during the swing phase of gait. The risk of fall due to tripping among transfemoral amputees is nearly 67% which is greater than the transtibial amputees. Therefore, intervention to improve mTC can potentially enhance the quality of life among transfemoral amputees. In this paper, we first develop a real-time visual feedback system with center of pressure (CoP) information. Next, we recruited six non-disabled and three transfemoral amputees to investigate the effect on mTC while participants were trained to shift the CoP anteriorly/posteriorly during heel strike. Finally, to assess the lasting effect of training on mTC, retention trials were conducted without feedback. During feedback, posterior shift in the CoP improved the mTC significantly from 4.68 ± 0.40 cm to 6.12 ± 0.68 cm (p < 0.025) in non-disabled participants. A similar significant improvement in mTC from 4.60 ± 0.55 cm to 5.62 ± 0.57 cm was observed in amputees during posterior shift of CoP. Besides mTC, maximal toe clearances, i.e., maxTC₁ and maxTC₂, also showed a significant increase (p < 0.025) during the posterior shift of CoP in both the participants. Moreover, during retention, mTC did not differ significantly (p > 0.05) from feedback condition in amputee, suggesting a positive effect of feedback training. The foot-to-ground angle (FGA) at mTC increased significantly (p < 0.025) during posterior shift feedback in non-disabled suggests active ankle dorsiflexion in increasing mTC. However, in amputees, FGA at mTC did not differ significantly during both anterior and posterior CoP shift feedback. The present findings suggest CoP feedback as a potential strategy during gait rehabilitation of transfemoral amputees.

A review of history of CAD/CAM system application in the productionof transtibial prosthetic socket in developing countries (from 1980to 2019)

The development of the CAD/CAM (Computer-aided design and computer-aided manufacturing) system has globally changed the fabrication and delivery of prosthetics and orthotics. Furthermore, since the introduction of CAD/CAM in the 1980s, many successful CAD/CAM system are available in the market today. However, less than 20% of amputees have access to digital fabrication technology and large portion of the amputees are from the developing countries. This review designed to examine selected studies from 1980 to 2019 on CAD/CAM systems in the production of transtibial prosthetic sockets. A review was conducted based on articles gathered from Web of Science, Pubmed and Science Direct. From the findings, 92 articles found related to CAD/CAM-derived transtibial prosthetic socket (TPS). After a further screening of the articles, 20 studies were chosen and only one study was done in a developing country. The results showed an increase interest in CAD/CAM application in Transtibial prosthetic socket (TPS) production for both developed and developing countries, yet the technology has not fully utilised in the developing countries. Factors such as resources, accessibility, knowledge-gap and lack of experienced prosthetists remain the major causes of the lack of CAD/CAM system studies. Large-scale trials are required to employ digital fabrication in the developing regions, consequently advancing the production of high-quality CAD-CAM-derived TPS where most prosthetic and orthotics are needed.

Global prevalence of traumatic non-fatal limb amputation

BACKGROUND

Reliable information on both global need for prosthetic services and the current prosthetist workforce is limited. Global burden of disease estimates can provide valuable insight into amputation prevalence due to traumatic causes and global prosthetists needed to treat traumatic amputations.

OBJECTIVES

This study was conducted to quantify and interpret patterns in global distribution and prevalence of traumatic limb amputation by cause, region, and age within the context of prosthetic rehabilitation, prosthetist need, and prosthetist education.

STUDY DESIGN

A secondary database descriptive study.

METHODS

Amputation prevalence and prevalence rate per 100,000 due to trauma were estimated using the 2017 global burden of disease results. Global burden of disease estimation utilizes a Bayesian metaregression and best available data to estimate the prevalence of diseases and injuries, such as amputation.

RESULTS

In 2017, 57.7 million people were living with limb amputation due to traumatic causes worldwide. Leading traumatic causes of limb amputation were falls (36.2%), road injuries (15.7%), other transportation injuries (11.2%), and mechanical forces (10.4%). The highest number of prevalent traumatic amputations was in East Asia and South Asia followed by Western Europe, North Africa, and the Middle East, high-income North America and Eastern Europe. Based on these prevalence estimates, approximately 75,850 prosthetists are needed globally to treat people with traumatic amputations.

CONCLUSION

Amputation prevalence estimates and patterns can inform prosthetic service provision, education and planning.

Cost Analyses of Prosthetic Devices: A Systematic Review

OBJECTIVE

To synthesize extant literature on the cost-effectiveness of prosthetic interventions and explore applicability to low- and middle-income country (LMIC) settings.

DATA SOURCES

A systematic literature review using subject headings including "prosthetics," "amputation," and "cost analysis" was performed with PubMed, Embase, and Web of Science search engines, yielding 1194 articles. An additional 22 articles were identified via backward citation searching for 1144 total after duplicate removal. The search was last run in May of 2019.

STUDY SELECTION

Studies were included if they conducted an economic analysis of an upper or lower extremity prosthetic device. Studies were excluded if (1) full text was unavailable in English; (2) study was a systematic review or meta-analysis; or (3) study did not have a prosthetic comparison group. Using DistillerSR software, 2 authors independently conducted title and abstract screening. One author conducted full-text screening. The proportion of initially identified studies that met final inclusion criteria was 1% (12 of 1144).

DATA EXTRACTION

Data were dually extracted by 2 authors and reviewed by 3 additional authors.

