The benefits of using a vacuum-assisted socket system to improve balance and gait in elderly transtibial amputees

An adaptive prosthetic socket for people with transtibial amputation

It is essential that people with limb amputation maintain proper prosthetic socket fit to prevent injury. Monitoring and adjusting socket fit, for example by removing the prosthesis to add prosthetic socks, is burdensome and can adversely affect users' function and quality-of-life. This study presents results from take-home testing of a motor-driven adaptive socket that automatically adjusted socket size during walking. A socket fit metric was calculated from inductive sensor measurements of the distance between the elastomeric liner surrounding the residual limb and the socket's inner surface. A proportional-integral controller was implemented to adjust socket size. When tested on 12 participants with transtibial amputation, the controller was active a mean of 68% of the walking time. In general, participants who walked more than 20 min/day demonstrated greater activity, less doff time, and fewer manual socket size adjustments for the adaptive socket compared with a locked non-adjustable socket and a motor-driven socket that participants adjusted with a smartphone application. Nine of 12 participants reported that they would use a motor-driven adjustable socket if it were available as it would limit their socket fit issues. The size and weight of the adaptive socket were considered the most important variables to improve.

Socket-residuum coupling integrity affects perception of external stimuli: Effects of altering the transtibial interface using vacuum-assisted suspension

BACKGROUND

Relative movement between the socket and residual limb can impair function in prosthesis users. It is plausible that, in addition to its mechanical effect, the integrity of the socket-residuum interface influences the ability of an individual to sense tactile cues through the prosthesis. Vacuum-assisted suspension (VAS) has been shown to reduce relative movement at this interface, providing a means to test this premise. The purpose of this pilot study was to assess the effects of altering socket-residuum interface integrity through the VAS pressure level on the thresholds of perception of an externally applied vibration stimulus.

METHODS

Seven unilateral transtibial prosthesis users participated. Socket-residual limb integrity was altered using the VAS subatmospheric (vacuum) pressure level. Vibration perception tests were conducted at low, mid, and high vacuum levels, targeting 0, 8, and 19 in Hg respectively, and performed in partially loaded and fully loaded conditions. Vibration intensity was increased using a dial until participants delivered a verbal signal indicating it was perceptible, and the nominal intensity was recorded.

RESULTS

Intensity thresholds decreased (ie, sensitivity increased) from low to high vacuum settings when fully loaded ( P = 0.008). Differences when partially loaded were nonsignificant and variable across participants.

CONCLUSION

This study provides preliminary evidence that altering the integrity between the socket and residual limb by modifying the vacuum level affects sensation related to the external environment experienced through the prosthesis, although translation of these findings to real-world stimuli remains to be tested.

Quantitative methods used to evaluate balance, postural control, and the fear of falling in lower limb prosthesis users: A systematic review

Problems with balance, postural control, and fear of falling are highly prevalent in lower limb prosthesis users, with much research conducted to understand these issues. The variety of tools used to assess these concepts presents a challenge when interpreting research outcomes. This systematic review aimed to provide a synthesis of quantifiable methods used in the evaluation of balance, postural control, and fear of falling in lower limb prosthesis users with an amputation level at or proximal to the ankle joint. A systematic search was conducted in CINAHL, Medline, AMED, Cochrane, AgeLine, Scopus, Web of Science, Proquest, PsycINFO, PsycArticles, and PubPsych databases followed by additional manual searching via reference lists in the reviewed articles databases. Included articles used quantitative measure of balance or postural control as one of the dependent variables, lower limb prosthesis users as a sample group, and were published in a peer-reviewed journal in English. Relevant assessment questions were created by the investigators to rate the assessment methods used in the individual studies. Descriptive and summary statistics are used to synthesize the results. The search yielded (n = 187) articles assessing balance or postural control (n = 5487 persons in total) and (n = 66) articles assessing fear of falling or balance confidence (n = 7325 persons in total). The most used test to measure balance was the Berg Balance Scale and the most used test to measure fear of falling was the Activities-specific Balance Confidence scale. A large number of studies did not present if the chosen methods were valid and reliable for the lower limb prosthesis users. Among study limitations, small sample size was common.

