Construct Validity of the Prosthetic Limb Users Survey of Mobility (PLUS-M) in Adults With Lower Limb Amputation

Amputation-specific and generic correlates of participation among Veterans with lower limb amputation

Participation in valued interpersonal and community activities is a key component of rehabilitation for Veterans with amputation. The purpose of this study was to identify specific factors that promote or inhibit participation to inform development of interventions that may facilitate participation in desired life activities. A convenience sample of 408 Veterans with at least one lower limb amputation and who had received outpatient care from the Regional Amputation Center (RAC) completed a mailed survey. Participation was measured using the Community Participation Indicators (CPI) Importance, Control, and Frequency scales and the Patient Reported Outcome Measurement Information System (PROMIS) Ability to Participate in Social Roles and Satisfaction with Social Participation scales. Multiple imputation procedures were used to address missing data. Correlates of participation were examined through multiple linear regression. A total of 235 participants completed the survey, a response rate of 58%. Levels of participation, measured with the PROMIS instruments, were 43.2 (SD = 8.1) for Ability and 46.4 (SD = 8.6) for Satisfaction. Regression analyses found robust amputation-specific correlates for participation, including body image and balance confidence. Generic (non-amputation specific) correlates for participation included depression and pain interference. Development of treatment approaches and devices that can address body image, balance confidence, pain, and mental health concerns such as depression have the potential to enhance the participation and rehabilitation of Veterans with lower limb amputation.

Direction of attentional focus in prosthetic training: Current practice and potential for improving motor learning in individuals with lower limb loss

OBJECTIVE

Adopting an external focus of attention has been shown to benefit motor performance and learning. However, the potential of optimizing attentional focus for improving prosthetic motor skills in lower limb prosthesis (LLP) users has not been examined. In this study, we investigated the frequency and direction of attentional focus embedded in the verbal instructions in a clinical prosthetic training setting.

METHODS

Twenty-one adult LLP users (8 female, 13 male; 85% at K3 level; mean age = 50.5) were recruited from prosthetic clinics in the Southern Nevada region. Verbal interactions between LLP users and their prosthetists (mean experience = 10 years, range = 4-21 years) during prosthetic training were recorded. Recordings were analyzed to categorize the direction of attentional focus embedded in the instructional and feedback statements as internal, external, mixed, or unfocused. We also explored whether LLP users' age, time since amputation, and perceived mobility were associated with the proportion of attentional focus statements they received.

RESULTS

We recorded a total of 20 training sessions, yielding 904 statements of instruction from 338 minutes of training. Overall, one verbal interaction occurred every 22.1 seconds. Among the statements, 64% were internal, 9% external, 3% mixed, and 25% unfocused. Regression analysis revealed that female, older, and higher functioning LLP users were significantly more likely to receive internally-focused instructions (p = 0.006, 0.035, and 0.024, respectively).

CONCLUSIONS

Our results demonstrated that verbal instructions and feedback are frequently provided to LLP users during prosthetic training. Most verbal interactions are focused internally on the LLP users' body movements and not externally on the movement effects.

IMPACT STATEMENT

While more research is needed to explore how motor learning principles may be applied to improve LLP user outcomes, clinicians should consider adopting the best available scientific evidence during treatment. Overreliance on internally-focused instructions as observed in the current study may hinder prosthetic skill learning.

Feasibility testing of a novel prosthetic socket sensor system

PURPOSE

Poorly fitting prosthetic sockets contribute to decreased quality of life, health, and well-being for persons with amputations. Therefore, improved socket fit is a high clinical priority.

METHODS

In this study, we describe the design and testing of a novel sensor system that can be incorporated into a prosthetic socket to measure distal end weight bearing in the socket and can alert a prosthesis user if poor socket fit is suspected. We present the results of testing this device with three Veterans who were new prosthesis users and three Veterans who were experienced prosthesis users.

RESULTS AND CONCLUSIONS

We collected sensor data during walking trials while participants wore varying numbers of sock plies and qualitative feedback on the design of the socket fit sensor system. For analysis, peak sensor measurements during walking cycles were identified and combined with socket fit data (i.e., a clinician-determined level of "good," "too tight," or "too loose" and the number of sock ply worn each trial). We found consistent relationships between peak sensor measurements and socket fit in our sample. Also, all users expressed an interest in the device, highlighting its potential benefits during early prosthesis training.Implications for RehabilitationEnsuring socket fit is challenging for many prosthesis users.A novel wearable sensor system can be used to identify socket fit issues for some prosthesis users.This type of system could be most helpful for new prosthesis users and those with sensory and cognitive challenges.

Normalization alters the interpretation of hip strength in established unilateral lower limb prosthesis users

BACKGROUND

Valid comparisons of muscle strength between individuals or legs that differ in size requires normalization, often by simple anthropometric variables. Few studies of muscle strength in lower-limb prosthesis users have normalized strength data by any anthropometric variable, potentially confounding our understanding of strength deficits in lower-limb prosthesis users. The objective of this pilot study was to determine the need for as well as effectiveness and impact of normalizing hip strength in lower-limb prosthesis users.