DATA SYNTHESIS

All included studies (N=12) examined lower extremity amputations comparing advanced technology. No studies were conducted in LMICs. Comparable data between studies demonstrated (1) the cost-effectiveness of microprocessor- over nonmicroprocessor-controlled knees for transfemoral amputation in high-income settings; (2) equivocal findings regarding osseointegrated vs socket-suspended prostheses; and (3) increased cost for ICEX and modular socket systems over patellar tendon-bearing socket systems with no functional improvement.

CONCLUSIONS

There are few prosthetic cost analyses in the literature. Additional analyses are needed to determine the direct and indirect costs associated with prosthetic acquisition, fitting, and maintenance; the costs of amputee rehabilitation; and long-term economic and quality-of-life benefits. Such studies may guide future prosthetic and rehabilitative care, especially in resource-austere settings where prosthetic needs are greatest.

A novel, low-cost transradial socket fabrication method using mass-producible components and expanding rigid foam

BACKGROUND

Millions of people in low- and middle-income countries lack access to prosthetic care. A well-fitting, durable socket is important for prosthesis comfort and function, but conventional fabrication techniques require highly trained clinicians and specialized equipment.

OBJECTIVES

To increase access to prosthetic care by developing a simple, low-cost socket fabrication method that does not require specialized equipment or electricity, and can be performed by persons with minimal prosthetic training.

STUDY DESIGN

Socket fabrication methods and socket function were evaluated in a pilot feasibility study.

TECHNIQUE

We describe a rapid method for fabricating a rigid foam socket directly over the residual limb, with a mass producible, strong, cosmetically appealing plastic outer shell. We fabricated sockets for four individuals with unilateral transradial amputations and evaluated socket function.

RESULTS

An individual with no formal prosthetic training was able to fabricate sockets and assemble a functional, comfortable prosthesis system within 90 min. All necessary supplies can be provided in a kit for under US$100.

DISCUSSION

Further work is required to determine durability, assess comfort, refine suspension methods, and to develop instructional materials.

CONCLUSIONS

We developed a simplified, inexpensive method to fabricate sockets on the residual limb using expandable foam with an integrated cosmetic/structural covering (i.e. an exoskeletal system), for persons with transradial amputation. A transradial prosthesis socket can be fabricated in around 90 min. and all necessary materials, tools, and written instructions for fabrication and fitting can be provided in a kit. Specialized equipment and electricity are not required. Instructions for fabrication and fitting can be provided in multiple languages using online videos.

Improved Self-Reported Comfort, Stability, and Limb Temperature Regulation with an Immediate Fit, Adjustable Transtibial Prosthesis

Objective

The purpose of this investigation was to assess participants’ self-reported satisfaction with an adjustable, immediate fit transtibial prosthetic system as compared to their conventionally fabricated prosthetic device.

Design

A prospective study involving a 2-week single-group pre-post intervention design.

Setting

Physical medicine and rehabilitation clinic of a university hospital.

Participants

Adults (N=27) with transtibial limb loss.

Intervention

Participants were fit with the iFIT prosthetic system and instructed to wear it for a 2-week evaluation period.

Main Outcome Measure

A modified Prosthetic Evaluation Questionnaire (PEQ) scale was completed on the participant’s conventional prosthetic during the initial visit and the iFIT system after 2 weeks.

Results

Twenty-seven persons with lower limb loss were enrolled. Three were lost to follow-up leaving 24 participants with completed data. Three participants had recent amputations with no conventional device for comparison. The modified PEQ scores were significantly higher for the iFIT prosthetic in comparison to their conventional device (29.18±4.63 vs 23.82±6.38, P<.01). Participants were also found to perceive significantly better temperature control with the iFIT prosthetic system (4.19±0.68 vs 2.97±1.02, P<.001). Participants did not report any skin breakdown, prosthetic issues, or falls.

Conclusion

This immediate fit, adjustable transtibial prosthesis demonstrated significantly better patient satisfaction and temperature perception compared to conventional devices. These results are consistent with previous findings and further support the efficacy of an immediate fit adjustable transtibial prosthetic system. Longer-term studies in the United States and internationally are underway to assess the durability and efficacy of this new prosthesis in different populations and settings.

Limb Salvage for Musculoskeletal Tumors in the Austere Environment: Review of the Literature With Illustrative Cases Regarding Considerations and Pitfalls

Although there is literature discussing the treatment of acute and chronic trauma in austere environments, no literature or guidelines for the treatment of musculoskeletal tumors exist. This series discusses case examples with considerations and pitfalls of performing limb-salvage surgery in an underserved location.

Cases of limb-salvage surgery performed by the same orthopaedic oncologist in Haiti and the Dominican Republic are discussed with a review of the literature on limb salvage for musculoskeletal tumors in developing nations.

All patients successfully underwent limb-salvage surgery after considering multiple factors including tumor type and location. Patients with metastatic disease, likelihood of substantial blood loss, and poor health were not candidates for limb-salvage surgery.

Medical missions and the development of partnerships with established training programs make limb salvage a greater possibility. Knowledge of the facility, anesthesia support, and instrumentation available is vital. Advanced imaging, blood products, and allograft are likely unavailable or difficult to obtain. Established continuity of care is necessary, and training of the local surgeon should be provided. Surgery should only be considered if it is safe and provides more of a benefit to the patient than an amputation.