Daily socket comfort in transtibial amputee with a vacuum-assisted suspension system: study protocol of a randomized, multicenter, double-blind multiple N-of-1 trial

BACKGROUND

The main aim of this paper is to present the feasibility of rigorously designed multiple N-of-1 design in prosthetics research. While research of adequate power and high quality is often lacking in rehabilitation, N-of-1 trials can offer a feasible alternative to randomized controlled group trials, both increasing design power at group level and allowing a rigorous, statistically confirmed evaluation of effectiveness at a single patient level. The paper presents a multiple N-of-1 trial protocol, which aim is to evaluate the effectiveness of Unity, a prosthetic add-on suspension system for amputees, on patient-reported comfort during daily activities (main outcome measure), prosthesis wearing time, perception of limb-prosthesis fitting and stump volume and functional walking parameters.

METHODS

Multicenter, randomized, prospective, double-blind multiple N-of-1 trial using an introduction/withdrawal design alternating Unity connected/disconnected phases of randomized length on twenty patients with unilateral transtibial amputation. The primary outcome measure is the Prosthetic Socket Comfort Score (SCS), a validated measure of comfort, administered daily by an phone app designed for the study. Secondary outcomes measures will be collected during the 50 days period of the N-of-1 trial: (1) by the same app, daily for patient-reported limb-prosthesis fitting, stump volume variation, and daily wearing time of the prosthesis; (2) by a pedometer for the number of steps per day; (3) by blind assessors in the rehabilitation center during adjustment visits for functional walking parameter (L-Test, 6-minute walk test), and by the patient for the QUEST, and ABC-S. Effectiveness of the Unity system regarding SCS and daily secondary outcome measures will be tested by randomization test. The secondary outcome measures assessed during visits in the rehabilitation center will be analyzed by Non Overlap of All pairs. An estimate of the effect on the amputee population will be generated by aggregating each individual clinical trial (N-of-1 trial) by Hierarchical Bayesian methods.

DISCUSSION

This study protocol was designed to answer the question "which device is best for THIS patient" and to conclude at a group level on the effectiveness of a new devic, using a Multiple N-of-1 trial, which is promising but underused in prosthetics research so far.

TRIAL REGISTRATION

N° ID-RCB 2020-A01309-30 Clintrial.gov : NCT04804150 - Retrospectively registered March 20th 2021.

A Modified Version of the Forgotten Joint Score-12 in Lower Limb Amputees: Validity and Reliability Study

Adaptation to prosthesis is important for occupation, quality of life, and participation in social life, so it needs to be evaluated. The aim of this study was to determine the validity and reliability of the Forgotten Joint Score-12 (FJS-12) in lower limb amputees. The FJS-12 was applied to 80 amputees. Criterion-referenced validity was assessed using the activity restriction subparameter of Trinity Amputation and Prosthesis Experience Scale (TAPES). The internal consistency of the FJS-12 was high (Cronbach's α = .943). A statistically significant very good negative correlation was determined between the FJS-12 and the activity restriction subparameter of TAPES (r = -.641; p < .001). The results of this study showed that FJS-12 is a valid and reliable measurement tool that can be used to assess the adaptation to prosthesis in amputees. Evaluation of prosthesis awareness in daily living activities of amputees is important in terms of establishing occupational therapy and rehabilitation programs.

Osseointegrated prostheses improve balance and balance confidence in individuals with unilateral transfemoral limb loss

BACKGROUND

More than half of patients with lower-limb amputation who use socket prostheses experience at least one fall annually. These falls are primarily attributed to reduced proprioception which negatively affects balance. A promising alternative to socket prostheses are osseointegrated prostheses that involve direct fixation of the prosthetic limb to the residual limb through a bone-anchored implant, yet its effect on balance remains unknown.

RESEARCH QUESTION

Do osseointegrated prostheses change static and dynamic balance, as well as patient reported measures of balance confidence, compared to a socket prosthesis?

METHODS

A sample of 10 patients with unilateral transfemoral amputation scheduled to undergo prosthesis osseointegration were enrolled (6 F/4 M, BMI: 26.7 ± 2.9 kg/m2, Age: 46.1 ± 6.3 years). Motion capture data during quiet standing (eyes opened and eyes closed) and overground walking at a self-selected speed, and the Activities-Specific Balance Confidence (ABC) scale, were collected before (with socket prosthesis) and 12-months following osseointegration. Postural sway via the center of pressure (COP), variability of spatiotemporal parameters, and ABC scores were compared using a repeated measures design before and after osseointegration.

