Prosthetic options available for the diabetic lower limb amputee

Design trends in actuated lower-limb prosthetic systems: a narrative review

INTRODUCTION

Actuated lower limb prostheses, including powered (active) and semi-active (quasi-passive) joints, are endowed with controllable power and/or impedance, which can be advantageous to limb impairment individuals by improving locomotion mechanics and reducing the overall metabolic cost of ambulation. However, an increasing number of commercial and research-focused options have made navigating this field a daunting task for users, researchers, clinicians, and professionals.

AREAS COVERED

The present paper provides an overview of the latest trends and developments in the field of actuated lower-limb prostheses and corresponding technologies. Following a gentle summary of essential gait features, we introduce and compare various actuated prosthetic solutions in academia and the market designed to provide assistance at different levels of impairments. Correspondingly, we offer insights into the latest developments of sockets and suspension systems, before finally discussing the established and emerging trends in surgical approaches aimed at improving prosthetic experience through enhanced physical and neural interfaces.

EXPERT OPINION

The ongoing challenges and future research opportunities in the field are summarized for exploring potential avenues for development of next generation of actuated lower limb prostheses. In our opinions, a closer multidisciplinary integration can be found in the field of actuated lower-limb prostheses in the future.

Characterizing the Gait of People With Different Types of Amputation and Prosthetic Components Through Multimodal Measurements: A Methodological Perspective

Prosthetic gait implies the use of compensatory motor strategies, including alterations in gait biomechanics and adaptations in the neural control mechanisms adopted by the central nervous system. Despite the constant technological advancements in prostheses design that led to a reduction in compensatory movements and an increased acceptance by the users, a deep comprehension of the numerous factors that influence prosthetic gait is still needed. The quantitative prosthetic gait analysis is an essential step in the development of new and ergonomic devices and to optimize the rehabilitation therapies. Nevertheless, the assessment of prosthetic gait is still carried out by a heterogeneous variety of methodologies, and this limits the comparison of results from different studies, complicating the definition of shared and well-accepted guidelines among clinicians, therapists, physicians, and engineers. This perspective article starts from the results of a project funded by the Italian Worker's Compensation Authority (INAIL) that led to the generation of an extended dataset of measurements involving kinematic, kinetic, and electrophysiological recordings in subjects with different types of amputation and prosthetic components. By encompassing different studies published along the project activities, we discuss the specific information that can be extracted by different kinds of measurements, and we here provide a methodological perspective related to multimodal prosthetic gait assessment, highlighting how, for designing improved prostheses and more effective therapies for patients, it is of critical importance to analyze movement neural control and its mechanical actuation as a whole, without limiting the focus to one specific aspect.

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

15 studies were included. Participants (n = 144) were predominantly male (88.2%), had unilateral amputation (95.8%) from non-dysvascular causes (87.5%), and were classified as unlimited community ambulators or active adults (56.9%). 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, but only under select conditions. This article is protected by copyright. All rights reserved.

Sex difference for the risk of amputation in diabetic patients: A systematic review and meta-analysis

The risk of amputation is a sequelae of diabetic foot ulceration, which are significantly increased in diabetic patients and caused huge morbidly and mortality. However, whether the risk amputation in diabetic patients are differing in male and female remains inconclusive. We therefore conducted a systematic review and meta-analysis to assess the sex difference for the risk of amputation in diabetic patients. We systematically searched PubMed, EmBase, and the Cochrane library to identify eligible study from their inception up to November 2020. The diagnostic value of male patients on subsequent amputation risk were assessed by using sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR), diagnostic odds ratio (DOR), and area under the receiver operating characteristic curve (AUC). Twenty-two studies recruited a total of 33,686,171 diabetic patients were selected for quantitative analysis. The risk of amputation in male diabetic patients was greater than female diabetic patients (DOR: 1.38; 95%CI: 1.13–1.70; P<0.001). The sensitivity and specificity for male diabetic patients on the risk of amputation were 0.72 (95%CI: 0.72–0.73), and 0.51 (95%CI: 0.51–0.51), respectively. Moreover, the PLR and NLR of male diabetic patients for predicting amputation were 1.13 (95%CI: 1.05–1.22), and 0.82 (0.72–0.94), respectively. Furthermore, the AUC for male diabetic patients on amputation risk was 0.56 (95%CI: 0.48–0.63). This study found male diabetic patients was associated with an increased risk of amputation than female diabetic patients, and the predictive value of sex difference on amputation risk in diabetic patients was mild.