A systematic review on design technology and application of polycentric prosthetic knee in amputee rehabilitation

The objective of this paper is to conduct a systematic review on design technology and clinical application of polycentric prosthetic knee joint in the rehabilitation of trans-femoral amputees. Relevant studies were identified using electronic database such as PubMed, EMBASE, SCOPUS and the Cochrane Controlled Trials Register (Rehabilitation and Related Therapies) up to February 2020. Screening of abstracts and application of inclusion and exclusion criteria were made. Design, modeling, material use, kinematic study, simulation technique and clinical application of polycentric knee models used in many developed and developing countries have been reviewed. Out of 516 potentially relevant studies, 43 articles were included. Specific variables on technical and clinical aspects were extracted and added to summary tables. The results reveal that polycentric knees have a variety of geometries but the methods for comparing their performances are rare. The data of structural analysis using different simulation techniques are validated with experimental results for determining model accuracy. Gait analysis using the polycentric knee components provides a valid tool to correlate with experimental results. There are well-designed studies on the technological development of polycentric knees, however, high-quality clinical researches are scarce. Conventional clinical knowledge had considerable gaps concerning the effects of polycentric knee and their mechanical characteristics on human functioning with a lower-limb prosthesis. Still, further research is needed to develop and implement standardized measures on prosthetic knee joints for their effective use, function, durability, and cost-effectiveness.

Blast injuries in children: a mixed-methods narrative review

BACKGROUND AND SIGNIFICANCE

Blast injuries arising from high explosive weaponry is common in conflict areas. While blast injury characteristics are well recognised in the adults, there is a lack of consensus as to whether these characteristics translate to the paediatric population. Understanding blast injury patterns in this cohort is essential for providing appropriate provision of services and care for this vulnerable cohort.

METHODS

In this mixed-methods review, original papers were screened for data pertaining to paediatric injuries following blasts. Information on demographics, morbidity and mortality, and service requirements were evaluated. The papers were written and published in English from a range of international specialists in the field.

RESULTS

Children affected by blast injuries are predominantly male and their injuries arise from explosive remnants of war, particularly unexploded ordinance. Blasts show increased morbidity and mortality in younger children, while older children have injury patterns similar to adults. Head and burn injuries represent a significant cause of mortality in young children, while lower limb morbidity is reduced compared with adults. Children have a disproportionate requirement for both operative and non-operative service resources, and provisions for this burden are essential.

CONCLUSIONS

Certain characteristics of paediatric injuries arising from blasts are distinct from that of the adult cohort, while the intensive demands on services highlight the importance of understanding the diverse injury patterns in order to optimise future service provisions in caring for this child blast survivor.

Rehabilitation evaluation of the newly developed polymeric based passive polycentric knee joint

Objective: The lower limb amputation is one of the major concerns for the amputee's daily life and the trans-femoral (TF) amputation is being paid a lot of attention because of its functional requirement in flexion-extension motion. Though significant progress has been made for the development of high end prosthetic knee joint, the affordability of the same is still a great concern. Thus, a passive polycentric knee joint was developed and the health related quality of life (HRQL) before and after the fixation of the prosthesis, and performance of the same were studied.Design: After 6 months of fixation, the HRQL and performance of the prosthetic device were evaluated.Results: The HRQL after the fixation was found to be increased, where the improvement on the physical and mental score was found to be 49 and 46%, respectively, in comparison with pre-fixation stage. The global score (G) for the prosthetic function was found to be 63, which confirmed the increased performance of the prosthesis.Conclusions: The improved HRQL and G of prosthetic performance confirmed the enhanced performance of the prosthesis. It is concluded that the developed passive polycentric knee joint could be explored in large scale for the TF amputees.Implications for rehabilitationThe above knee (AK) amputation is a surgical interference that severs the thigh segment between the knee and hip joints.The above knee prosthesis consists of a socket, knee joint, pylon and foot.The artificial prosthetic knee joint imitates the functions of human knee to achieve the flexion-extension motion of the above knee amputee.The satisfaction of the amputees with the usage of the existing artificial prosthetic knee joint is still a concern. Hence, a passive prosthetic knee joint was developed and its effect on the quality of life of trans-femoral amputee was evaluated using health related quality of life (HRQL) before and after the fixation of the prosthesisThe HRQL after the fixation was found to be increased in comparison with pre-fixation stage.The global score for the prosthetic function was also found to be increased which confirmed the increased performance of the prosthesis.It is anticipated that the developed knee joint is expected to make huge impact due to its function, performance and affordability.

Remote fitting procedures for upper limb 3d printed prostheses

BACKGROUND

The objective of the current investigation was twofold: i) describe a remote fitting procedure for upper limb 3D printed prostheses and ii) assess patient satisfaction and comfort with 3D printed prostheses fitted remotely.

METHODS

A qualitative study using content and score analysis to describe patient satisfaction after remote prosthetic fitting. Research participants reported QUEST and OPUS scores that allow for perceived rating of general aspects and functionality of upper limb prostheses.

RESULTS

Six children (three girls & boys, 6-16 years of age) and 2 adult males (25 and 59 years of age) with congenital (n = 7) and acquired (n = 1) upper limb loss participated in this study. Highest device satisfaction items of the QUEST include weight (4.50 ± 0.76), safety (4.38 ± 0.52), and ease of use (4.13 ± 0.64). Functional tasks of the OPUS observe that prosthesis donning and doffing (1.5 ± 0.84) and drinking from a paper cup (1.75 ± 0.89) were the easiest functional tasks.

CONCLUSION

The presented methodology for remote fitting of 3D printed upper-limb prostheses exhibits significant potential for rapid fabrication of functional prostheses to developing countries due to increased availability of digital devices in rural areas.