RESULTS

Following prosthesis osseointegration, COP path length and 95 % confidence ellipse area were reduced during quiet standing (d = 0.75, P = 0.09; d = 0.52, P = 0.29, respectively) and the variability of step width and length were reduced during overground walking (d = 0.50, P = 0.06; d = 0.72, P = 0.06, respectively). Furthermore, patients reported significantly improved ABC scores with an osseointegrated prosthesis compared to a socket prosthesis (d = -1.36, P = 0.01).

SIGNIFICANCE

Improvements in postural sway, reductions in gait variability, and greater balance confidence indicate that osseointegrated prostheses improve balance for people with unilateral transfemoral amputation.

Spatiotemporal gait patterns in individuals with unilateral transfemoral amputation: A hierarchical cluster analysis

Gait pattern classification in individuals with lower-limb amputation could help in developing personalized prosthetic prescriptions and tailored gait rehabilitation. However, systematic classifications of gait patterns in this population have been scarcely explored. This study aimed to determine whether the gait patterns in individuals with unilateral transfemoral amputation (UTFA) can be clustered into homogeneous subgroups using spatiotemporal parameters across a range of walking speeds. We examined spatiotemporal gait parameters, including step length and cadence, in 25 individuals with UTFA (functional level K3 or K4, all non-vascular amputations) while they walked on a split-belt instrumented treadmill at eight speeds. Hierarchical cluster analysis (HCA) was used to identify clusters with homogeneous gait patterns based on the relationships between step length and cadence. Furthermore, after cluster formation, post-hoc analyses were performed to compare the spatiotemporal parameters and demographic data among the clusters. HCA identified three homogeneous gait pattern clusters, suggesting that individuals with UTFA have several gait patterns. Further, we found significant differences in the participants' body height, sex ratio, and their prosthetic knee component among the clusters. Therefore, gait rehabilitation should be individualized based on body size and prosthetic prescription.

Mechanically and physiologically optimizing prosthetic elevated vacuum systems in people with transtibial amputation: a pilot study

Introduction

The most suitable elevated vacuum (EV) pressure may differ for each individual prosthesis user depending on suspension needs, socket fit, prosthetic components, and health. Mechanical and physiological effects of EV were evaluated in an effort to determine the optimal vacuum pressure for three individuals.

Methods

Instrumented EV sockets were created based on the participants' regular EV sockets. Inductive distance sensors were embedded into the wall of the socket at select locations to measure limb movement relative to the socket. Each participant conducted an activity protocol while limb movement, limb fluid volume, and user-reported comfort were measured at various socket vacuum pressure settings.

Results

Increased socket vacuum pressure resulted in reduced limb-socket displacement for each participant; however, 81-93% of limb movement was eliminated by a vacuum pressure setting of 12 (approximately -9 inHg). Relative limb-socket displacement by sensor location varied for each participant, suggesting distinct differences related to socket fit or residual limb tissue content. The rate of limb fluid volume change and the change in socket comfort did not consistently differ with socket vacuum pressure, suggesting a more complex relationship unique to each individual.

Conclusions

Practitioners may use individual responses to optimize socket vacuum pressure settings, balancing mechanical and physiological effects of EV for improved clinical outcomes.

Effects of a modified passive socket system on short-term changes in residuum volume and comfort: A preliminary study in transtibial amputees

BACKGROUND

Changes in residuum volume are a common problem in lower-limb amputees during prosthesis usage, and can lead to poor suspension, impaired gait, and tissue damage. Residuum volume can be affected by the in-socket air pressure, which will influence fluid flow in and around the residuum. The use of "active" pumps to reduce air pressure has been shown to conserve the residuum volume, but these are expensive and unlikely to be widely available. An alternative, passive approach, based on Boyles' law, is to introduce a larger distal void volume at the end of the socket and hence reduce the change in pressure for a given change in volume.

OBJECTIVES

To compare the performance across three test conditions (passive-conventional, with standard distal void; passive-with increased distal void; and active system) in terms of residuum volume changes and comfort.

STUDY DESIGN

Repeated-measures experiment under three test conditions.

METHODS

Five transtibial amputee participants (three males and two females), aged between 27 and 67 years, and of mobility grade K2 or K3, were fitted with a bespoke test prosthesis that was adapted to include the three test conditions. Residuum volume was measured before and after walking under each test condition (presented in a random order). Comfort was also assessed after walking with each test condition.