Synthesis and characterization of a silver nanoparticle-containing polymer composite with antimicrobial abilities for application in prosthetic and orthotic devices

Background

The presence of skin problems in patients using external lower limb prosthesis is recurrent. This has generated the need to develop interfaces for prosthesis with the ability to control microbial growth. Silver nanoparticles (AgNPs) have been implemented in the development of biomaterials because of their high antimicrobial activity. This article discusses the development of an AgNP-containing polymer composite with antimicrobial activity for developing prosthetic liners.

Methods

AgNPs were synthesized using a photochemical method and certain physicochemical properties were characterized. Furthermore, the antimicrobial activity of AgNPs against Staphylococcus aureus ATCC 25923 and methicillin-resistant Staphylococcus aureus (MRSA), was assessed on the basis of their minimum inhibitory concentrations (MICs). AgNPs were incorporated into a silicon elastomer to assess certain physicomechanical properties, antimicrobial activity and cytotoxic effect of the material.

Results

The maximum antimicrobial activity of the material against Staphylococcus aureus ATCC 25923 and MRSA was 41.58% ±2.97% at AgNP concentration of 32.98 μg/mL and 14.85% ±5.94% at AgNP concentration of 16.49 μg/mL, respectively. Additionally, the material exhibited tensile yield strength, rupture tensile strength, and tensile modulus of elasticity of 0.70 - 1.10 MPa, 0.71–1.06 MPa, and 0.20 - 0.30 MPa, respectively. The mechanical characteristics of the material were within the acceptable range for use in external lower limb prosthetic and orthotic interfaces.

Conclusions

It was possible to incorporate the AgNPs in a silicone elastomer, finding that the composite developed presented antimicrobial activity against Staphylococcus aureus ATCC 25923 and MRSA when compared to non-AgNP material samples.

Common and specific gait patterns in people with varying anatomical levels of lower limb amputation and different prosthetic components

The present study's aim was to identify the kinematic and kinetic gait patterns and to measure the energy consumption in people with amputation according to both the anatomical level of amputation and the type of prosthetic components in comparison with a control group matched for the gait speed. Fifteen subjects with unilateral transtibial amputation (TTA), forty with unilateral transfemoral amputation (TFA) (9 with mechanical, 17 with CLeg and 14 with Genium prosthesis) and forty healthy subjects were recruited. We computed the time-distance gait parameters; the range of angular motion (RoM) at hip, knee and ankle joints, and at the trunk and pelvis; the values of the 2 peaks of vertical force curve; the full width at half maximum (FWHM) and center of activity (CoA) of vertical force; the mechanical behavior in terms of energy recovery (R-step) and energy consumption. The main results were: i) both TTA and TFA show a common gait pattern characterized by a symmetric increase of step length, step width, double support duration, pelvic obliquity, trunk lateral bending and trunk rotation RoMs compared to control groups. They show also an asymmetric increase of stance duration and of Peak1 in non-amputated side and a decrease of ankle RoM in amputated side; ii) only TFA show a specific gait pattern, depending on the level of amputation, characterized by a symmetric reduction of R-step and an asymmetric decrease of stance duration, CoA and FWHM and an increase of Peak1 in the amputated side and of hip and knee RoM, CoA and FWHM in the non-amputated side; iii) people with amputation with Genium prosthesis show a longer step length and increased hip and knee RoMs compared to people with amputation with mechanical prosthesis who conversely show an increased pelvic obliquity: these are specific gait patterns depending of the type of prosthesis. In conclusion, we identified both common and specific gait patterns in people with amputation, either regardless of, or according to their level of amputation and the type of prosthetic component.

Materials for lower limb prosthetic and orthotic interfaces and sockets: Evolution and associated skin problems

Introduction: Sockets and interfaces are important elements for lower limb orthoses and prostheses, as they allow for proper contact and fit between the devices and the affected limb or stump.Objective: To review the different polymers used in the development of lower limb sockets and external prosthetic and orthotic interfaces, their functional requirements and the possible skin problems caused by their use.Materials and methods: A literature review was conducted using the databases EBSCO, Embase, LILACS, SciELO, ScienceDirect and Scopus.Results: 47 articles and papers that met the inclusion criteria were retrieved. Thermoplastics, thermosets, foams, gels and elastomers are among the polymers used for manufacturing prosthetic and orthotic interfaces and sockets. However, studies estimate that between 32% and 90.9% of the population that use these devices have experienced skin problems on the affected stump or limb, such as excessive sweating, wounds and irritation.Conclusion: There is a clear need for further research to develop prosthetic and orthotic interfaces and sockets for lower limbs that can prevent or control damage to the skin of users.