An Affordable Insole-Sensor-Based Trans-Femoral Prosthesis for Normal Gait

This paper proposes a novel and an affordable lower limb prosthesis to enable normal gait kinematics for trans-femoral amputees. The paper details the design of a passive prosthesis with magneto-rheological (MR) damping system and electronic control. A new control approach based on plantar insole feedback was employed here. Strategically placed sensors on the plantar insole provide required information about gait cycle to a finite state controller for suitable action. A proportional integral (PI) based current controller controls the required current for necessary damping during gait. The prosthesis was designed and developed locally in India keeping in view the cost, functionality, socio-economic, and aesthetic requirements. The prototype was experimentally tested on a trans-femoral amputee and the results are presented in this work. The implementation of the proposed design and control scheme in the prototype successfully realizes the notion that normal gait kinematics can be achieved at a low cost comparable to passive prostheses. The incurring cost and power expenditure of the proposed prosthesis are evaluated against passive and active prostheses, respectively. The commercial implications for the prosthesis were explored on the basis of recommendations of ISPO Consensus Conference on Appropriate Prosthetic Technology in Developing Countries. The key objective of this work is to enable lucid design for development of an affordable prosthesis in a low-resource setting.

A Low-Cost, Open-Source, Compliant Hand for Enabling Sensorimotor Control for People with Transradial Amputations

In this paper, we describe the design and implementation of a low-cost, open-source prosthetic hand that enables both motor control and sensory feedback for people with transradial amputations. We integrate electromyographic pattern recognition for motor control along with contact reflexes and sensory substitution to provide feedback to the user. Compliant joints allow for robustness to impacts. The entire hand can be built for around $550. This low cost makes research and development of sensorimotor prosthetic hands more accessible to researchers worldwide, while also being affordable for people with amputations in developing nations. We evaluate the sensorimotor capabilites of our hand with a subject with a transradial amputation. We show that using contact reflexes and sensory substitution, when compared to standard myoelectric prostheses that lack these features, improves grasping of delicate objects like an eggshell and a cup of water both with and without visual feedback. Our hand is easily integrated into standard sockets, facilitating long-term testing of sensorimotor capabilities.

Improved design and development of a functional moulded prosthetic foot

PURPOSE

In the Indian scenario, the Jaipur foot is a low-cost breakthrough that enabled the disabled person to adapt to the Indian environment. The aim of this study is to modify the present foot in terms of ankle support design and method of fabrication, foot moulds profile and the inner core material in order to improve the performance and durability.

METHOD

The optimized design of ankle support and flat foot profile moulds suitable for both left and right foot were developed through CAD/CAM and prosthetic feet were fabricated using ethylene vinyl acetate (EVA) foam as an appropriate alternative core material for microcellular rubber (MCR). The developed prosthetic feet were tested for rigidity by load-deflection analysis in universal testing machine.

RESULT

EVA foot had shown better rigidity than conventional MCR foot, which will help in weight transfer during walking and increase the durability. The CAD modeled ankle support and single block EVA had made the manufacturing process easy and reduced the weight of foot and improved Gait to the person fitted with it due to improved flat foot profile.

CONCLUSION

The new artificial foot had proven to be efficacious technically as well as functionally, which is clearly borne out from the extremely positive feedback given by the amputees. Implications of Rehabilitation Persons with below knee amputation are usually provided with transtibial prosthesis, which allows for easier ambulation and helps them to get back to their normal life. Transtibial prosthesis is an artificial limb that replaces a lower limb that is amputated below the knee. In our study, a new prosthetic foot with a modified ankle support and flat foot profile using better inner-core material than the conventional Jaipur foot was developed and the process was also optimized for mass production. The developed prosthetic foot can be fitted with both above and below knee exoskeleton type of prosthesis.

Biomechanical design considerations for transradial prosthetic interface: A review

Traditional function and comfort assessment of transradial prostheses pay scant attention to prosthetic interface. With better understanding of the biomechanics of prosthetic interface comes better efficiency and safety for interface design; in this way, amputees are more likely to accept prosthetic usage. This review attempts to provide design and selection criteria of transradial interface for prosthetists and clinicians. Various transradial socket types in the literature were chronologically reviewed. Biomechanical discussion of transradial prosthetic interface design from an engineering point of view was also done. Suspension control, range of motion, stability, as well as comfort and safety of socket designs have been considered in varying degrees in the literature. The human-machine interface design should change from traditional "socket design" to new "interface design." From anatomy and physiology to biomechanics of the transradial residual limb, the force and motion transfer, together with comfort and safety, are the two main aspects in prosthetic interface design. Load distribution and transmission should mainly rely on achieving additional skeletal control through targeted soft tissue relief. Biomechanics of the residual limb soft tissues should be studied to find the relationship between mechanical properties and the comfort and safety of soft tissues.

Priorities in lower limb prosthetic service delivery based on an international survey of prosthetists in low- and high-income countries

BACKGROUND

Prosthetic services, including the provision of an appropriate prosthesis, are a crucial part of the rehabilitation process for individuals with lower limb amputations. However, globally there exist unique challenges in the delivery of prosthetic services that are limiting rehabilitation outcomes and consequently the well-being and socio-economic status of individuals with lower limb amputations.

OBJECTIVES

The objective of this work was to explore the issues related to the provision of appropriate prosthetic technologies and to compare these across different economies of the world.

STUDY DESIGN

Cross-sectional survey.