RESULTS

The reduction in residuum volume, relative to the baseline volume, was higher for the conventional passive system (4.2% ± 2.8%) compared with the modified passive (1.4% ± 1.4%) and active (1.6% ± 1.1%) systems.

CONCLUSION

The use of a passive suspension system with an increased distal void within the socket may help to stabilize the residuum volume during prosthesis usage.

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

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

The effects of ground-irregularity-cancelling prosthesis control on balance over uneven surfaces

Over half of individuals with a lower-limb amputation are unable to walk on uneven terrain. Using a prosthesis emulator system, we developed an irregularity-cancelling controller intended to reduce the effect of disturbances resulting from uneven surfaces. This controller functions by changing the neutral angles of two forefoot digits in response to local terrain heights. To isolate the effects of the controller, we also programmed a spring-like controller that maintained fixed neutral angles. Five participants with transtibial amputation walked on a treadmill with an uneven walking surface. Compared with the spring-like controller, the irregularity-cancelling controller reduced ankle torque variability by 41% in the sagittal plane and 64% in the frontal plane. However, user outcomes associated with balance were mostly unaffected; only trunk movement variability was reduced, whereas metabolic rate, mediolateral centre of mass motion, and variabilities in step width, step length and step time were unchanged. We conclude that reducing ankle torque variability of the affected limb is not sufficient for reducing the overall effect of disturbances due to uneven terrain. It is possible that other factors, such as changes in step height or disturbances to the intact limb, play a larger role in difficulty balancing while walking over uneven surfaces.

Lower limb prosthetic interfaces: Clinical and technological advancement and potential future direction

The human-prosthesis interface is one of the most complicated challenges facing the field of prosthetics, despite substantive investments in research and development by researchers and clinicians around the world. The journal of the International Society for Prosthetics and Orthotics, Prosthetics and Orthotics International, has contributed substantively to the growing body of knowledge on this topic. In celebrating the 50th anniversary of the International Society for Prosthetics and Orthotics, this narrative review aims to explore how human-prosthesis interfaces have changed over the last five decades; how research has contributed to an understanding of interface mechanics; how clinical practice has been informed as a result; and what might be potential future directions. Studies reporting on comparison, design, manufacturing and evaluation of lower limb prosthetic sockets, and osseointegration were considered. This review demonstrates that, over the last 50 years, clinical research has improved our understanding of socket designs and their effects; however, high-quality research is still needed. In particular, there have been advances in the development of volume and thermal control mechanisms with a few designs having the potential for clinical application. Similarly, advances in sensing technology, soft tissue quantification techniques, computing technology, and additive manufacturing are moving towards enabling automated, data-driven manufacturing of sockets. In people who are unable to use a prosthetic socket, osseointegration provides a functional solution not available 50 years ago. Furthermore, osseointegration has the potential to facilitate neuromuscular integration. Despite these advances, further improvement in mechanical features of implants, and infection control and prevention are needed.

Modeling the mechanics of elevated vacuum systems in prosthetic sockets

Elevated vacuum (EV) is suggested to improve suspension and limb volume management for lower limb prosthesis users. However, few guidelines have been established to facilitate configuration of EV sockets to ensure their safe and proper function. A benchtop model of an EV socket was created to study how prosthetic liner tensile elasticity, socket fit, and socket vacuum pressure affect liner displacement and subsequent pressure on the residual limb. A domed carbon fiber layup was used to represent an EV socket. Inserts were used to simulate various air gaps between the socket and liner. Various prosthetic liner samples were placed under the carbon fiber layup. Liner displacement and the corresponding pressure change underneath the liner were measured as vacuum was applied between the liner sample and socket wall. Tissue vacuum pressure increased linearly with socket vacuum pressure until the liner contacted the socket wall. Predicted tissue vacuum pressure matched well with experimental results. Findings suggest that the effect of vacuum pressure on the residual limb is primarily determined by air gap distance. The developed model may be used to assess effects of EV on residual limb tissues based on an individual's socket fit, liner characteristics, and applied vacuum. Understanding the physiological effects of EV on the residual limb could help practitioners avoid blister formation and improve EV implementation.

Does actively enlarging socket volume during resting facilitate residual limb fluid volume recovery in trans-tibial prosthesis users?