METHODS

Peak isometric hip extension and abduction torques were collected from 28 lower-limb prosthesis users. Allometric scaling was used to determine if hip torque values were significantly associated with, and therefore needed to be adjusted for, body mass, thigh length, or body mass x thigh length, and whether normalization was effective in reducing any associations. Between limb differences in peak hip torque, and correlations with balance ability, were inspected pre- and post-normalization.

FINDINGS

Hip torques were consistently and significantly associated with body-mass x thigh length. Associations between peak hip torque and body-mass x thigh length were reduced by normalization. After normalization by body-mass x thigh length, between limb differences in hip extension torque, as well as the correlation between hip abduction torque and balance ability, changed from non-significant to significant.

INTERPRETATION

In the absence of normalization, hip strength (i.e., peak torque) in lower-limb prosthesis users remains dependent on basic anthropometric variables, masking relationships between hip strength and balance ability, as well as between limb differences.

A concern for falling impacts quality of life for people with a lower limb amputation

The purpose of this web-based survey study was to comprehensively evaluate subdomains of concern for falling and its association with quality of life (QoL) among people with lower-limb amputations (PLLA). Forty-eight adults (mean 61.8 ± 11.6 years) with a major (i.e. transtibial or transfemoral) amputation participated. Individuals were currently using a prosthesis for ambulation, completed a prosthetic rehabilitation program, had functional use of English and had access to an internet-connected device (e.g. laptop). Five standardized scales assessed a concern for falling: Modified Survey of Activities and Fear of Falling in the Elderly (mSAFFE), Activities-specific Balance Confidence (ABC) Scale, Prosthetic Limb Users Survey - Mobility (PLUS-M), Consequences of Falling Scale and Perceived Ability to Manage Falls Scale. QoL was evaluated using the WHO QoL-100 questionnaire. Spearman correlation analysis evaluated the relationship between the five concerns for falling scales. Five independent linear regression modeling evaluated the association of each concern for falling measure on QoL. Strong statistically significant correlations were found between mSAFFE and PLUS-M (rs = -0.87; P < 0.05). Three scales were significantly associated with QoL: mSAFFE [-1.16 (95% CI, -2.04 to -0.29)], ABC [0.36 (95% CI, 0.11-0.61)] and PLUS-M [0.50 (95% CI, 0.05-0.95)]. This is the first study to evaluate multiple concerns for falling subdomains among PLLA. Concern for falling should be addressed in prosthetic rehabilitation to improve community re-integration and QoL.

Disparities in functional recovery after dysvascular lower limb amputation are associated with employment status and self-efficacy

PURPOSE

Employment status is considered a determinant of health, yet returning to work is frequently a challenge after lower limb amputation. No studies have documented if working after lower limb amputation is associated with functional recovery. The study's purpose was to examine the influence of full-time employment on functioning after lower limb amputation.

METHODS

Multisite, cross-sectional study of 49 people with dysvascular lower limb amputation. Outcomes of interest included performance-based measures, the Component Timed-Up-and-Go test, the 2-min walk test, and self-reported measures of prosthetic mobility and activity participation.

RESULTS

Average participant age was 62.1 ± 9.7 years, 39% were female and 45% were persons of color. Results indicated that 80% of participants were not employed full-time. Accounting for age, people lacking full-time employment exhibited significantly poorer outcomes of mobility and activity participation. Per regression analyses, primary contributors to better prosthetic mobility were working full-time (R² ranging from 0.06 to 0.24) and greater self-efficacy (R² ranging from 0.32 to 0.75).

CONCLUSIONS

This study offers novel evidence of associations between employment and performance-based mobility outcomes after dysvascular lower limb amputation. Further research is required to determine cause-effect directionalities. These results provide the foundation for future patient-centered research into how work affects outcomes after lower limb amputation. IMPLICATIONS FOR REHABILITATIONLower limb amputation can pose barriers to employment and activity participation, potentially affecting the quality of life.This study found that the majority of people living with lower limb amputation due to dysvascular causes were not employed full-time and were exhibiting poorer prosthetic outcomes.Healthcare practitioners should consider the modifiable variable of employment when evaluating factors that may affect prosthetic mobility.The modifiable variable of self-efficacy should be assessed by healthcare professionals when evaluating factors that may affect prosthetic mobility.

Measurements of Best, Worst, and Average Socket Comfort Are More Reliable Than Current Socket Comfort in Established Lower Limb Prosthesis Users

OBJECTIVE

To evaluate test-retest reliability and related measurement properties of items developed to assess best, worst, and average prosthetic socket comfort.

DESIGN

Methodological research to assess test-retest reliability of 4 individual socket comfort survey items. Socket comfort items were included in a self-report paper survey, which was administered to participants 2 to 3 days apart.

SETTING

General community.

PARTICIPANTS

A minimum convenience sample of participants (N=63) was targeted for this study; 72 lower limb prosthesis users (>1y postamputation) completed the survey and were included in the final dataset.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The expanded socket comfort score (ESCS) was adapted from the original socket comfort score (SCS). The original SCS is a single-item self-report instrument developed to assess a lower limb prosthesis user's current socket comfort. Three additional items were designed to assess the user's best, worst, and average socket comfort over the previous 7 days.