METHODS

An online survey was developed and distributed to prosthetic practitioners providing services in countries around the world. An open-coding thematic content analysis procedure was applied to extract key themes from the data.

RESULTS

The response codes defined three overall themes of lower limb prosthetic delivery, and several key differences between higher and lower income countries emerged. Namely, a higher emphasis on part/material availability, practitioner training and durability in lower income countries was found. High costs were an issue raised by practitioners in all countries.

CONCLUSION

Practitioners around the world share many of the same concerns; however, some lower income countries face important and pressing issues that limit their ability to provide adequate prosthetic services.

CLINICAL RELEVANCE

This work highlights the most crucial service and technology-related needs, as perceived by trained prosthetic practitioners, of populations requiring lower limb prosthetic treatment around the world. Additionally, the results may be used to prioritize prosthetic-related health-care initiatives led by other researchers, governments and organizations working to improve services internationally.

Redistributing prostheses – from Britain to Sri Lanka

How used British mobility devices are being turned into brand new limbs for Sri Lankans.

Provision of prosthetic and orthotic services in low-income countries: a review of the literature

BACKGROUND

Disability is inextricably linked to poverty. A total of 80% of the disabled population lives in low-income countries. The demand for prosthetic and orthotic services in these countries is increasing, and a variety of methods to provide services are currently used.

OBJECTIVES

To assess current models of provision to facilitate sustainable, evidence-based prosthetic and orthotic services.

STUDY DESIGN

Literature review.

METHODS

A literature search was performed through Medline (Ovid), PubMed, ISI Web of Knowledge, EMBASE and RECAL Legacy using combinations of subject heading and text word searching strategies. Full-text publications were critically appraised and ranked according to the Scottish Intercollegiate Guidelines Network guidelines.

RESULTS

Three areas were deemed pertinent to the research question. Studies were grouped into one or more of these categories based on the issues addressed: instigators, types of service provision, demographics and region-specific issues. It was found that many complex factors influence prosthetic and orthotic services in low-income countries. Demographic and regional idiosyncrasies require prosthetic and orthotic services to be tailored to address the specific needs of individual countries.

CONCLUSIONS

The lack of and quality of available research made efficacy of methods used to provide services in low-income countries difficult to determine.

Kinematics of lower limbs of healthy Chinese people sitting cross-legged

BACKGROUND

Sitting cross-legged as an activity of daily living and its kinematics have significantly different demands on the arthroplasty of hip and knee, which can be referred in the design of joint arthroplasty.

OBJECTIVES

The purpose of this study was to obtain the kinematics of the lower limb in Chinese people during cross-legged sitting.

STUDY DESIGN

This study identified the necessary requirements for joint arthroplasty to carry out sitting cross-legged activity.

METHODS

A total of 40 healthy Chinese participants (average age = 23.8 years) performed six cross-legged sitting trials per person. Three-dimensional kinematic data of ankle, knee, and hip joints were collected; the means of the three-dimensional angles of these three joints were calculated.

RESULTS

At the hip, the range of motion of the flexion was 101.7°, the abduction reached 43.2°, and the range of motion of the external rotation was 36.4°. At the knee, the range of motion of the flexion was 131.9° and the range of motion of the internal rotation reached 32.4°. At the ankle, the range of motion in three planes was not great.

CONCLUSIONS

Such motion ranges were likely to result in prosthetic dislocation. The results would provide valuable references for prosthesis design in the Chinese population.

Design and assessment of a low-cost, electromyographically controlled, prosthetic hand

The study reported here explored the design and realization of a low-cost, electromyographically controlled hand prosthesis for amputees living in developing countries. The developed prosthesis is composed of a light aluminum structure with opposing fingers connected to a DC motor that imparts only the movement of grasp. Problems associated with surface electromyographic signal acquisition and processing, motor control, and evaluation of grasp force were addressed, with the goal of minimizing cost and ensuring easy assembly. Simple analog front ends amplify and condition the electromyographic signals registered from two antagonist muscles by surface electrodes. Analog signals are sampled at 1 kHz and processed by a microcontroller that drives the motor with a supply voltage proportional to the muscular contraction, performing the opening and closing of the opposing fingers. Reliable measurements of the level of muscle contractions were obtained by specific digital processing: real-time operators implementing the root mean square value, mean absolute value, standard deviation, and mean absolute differential value were compared in terms of efficiency to estimate the EMG envelope, computational load, and time delay. The mean absolute value operator was adopted at a time window of 64 milliseconds. A suitable calibration procedure was proposed to overcome problems associated with the wide variation of electromyograph amplitude and background noise depending on the specific patient’s muscles selected. A pulse-width modulated signal drives the DC motor, allowing closing and opening of the prosthesis. The relationship between the motor-driver signal and the actual hand-grasp force developed by the prosthesis was measured using a hand-held grip dynamometer. The resulting force was proportional to current for moderate values of current and then saturated. The motor torque, and, in turn, the force elicited, can be measured by sensing the current absorbed by the motor. Therefore, the grasp force can be opportunely limited or controlled. The cost of the only electronic and mechanical components of the electromyographically controlled hand was about US$50; other costs, such as the cost of labor to assemble the prosthesis and the production of adapters for patients, were not estimated.