BACKGROUND

Residual limb volume loss is a source of prosthetic socket fit problems in people with lower-limb amputation. The aim of this study was to investigate a novel volume recovery strategy for people with trans-tibial amputation.

METHODS

Test sockets for people with trans-tibial amputation were created that allowed panels of an adjustable socket and the underlying elastomeric liner to be pulled radially outward, using small motors mounted to the socket. One Control and one Intervention session were conducted with each participant. During Intervention sessions, panel-pull was executed during the sits of a multi-cycle sit/walk protocol. No panel-pull was executed during the Control sessions. Residual limb fluid volume was monitored in anterior and posterior regions using bioimpedance analysis.

FINDINGS

Results from 12 participants demonstrated that short-term (12 min after the intervention was applied) median posterior residual limb fluid volume change for Intervention (0.44%) was higher than that for Control (-0.02%) (P = .015). Long-term (40 min after the intervention was applied) median posterior residual limb fluid volume change for Intervention (0.95%) was higher than that for Control (-0.26%) (P = .002).

INTERPRETATION

If a panel-pull mechanism that was easy to assemble and operate could be created, then panel-pull may be an effective accommodation strategy to reduce daily limb volume loss in trans-tibial prosthesis users.

Effect of electrical stimulation of receptive fields in people with lower limb amputation on variables of gait

People with amputation may perceive phantom limb sensations or pain in the amputated body part when ipsilateral body-regions are stimulated. These body-regions are called receptive fields. This study assessed whether receptive fields change in size and position over the course of one month in people with trans-tibial amputation and whether electrical stimulation of these fields in synchrony with walking affects phantom sensations and variables of gait. Thirty-one subjects participated in this study. Receptive fields were mapped seven times over a one month period. Thereafter, the effect of electrical stimulation in synchrony with walking was compared to placebo stimulation in an acute setting with a randomized, single-blind gait analysis in 18 participants. Results showed that receptive field size and position presented an adequate degree of consistency (difference in point of first response position of 4.9 ± 4.8 cm and overlap of total receptive field area of 54.3 ± 35.0 %) for future use of electrical stimulation. Gait parameters for everyday activities (speed, gait width, % stance and swing phase) as well as perception of phantom pain were not altered to a clinically relevant degree by electrical stimulation and no negative effects were reported. In conclusion: Location and size of receptive fields are consistent enough for daily electrical stimulation without laborious daily assessment. If applied acutely, no significant effect on gait or pain could be detected. However, results are promising enough to test chronic application of electrical stimulation during gait in a long-term setting.

Prosthetic rehabilitation for older dysvascular people following a unilateral transfemoral amputation

BACKGROUND

Dysvascularity accounts for 75% of all lower limb amputations in the UK. Around 37% of these procedures are done at the transfemoral level (mid-thigh), with most patients over the age of 60 and having existing comorbidities. A significant number of these amputees are prescribed a lower limb prosthesis for walking. However, many amputees do not achieve a high level of function following prosthetic rehabilitation. This is the third update of the review first published in 2005.

OBJECTIVES

To identify and summarise the evidence evaluating prosthetic rehabilitation interventions for prosthetic ambulation following unilateral transfemoral or transgenicular amputation in older dysvascular people, whether community dwelling or institutionalised.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register and CENTRAL, MEDLINE, Embase, and CINAHL databases; the World Health Organization International Clinical Trials Registry Platform; and the ClinicalTrials.gov trials registry to 14 June 2018. We performed additional searches by handsearching citations of studies identified by the electronic search. We applied no restrictions on language or publication status.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials testing prosthetic rehabilitation interventions following a unilateral transfemoral or transgenicular amputation in older (aged 60 years or older) dysvascular people.

DATA COLLECTION AND ANALYSIS

Two review authors independently scanned the search results for potentially eligible studies and, on obtaining full reports of these, selected studies for inclusion and exclusion. Two review authors independently assessed the methodological quality of studies and extracted data. We used GRADE to assess the overall quality of evidence supporting the outcomes assessed in this review.