Risk factors for amputation in patients with diabetic foot infection: a prospective study

There is a variety of diagnostic and therapeutic algorithms for diabetic foot infections (DFIs). Some of them are too difficult to be applied in routine clinical approach. In the routine clinical approach, it is necessary to find new risk factors and end up with a quick and easy assessment of DFIs. In this study, we aimed to evaluate the independent risk factors for osteomyelitis, amputation and major amputation in patients with DFI using standard scoring procedures. We prospectively studied 379 patients with DFI. The variables were analysed using logistic analysis. A total of 126 cases (33·2%) underwent amputation. The odds ratios in the amputation model were 3·09 for osteomyelitis (P < 0·001), 4·90 for arterial stenosis (AS) (P < 0·001), 3·67 for the history of DFI (P = 0·001), 2·47 for ulcer duration >60 days (P = 0·001), 3·10 for ulcer depth > 15 mm (P < 0·001) and 10·28 for fungal DFI (P = 0·015). In this study, the unusual result of well-known literature was fungal DFI as an independent risk factor for amputation in patients with DFI.

Rate of and Factors Associated with Ambulation After Unilateral Major Lower-Limb Amputation at an Urban US Tertiary-Care Hospital with a Multidisciplinary Limb Salvage Team

BACKGROUND

One relatively universal functional goal after major lower-limb amputation is ambulation in a prosthesis. This retrospective, observational investigation sought to 1) determine what percentage of patients successfully walked in a prosthesis within 1 year after major limb amputation and 2) assess which patient factors might be associated with ambulation at an urban US tertiary-care hospital.

METHODS

A retrospective medical record review was performed to identify consecutive patients undergoing major lower-limb amputation.

RESULTS

The overall rate of ambulation in a prosthesis was 29.94% (50.0% of those with unilateral below-the-knee amputation [BKA] and 20.0% of those with unilateral above-the-knee amputation [AKA]). In 24.81% of patients with unilateral BKA or AKA, a secondary surgical procedure of the amputation site was required. In those with unilateral BKA or AKA, statistically significant factors associated with ambulation included male sex (odds ratio [OR] = 2.50) and at least 6 months of outpatient follow-up (OR = 8.10), survival for at least 1 postoperative year (OR = 8.98), ambulatory preamputation (OR = 14.40), returned home after the amputation (OR = 6.12), and healing of the amputation primarily without a secondary surgical procedure (OR = 3.62). Those who had a history of dementia (OR = 0.00), a history of peripheral arterial disease (OR = 0.35), and a preamputation history of ipsilateral limb revascularization (OR = 0.14) were less likely to walk. We also observed that patients with a history of outpatient evaluation by a podiatric physician before major amputation were 2.63 times as likely to undergo BKA as opposed to AKA and were 2.90 times as likely to walk after these procedures.

CONCLUSIONS

These results add to the body of knowledge regarding outcomes after major amputation and could be useful in the education and consent of patients faced with major amputation.

Use of three-dimensional digital image correlation to evaluate mechanical response of prosthetic systems

BACKGROUND AND AIM

The need of comfortable and safe prosthetic systems is an important challenge for both prosthetists and engineers. The aim of this technical note is to demonstrate the use of three-dimensional digital image correlation to evaluate mechanical response of two prosthetic systems under real patient dynamic loads.

TECHNIQUE

This note describes the use of three-dimensional digital image correlation method to obtain full-field strain and displacement measurements on the surface of two lower limb prostheses for Chopart amputation. It outlines key points of the measurement protocol and illustrates the analysis of critical regions using data obtained on specific points of interest.

DISCUSSION

The results show that the use of three-dimensional digital image correlation can be a tool for the prosthetist to optimize the prosthesis considering features related to the material and design, in order to bear with real patient-specific load conditions. Clinical relevance Three-dimensional digital image correlation can support decision-making on new designs and materials for prosthetics based on quantitative data. Better understanding of mechanical response could also assist prescription for appropriate prosthetic systems.