Designing for scale: development of the ReMotion Knee for global emerging markets

Amputees living in developing countries have a profound need for affordable and reliable lower limb prosthetic devices. The World Health Organization estimates there are approximately 30 million amputees living in low-income countries, with up to 95% lacking access to prosthetic devices. Effective prosthetics can significantly affect the lives of these amputees by increasing opportunity for employment and providing improvements to long-term health and well-being. However, current solutions are inadequate: state-of-the-art solutions from the US and Europe are cost-prohibitive, while low-cost devices have been challenged by poor quality and/or unreliable performance, and have yet to achieve large scale impact. The introduction of new devices is hampered by the lack of a cohesive prosthetics industry in low-income areas; the current network of low-cost prosthetic clinics is informal and loosely organized with significant disparities in geography, patient volume and demographics, device procurement, clinical and logistical infrastructure, and funding. At D-Rev (Design Revolution) we are creating the ReMotion Knee, which is an affordable polycentric prosthetic knee joint that performs on par with devices in more industrialized regions, like the US and Europe. As of September 2012, over 4200 amputees have been fitted with the initial version of the ReMotion Knee through a partnership with the JaipurFoot Organization, with an 79% compliance rate after 2 years. We are currently scaling production of the ReMotion Knee using centralized manufacturing and distribution to serve the existing clinics in low-income countries and increase the availability of devices for amputees without access to appropriate care. At D-Rev, we develop products that target these customers through economically-sustainable models and provide a measurable impact in the lives of the world's amputees.

Improving the gait performance of non-fluid-based swing-phase control mechanisms in transfemoral prostheses

A prosthetic swing-phase control mechanism simulates the action of leg musculature, aiding gait function by controlling the duration of swing, extent of heel-rise, and by allowing the shank to smoothly decelerate into full knee extension without excessive impact. Non-fluid-based mechanisms have the potential to provide a durable and affordable solution as required in many parts of the world, but the design variables that lead to improved performance of non-fluid-based swing-phase control technologies are not well established. Seven transfemoral amputees were fitted with a prosthetic knee joint and different non-fluid-based swing-phase setups were systematically assessed. Clinical testing included walk tests utilizing a potentiometer (to measure knee flexion angles) and accelerometer (to measure terminal impact decelerations) mounted on the prosthetic limb. As hypothesized, the friction and spring systems improved gait function. This includes an increased walking speed that closely matched high-end hydraulic prosthetic knee joints, decreased and more normal maximum prosthetic knee flexion, decreased flexion duration, and lower terminal impact. Further improvements were obtained using a dual spring system, two springs in series, over the more conventional single spring system. Non-fluid-based swing-phase control mechanisms are simple and significantly improve the performance of prostheses. Their application is ideal where size, weight and cost may be constrained.

Assistive technology in developing countries: a review from the perspective of the Convention on the Rights of Persons with Disabilities

BACKGROUND

The 'Convention on the Rights of Persons with Disabilities' (CRPD) requires governments to meet the assistive technology needs of citizens. However, the access to assistive technology in developing countries is severely limited, which is aggravated by a lack of related services.

OBJECTIVES

To summarize current knowledge on assistive technology for low- and lower-middle-income countries published in 1995 or later, and to provide recommendations that facilitate implementation of the CRPD.

STUDY DESIGN

Literature review.

METHODS

Literature was searched in web-based databases and reference lists. Studies carried out in low- and lower-middle-income countries, or addressing assistive technology for such countries, were included.

RESULTS

The 52 included articles are dominated by product oriented research on leg prostheses and manual wheelchairs. Less has been published on hearing aids and virtually nothing on the broad range of other types of assistive technology.

CONCLUSIONS

To support effective implementation of the CRPD in these countries, there is a need for actions and research related particularly to policies, service delivery, outcomes and international cooperation, but also to product development and production.

CLINICAL RELEVANCE

The article has a potential to contribute to CRPD compliant developments in the provision of assistive technology in developing countries by providing practitioners with an overview of published knowledge and researchers with identified research needs.

Lower-limb prosthetic technologies in the developing world: A review of literature from 1994-2010

In the mid-1990s, a number of key publications and meetings of experts identified major technical issues associated with prosthetic technologies intended for developing countries. These included inadequate durability of prosthetic feet, poor socket quality and prosthetic fit, improper alignment of prostheses, and inferior function of components. To examine the progress that has been made since then in addressing these issues, a comprehensive review of literature was performed. In total, 106 articles were selected and included in the review. The review examined prosthetic technologies categorized into feet and ankles, knees, sockets and suspension, and materials, structures, and alignment methods. Moreover, publications were categorized as technical development, clinical (lab-based) testing, or clinical field testing studies. The results reveal important work that has been carried out to develop and implement standardized outcome measures during field testing, allowing various existing prosthetic technologies to be evaluated in terms of their use, function, durability, and other factors. Progress has also been made toward addressing the aforementioned limitations of prosthetic technologies, however, more research and development is required. This includes improving the durability of the external cosmetic features of prosthetic feet, developing more functional prosthetic knee joints, and simplifying fabrication techniques to further improve outcomes associated with socket fit and prosthetic alignment. Research and development collaborations between developed and developing countries, and the dissemination of ongoing research, development, and evaluation activities are essential to the advancement of prosthetic technologies in these regions.