MAIN RESULTS

We identified no new studies for inclusion in this update. In total we included one trial, excluded 18 trials, classed one trial as ongoing, and classed another as awaiting classification. The total number of participants in the included trial was 10, and the methodological quality of this trial was moderate because of high risk of bias in relation to two domains (random sequence generation and allocation concealment) but low risk of bias for the four remaining domains (blinding, incomplete outcome data, selective reporting, and any other bias). The included trial was a short-term cross-over randomised trial undertaken in Canada, which tested the effects of adding three seemingly identical prosthetic weights (150 g vs 770 g vs 1625 g) to the prostheses of a total of 10 participants with unilateral dysvascular transfemoral amputation. Eight participants were over 60 years of age. Trial authors found that four participants preferred the addition of the lightest weight (150 g), five preferred the middle weight (770 g), and one preferred the heaviest weight (1625 g). Researchers interpreted this as equating to user satisfaction (success) and reported no adverse effects.

AUTHORS' CONCLUSIONS

The limited evidence presented in this review is of very low quality and is insufficient to inform the choice of prosthetic rehabilitation, including the optimum weight of the prosthesis, after unilateral transfemoral amputation in older dysvascular people. A programme of research that includes randomised controlled trials to examine key interventions is urgently required in this area.

Real time monitoring of transtibial elevated vacuum prostheses: A case series on socket air pressure

Prosthetic elevated vacuum is a suspension method used to reduce daily volume changes of the residual limb. Evaluation of the effectiveness of these systems is limited due to a lack of correlation to actual socket air pressure, particularly during unconstrained movements. This may explain some of the variability in functional outcomes reported in the literature. Our objective was to develop a light-weight portable socket measurement system to quantify internal socket air pressure, temperature, and acceleration; and to present preliminary results from implementation with three transtibial prosthesis users with mechanical elevated vacuum pumps. Participants completed five functional tasks with and without the vacuum pumps actively connected, including the 2-Minute Walk test, 5-Times Sit-to-Stand test, 4-Square Step test, L-Test, and Figure-8 test. Results demonstrated different gait profiles and pressure ranges for each user. Two of the participants demonstrated substantially lower air pressure (higher vacuum) over time while the pump was active compared to inactive. The minimum air pressure measured for all participants was -34.6 ± 7.7 kPa. One participant did not show substantial changes in pressure over time for either pump condition. Functional task performance was not significantly different between pump conditions. Correlation with accelerometer readings indicated peak positive pressures occurred just following initial contact of the foot in early stance, and the most negative pressures (highest vacuum) were observed throughout swing. This study has demonstrated the use of a portable data logging tool that may serve the clinical and research communities to quantify the operation of elevated vacuum systems, and better understand the variability of mechanical pump operation and overall system performance.

Prosthesis satisfaction in lower limb amputees: A systematic review of associated factors and questionnaires

BACKGROUND

Factors influencing patient satisfaction with a transtibial prosthesis have been studied fragmentarily. The aims of this systematic review were to review the literature regarding factors of influence on patient satisfaction with a transtibial prosthesis, to report satisfaction scores, to present an overview of questionnaires used to assess satisfaction and examine how these questionnaires operationalize satisfaction.

METHODS

A literature search was performed in PubMed, Embase, PsycInfo, CINAHL, Cochrane, and Web of Knowledge databases up to February 2018 to identify relevant studies.

RESULTS

Twelve of 1832 studies met the inclusion criteria. Sample sizes ranged from 14 to 581 participants, mean age ranged from 18 to 70 years, and time since amputation ranged from 3 to 39 years. Seven questionnaires assessed different aspects of satisfaction. Patient satisfaction was influenced by appearance, properties, fit, and use of the prosthesis, as well as aspects of the residual limb. These influencing factors were not relevant for all amputee patients and were related to gender, etiology, liner use, and level of amputation. No single factor was found to significantly influence satisfaction or dissatisfaction. Significant associations were found between satisfaction and gender, etiology, liner use, and level of amputation.

CONCLUSION

Relevance of certain factors for satisfaction was related to specific amputee patient groups. Questionnaires assessing satisfaction use different operationalizations, making comparisons between studies difficult.