Mechanical testing of prosthetic feet utilized in low-income countries according to ISO-10328 standard

This report summarizes the results from 1132 ISO-10328 standard tests performed on 21 different prosthetic foot models commonly utilized in the developing world. None of the tested feet passed the strictest ISO testing protocol. All but one failed at the initial Static Proof test, which simulates a single momentary overload, due to permanent forefoot deformation. In addition, all tested feet had significant internal failures that were visible when sectioned longitudinally. Static Proof testing revealed average permanent deformation of the forefoot of all feet that exceeded the optional 5 mm ISO requirement. Forefoot deformation for non-Jaipur rubber feet came closest to meeting the standard at 8.3+/-3.4 mm; deformation of the various types of rubber Jaipur feet was the greatest at 22.5+/-5.4 mm. Forefoot deformation for polyurethane (PU) feet was 13.6+/-5.5 mm. Forefoot deformation of the ethyl-vinyl-acetate (EVA) feet was slightly greater than the Jaipur feet at 22.8+/-5.7 mm. After the Static Strength test, which simulates a higher momentary overload, permanent deformation of the feet increased. The average maximum deformation for rubber SACH forefeet varied from 17 - 30 mm, and 11 - 26 mm for the heel; Jaipur forefeet 47 - 60 mm and heels 13 - 19 mm; PU forefeet 20 - 44 mm and heels 20 - 33 mm; and EVA forefeet 33 - 50 mm and heels 16 - 31 mm. After completion of the Cyclic Test the prosthetic feet were sawn in half and closely examined visually. All feet revealed internal derangements: (i) Deformation of rubber or PU foam under the keel of forefoot and/or heel: HCMC, VI, EB1, BAVI, HI Cambodia, Myanmar, Angola, TATCOT, Kingsley and CR; (ii) Delamination from the keel: Mozambique, PHN, and Pro-cirugia; and (iii) Delamination between foam layers: BMVSS, NISHA, MUKTI, and OM. The influence of the two environmental factors tested was minimal for rubber feet with respect to deformation and inconsistent for the polymer feet; in particular for the forefeet. Creep increased with humidity exposure in some feet of natural rubber. However, creep decreased with ultraviolet (UV) exposure for these natural rubber feet, as was also the case for EVA feet, whereas the creep increased for two PU feet. Comparison of the effect of humidity and UV exposure generally showed less creep with UV exposure. In conclusion, ISO-10328 testing prior to release of a new foot construction for amputee use appears to be useful in the developing countries as well as in the developed world, even though it does not simulate the wear on the plantar surface that is seen clinically in barefoot walking. Inspection of the internal structures after the laboratory testing has been shown to reveal occult failure mechanisms in all tested feet.

Clinical field testing of vulcanized rubber feet for trans-tibial amputees in tropical low-income countries

In a prospective, controlled study, 186 prosthetic rubber feet of different designs were fitted to amputees with trans-tibial prostheses. There were 158 amputees available for follow-up. The amputee compliance was good and 89% were satisfied with their device. After 18 months of use one VI-Solid rubber foot from VVAF in Cambodia had failed, as compared to 11% failures with the same foot with a heel cavity, 3% with the EB-1 sandwich construction from POF in Vietnam, all performing significantly better than the 62% encountered with the vulcanized rubber foot from ICRC in Cambodia; the latter representing half of the feet failing in amputees walking bare-footed. Nearly all failures were located at the foot-sole or the keel. The failure rate was 20% for the HI-Cambodia foot after 12 months. After 24 months of use, still only one VI-Solid rubber foot had failed and this foot design was found superior to the others in regard of durability.

Clinical field follow-up of high density polyethylene (HDPE)-Jaipur prosthetic technology for trans-tibial amputees

The purpose of this study was to examine the outcome of the application of the High Density Polyethylene (HDPE)-Jaipur prosthetic construction in fitting trans-tibial amputees in a number of projects in the developing world. Projects in Honduras, Uganda and India were visited. Three hundred and twenty (320) patients had been provided with a HDPE-Jaipur prosthesis and of these 172 were seen for a technical and clinical follow-up after a median of 35 months. More than half the amputations were due to trauma, the remainder to disease. Fabrication and fitting in the three projects was carried out by individuals who had undertaken a twice week training course provided by Bhagwan Mahaveer Viklang Sahayata Samiti limb centre in Jaipur. The individuals involved had limited background training in prosthetics. Craftsmanship and fit were assessed as being poor in 56% of cases. The technical quality of the Jaipur foot was considered acceptable as its performance was better than previously observed results. Although there was patient satisfaction of 85% and compliance of 94% the HDPE-Jaipur trans-tibial system was not considered acceptable as 49% reported walking distances less than 1km and 36% discomfort. The major inadequacy in outcome relates to the use for fabrication and fitting of individuals with inadequate education and training.

Clinical field testing of trans-femoral prosthetic technologies: resin-wood and ICRC-polypropylene

The aim of this study was to evaluate the use of 2 different trans-femoral prosthetic systems, a conventional wood-resin design and an ICRC polypropylene design, in a developing country when implemented by teachers and their associates at an ISPO Caegory II recognised training establishment. The study was conducted at the Tanzanian Training Centre for Orthopaedic Technologists (TATCOT). Amputees were selected from a cohort of younger amputees, mostly with traumatic amputations, 27 were provided with the conventional design of prosthesis and 35 with the ICRC design. The outcome was evaluated clinically and technically after a median of 20 months (conventional) and 15 months (ICRC) respectively. For all prostheses provided the craftsmanship was considered acceptable in 71%, and patient satisfaction was assessed as 92%, patient compliance as 98%. Failures requiring a major intervention represented 32%. Both systems provided in this controlled environment were considered to give an acceptable clinical and technical result.

Characterisation of prosthetic feet used in low-income countries

Eleven kinds of prosthetic feet that were designed for use in low-income countries were mechanically characterised in this study. Masses of the different kinds of prosthetic feet varied substantially. Dynamic properties, including damping ratios and resonant frequencies, were obtained from step unloading tests of the feet while interacting with masses comparable to the human body. Data showed that for walking, the feet can be appropriately modeled using their quasistatic properties since natural frequencies were high compared to walking frequencies and since damping ratios were small. Roll-over shapes, the effective rocker (cam) geometries that the feet deform to under walking loads, were determined using a quasistatic loading technique and a spatial transformation of the ground reaction force's centre of pressure. The roll-over shapes for most of the prosthetic feet studied were similar to the roll-over shape of the SACH (solid-ankle cushioned heel) prosthetic foot. All roll-over shapes showed a lack of forefoot support, which may cause a "drop-off" experience at the end of single limb stance and shorter step lengths of the contralateral limb. The roll-over shapes of prosthetic feet appear useful in characterization of foot function.

A picture of amputees and the prosthetic situation in Haiti

PURPOSE

The purpose of this study is to present the situation of Haitian amputees and to outline some of the major barriers in Haiti that prevent people from receiving prosthetic treatment.

METHOD

Interviews were conducted with amputees throughout Haiti using a 42-question questionnaire. Additionally, interviews were conducted with traditional healers, health care workers, and leaders of handicap associations. Each interview was manuscripted and the data were subsequently coded and analysed in the USA.

RESULTS

There are three full-time prosthetic shops and two part-time prosthetic shops in Haiti, all of which are severely limited in the scope of services they are able to provide amputees due to insufficient supplies and inadequately trained personnel. Only 25% of the 164 amputees interviewed had ever had a prosthetic limb. Typically prosthetic treatment is inaccessible and unaffordable for amputees, which prevents many from seeking treatment. The most common cause of amputation in Haiti is infection, followed by motor vehicle accidents.

CONCLUSION

There must be additional cooperation between Haitian patients, doctors, traditional healers, prosthetists, and government officials in order to provide more adequate prosthetic care. Prosthetic treatment in Haiti can be successful with cooperation of different entities, proper rehabilitation therapy, adequately trained personnel, and development of culturally appropriate limbs.

Preliminary experiences with modified SACH feet manufactured and used in a tropical developing world setting

In a prospective study of polypropylene (PP) prostheses for trans-tibial amputees four different modified SACH feet were used. These are identified as: 1. BAVI from the national manufacturer of componentry in BaVi; 2. HCMC a design initiated by the International Committee of the Red Cross (ICRC) together with the Army Factory in Ho Chi Minh City; 3. HI from Handicap International; 4. VI from Veterans International, Cambodia. Four (4) from 5 BAVI feet, 7 from 9 HCMC feet and 4 from 10 HI feet failed after about a year on average, whereas none of 10 VI feet had failed after 19 months. Dimensional differences in the ankle part and in the height of the foot in the different designs made interchangeability impossible.

Evaluation of use and durability of polypropylene trans-tibial prostheses

Forty-three (43) trans-tibial prostheses with a mean period of use of 33 months were evaluated in terms of utilisation and durability. The majority of the prostheses (80%) were worn by amputees with demanding occupations, such as farmers, fishermen and tradesmen. The prostheses were in use approximately 9 hours per day. No major or frequent breakdowns of the polypropylene prosthetic components were found. The suspension belts were the parts most frequently affected; a total of 32 needed replacement after an average 11 months of use. Eleven (11) prostheses were completely replaced, more than half at least partly because of socket-fitting problems. In all, socket-fitting problems were found in 15 prostheses, causing pain and consequently limitation of use. While the prosthetic polypropylene components were satisfactory, the rubber foot was a major cause of early breakdown. A total of 40 feet were replaced; their mean period of use before breakdown was 9 months. In practice, parts were frequently replaced at a later stage than desirable, meaning that there was frequent "overuse" of prostheses with worn parts. Measures were taken to increase the life span of the prosthesis: change in the design of the foot; issuing a spare foot with the prosthesis; strengthening the suspension belt. Additional evaluations are necessary to confirm the degree to which the findings are representative.

A closer look at amputees in Vietnam: a field survey of Vietnamese using prostheses

This study aims to improve the quality and effectiveness of follow-up data on prosthetics in developing countries. In order to bridge the gap between members of non-governmental organizations and their international patients, a field survey was conducted via direct interviews in Vietnam. Eighty-three (83) patients in 5 different geographic regions were interviewed using a standardized assessment tool designed by the author. Demographic information, questions of prosthetic history, inquiries into function, lifestyle and occupation, and queries of social and family integration were asked of each patient. While the overall results prove salutary for those who serve the amputees of developing countries, it is clear that amputation presents a substantial challenge to the Vietnamese patient. On one hand, respondents wore their prostheses over 12 hours each day on average, rated their prostheses as quite comfortable, and were altogether satisfied with their prosthetic treatment. In addition, the provision of care for Vietnamese with amputations has improved markedly over the past few decades. On the other hand, many patients related the barriers they encountered due to their amputation, including their departure from previous careers, inability to perform rigorous physical activities, and difficulties with social interactions. Furthermore, discrepancies in care were noted between demographic groups and amongst different regions. The questionnaire developed for this study may provide a useful evaluative tool for agencies working throughout the developing world. The use of such a standardized questionnaire could greatly improve the evaluation and comparison of prosthetic programmes and help guide the efforts of such organizations in developing countries.