Balance-confidence is associated with community participation, perceived physical mobility, and performance-based function among individuals with a unilateral amputation

OBJECTIVE

To explore relationships between balance-confidence and: 1) community participation; 2) self-perceived mobility; and 3) performance-based physical function among individuals with a lower-limb amputation using a prosthetic. Design: Retrospective, cross-sectional study. Setting: Outpatient, multidisciplinary amputee clinic. Participants: Patients (n = 45) using a prosthesis, aged ≥ 18 years, with a unilateral transfemoral or transtibial amputation of ≥1 year, were included. Methods: Participants completed the following self-report measures: Activities-Specific Balance Confidence Scale (ABC); Community Integration Questionnaire (CIQ); Locomotor Capabilities Index (LCI); and two performance-based measures (i.e. Timed Up and Go and 6 Minute Walk Test). Linear regression modeling was used to explore relationships between balance-confidence (i.e. ABC) and self-report (i.e. CIQ and LCI) and performance-based measures (p ≤ 0.0125). Results: After controlling for potential covariates (i.e. age, sex, and body mass index), balance-confidence explained 47.4% of the variance in CIQ (p = 0.000), 53.0% of the variance in LCI (p = 0.000), 20.3% of the variance in Timed Up and Go (p = 0.001), and 18.2% of the variance in 6 Minute Walk Test (p = 0.001). Conclusion: Lower balance-confidence is associated with less community participation, lower self-perceived mobility, and poorer performance among patients with a unilateral lower-limb amputation.

Effects of the unity vacuum suspension system on transtibial gait for simulated non-level surfaces

Walking on various surfaces encountered in everyday life requires lower limb prosthesis users to continually adapt their movement patterns. Elevated vacuum suspension systems could improve transtibial amputee gait on non-level surfaces; however, research is lacking to guide clinical practice. Twelve transtibial amputees were fitted with the Össur sleeveless vacuum suspension system (Unity). After a one month accommodation period, the CAREN-Extended system was used to evaluate gait on a self-paced treadmill when walking with continuous perturbations (medial-lateral translations, rolling hills, simulated uneven ground) with an active or inactive vacuum suspension system. Significant differences between active and inactive vacuum conditions (p<0.05) were found for some temporal-spatial and kinematic gait parameters, but the differences were small and not considered clinically significant. Our findings suggest that potential vacuum pump failures would not immediately affect gait performance in a moderately high functioning amputee population. However, residual limb volume changes over time due to the removal of elevated vacuum may adversely affect socket fit, leading to greater gait differences and reduced quality of life.

Elevated vacuum suspension preserves residual-limb skin health in people with lower-limb amputation: Randomized clinical trial

A growing number of clinical trials and case reports support qualitative claims that use of an elevated vacuum suspension (EVS) prosthesis improves residual-limb health on the basis of self-reported questionnaires, clinical outcomes scales, and wound closure studies. Here, we report first efforts to quantitatively assess residual-limb circulation in response to EVS. Residual-limb skin health and perfusion of people with lower-limb amputation (N = 10) were assessed during a randomized crossover study comparing EVS with nonelevated vacuum suspension (control) over a 32 wk period using noninvasive probes (transepidermal water loss, laser speckle imaging, transcutaneous oxygen measurement) and functional hyperspectral imaging approaches. Regardless of the suspension system, prosthesis donning decreased perfusion in the residual limb under resting conditions. After 16 wk of use, EVS improved residual-limb oxygenation during treadmill walking. Likewise, prosthesis-induced reactive hyperemia was attenuated with EVS following 16 wk of use. Skin barrier function was preserved with EVS but disrupted after control socket use. Taken together, outcomes suggest chronic EVS use improves perfusion and preserves skin barrier function in people with lower-limb amputation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; "Evaluation of limb health associated with a prosthetic vacuum socket system": NCT01839123; https://clinicaltrials.gov/ct2/show/NCT01839123?term=NCT01839123&rank=1.

Clinical evaluation of a prosthetic suspension system: Looped silicone liner

OBJECTIVES

This study aimed to evaluate and compare a newly designed suspension system with a common suspension in the market.

STUDY DESIGN

Prospective study.

METHODS

Looped liners with hook fastener and Iceross Dermo Liner with pin/lock system were mechanically tested using a tensile testing machine in terms of system safety. A total of 10 transtibial amputees participated in this study and were asked to use these two different suspension systems. The pistoning was measured between the liner and socket through a photographic method. Three static axial loading conditions were implemented, namely, 30, 60, and 90 N. Furthermore, subjective feedback was obtained.

RESULTS

Tensile test results showed that both systems could safely tolerate the load applied to the prosthesis during ambulation. Clinical evaluation confirmed extremely low pistoning in both systems (i.e. less than 0.4 cm after adding 90 N traction load to the prosthesis). Subjective feedback also showed satisfaction with both systems. However, less traction at the end of the residual limb was reported while looped liner was used.

CONCLUSION

The looped liner with hook fastener is safe and a good alternative for individuals with transtibial amputation as this system could solve some problems with the current systems. Clinical relevance The looped liner and hook fastener were shown to be good alternative suspension for people with lower limb amputation especially those who have difficulty to use and align the pin/lock systems. This system could safely tolerate centrifugal forces applied to the prosthesis during normal and fast walking.

Progress Toward Optimizing Prosthetic Socket Fit and Suspension Using Elevated Vacuum to Promote Residual Limb Health

Objective: Prosthetic sockets are custom made for each amputee, yet there are no quantitative tools to determine the appropriateness of socket fit. Ensuring a proper socket fit can have significant effects on the health of residual limb soft tissues and overall function and acceptance of the prosthetic limb. Previous work found that elevated vacuum pressure data can detect movement between the residual limb and the prosthetic socket; however, the correlation between the two was specific to each user. The overall objective of this work is to determine the relationship between elevated vacuum pressure deviations and prosthetic socket fit. Approach: A tension compression machine was used to apply repeated controlled forces onto a residual limb model with sockets of different internal volume. Results: The vacuum pressure-displacement relationship was dependent on socket fit. The vacuum pressure data were sensitive enough to detect differences of 1.5% global volume and can likely detect differences even smaller. Limb motion was reduced as surface area of contact between the limb model and socket was maximized. Innovation: The results suggest that elevated vacuum pressure data provide information to quantify socket fit. Conclusions: This study provides evidence that the use of elevated vacuum pressure data may provide a method for prosthetists to quantify and monitor socket fit. Future studies should investigate the relationship between socket fit, limb motion, and limb health to define optimal socket fit parameters.

The evidence-base for elevated vacuum in lower limb prosthetics: Literature review and professional feedback

BACKGROUND

An optimal suspension system can improve comfort and quality of life in people with limb loss. To guide practice on prosthetic vacuum suspension systems, assessment of the current evidence and professional opinion are required.

METHODS

PubMed, Web of Science, and Google Scholar databases were explored to find related articles. Search terms were amputees, artificial limb, prosthetic suspension, prosthetic liner, vacuum, and prosthesis. The results were refined by vacuum socket or vacuum assisted suspension or sub-atmospheric suspension. Study design, research instrument, sample size, and outcome measures were reviewed. An online questionnaire was also designed and distributed worldwide among professionals and prosthetists (www.ispoint.org, OANDP-L, LinkedIn, personal email).

FINDINGS

26 articles were published from 2001 to March 2016. The number of participants averaged 7 (SD=4) for transtibial and 6 (SD=6) for transfemoral amputees. Most studies evaluated the short-term effects of vacuum systems by measuring stump volume changes, gait parameters, pistoning, interface pressures, satisfaction, balance, and wound healing. 155 professionals replied to the questionnaire and supported results from the literature. Elevated vacuum systems may have some advantages over the other suspension systems, but may not be appropriate for all people with limb loss.

INTERPRETATION

Elevated vacuum suspension could improve comfort and quality of life for people with limb loss. However, future investigations with larger sample sizes are needed to provide strong statistical conclusions and to evaluate long-term effects of these systems.

Physical activity, ambulation, and comorbidities in people with diabetes and lower-limb amputation

We characterized physical activity (PA) and its relation to physical function and number of comorbidities in people with diabetes and transtibial amputation (AMP), people with diabetes without AMP, and nondisabled adults without diabetes or AMP. Twenty-two individuals with type 2 diabetes mellitus (DM) and transtibial amputation (DM+AMP), 11 people with DM, and 13 nondisabled participants were recruited for this cross-sectional cohort study. Measures included PA volume and intensity, a Timed Up and Go test, a 2-min walk test, and number of comorbidities. The nondisabled group performed greater amounts of PA than the DM group, who performed greater amounts of PA than the DM+AMP group. PA was related to physical function in the DM group and in the DM+AMP group, whereas no such relationship existed in the nondisabled group. PA was not related to number of comorbidities in any group. These findings suggest the ability to walk may affect overall performance of PA. Alternately, PA may alleviate walking problems. This possibility is of interest because issues with walking may be modifiable by improved levels and intensity of PA. PA's lack of relation to number of comorbidities suggests that factors beyond multiple morbidities account for group differences in PA.