RESULTS

Best, worst, and average socket comfort items demonstrated better reliability, as indicated by higher intraclass correlation coefficients. As such, these items also exhibited lower measurement error and smaller minimal detectable change values than the item that measured current socket comfort. However, test-retest coefficients for all 4 ESCS items were below the level desired for evaluation of within-individual changes of socket comfort.

CONCLUSIONS

Items that assess best, worst, and average comfort provide a more stable measurement of socket fit than the existing SCS instrument. Although administration of all 4 ESCS items may provide more comprehensive assessment of a lower limb prosthesis user's socket fit, administrators should expect variations in scores over time owing to the variable nature of the underlying construct over time. Future research should examine whether the ESCS provides an improved overall assessment of socket fit.

Does socket liner material affect clinical outcomes in lower limb prosthesis users? Insights from a randomized control trial

Among the noted disadvantages of prosthesis suspension by flexible liner is the increased rate of perspiration within the socket, which has the potential to cause discomfort, suspension issues, and tissue damage. In recent years, phase change material technology has been adopted for the use in prosthesis liners. These promise to improve temperature control and, consequently, reduce sweating. Previous work has demonstrated that this approach is effective in slowing the temperature increase at the limb-socket interface, but it was not clear how this would translate to clinical outcomes. This study had the aim to compare conventional and phase change material liners regarding prosthesis utilization, physical performance, and patient-reported outcome measures. A randomized double-blind cross-over study design with 6-month intervention periods was used. Of the 42 enrolled participants, only 50% completed the protocol. The high attrition was in large part because of the COVID-19 pandemic that started disrupting daily life and thereby the data collection midway through the study period. The findings indicate that the temperature control liners were, by trend, associated with better prosthesis utilization. The found effects did not reach the level of statistical significance, which is likely a result of the unduly reduced sample size.

A review on magnetic and spintronic neurostimulation: challenges and prospects

In the treatment of neurodegenerative, sensory and cardiovascular diseases, electrical probes and arrays have shown quite a promising success rate. However, despite the outstanding clinical outcomes, their operation is significantly hindered by non-selective control of electric fields. A promising alternative is micromagnetic stimulation (μMS) due to the high permeability of magnetic field through biological tissues. The induced electric field from the time-varying magnetic field generated by magnetic neurostimulators is used to remotely stimulate neighboring neurons. Due to the spatial asymmetry of the induced electric field, high spatial selectivity of neurostimulation has been realized. Herein, some popular choices of magnetic neurostimulators such as microcoils (μcoils) and spintronic nanodevices are reviewed. The neurostimulator features such as power consumption and resolution (aiming at cellular level) are discussed. In addition, the chronic stability and biocompatibility of these implantable neurostimulator are commented in favor of further translation to clinical settings. Furthermore, magnetic nanoparticles (MNPs), as another invaluable neurostimulation material, has emerged in recent years. Thus, in this review we have also included MNPs as a remote neurostimulation solution that overcomes physical limitations of invasive implants. Overall, this review provides peers with the recent development of ultra-low power, cellular-level, spatially selective magnetic neurostimulators of dimensions within micro- to nano-range for treating chronic neurological disorders. At the end of this review, some potential applications of next generation neuro-devices have also been discussed.

Japanese translation and linguistic validation of the Prosthetic Limb Users Survey of Mobility (PLUS-M)

BACKGROUND

Self-report survey instruments can be used to improve clinical care for lower-limb prosthesis users on a global scale by pooling comparable health outcomes data from multiple countries. The language translation process is critical to the quality and comparability of a translated survey instrument.

OBJECTIVES

The goals of this research were to translate the Prosthetic Limb Users Survey of Mobility (PLUS-M) item bank from English to Japanese using established guidelines, and linguistically validate the translated instrument by assessing its clarity, comprehension, and cultural applicability with Japanese prosthesis users.

STUDY DESIGN

Instrument translation and qualitative interviews.

METHODS

The translation process included two forward translations, reconciliation, backward translation, and review by clinical experts in Japan. Adult lower-limb prosthesis users participated in a linguistic validation study by responding to translated survey items and providing item-by-item feedback through cognitive interviews.

RESULTS

Following expert reviews, translated items were classified as grammatically and contextually unchanged (n = 21), minor revision required (n = 19), major revision required (n = 3), or removed (n = 1). Cognitive interviews with 10 participants indicated that additional revisions were required (n = 4). Items were revised and retested until it was determined that they were clear, well understood, and culturally applicable.

CONCLUSIONS

Use of a multistep translation and linguistic validation processes resulted in a linguistically comparable Japanese translation of the PLUS-M item bank. Japanese translations of the PLUS-M 7- and 12-item short forms were created for use in clinical practice and research. Availability of these linguistically comparable instruments is expected to facilitate opportunities for international comparison of prosthetic mobility data.

Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Instruments Compare Favorably With Legacy Patient-Reported Outcome Measures in Upper- and Lower-Extremity Orthopaedic Patients: A Systematic Review of the Literature

PURPOSE

To compare Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) with traditional ("legacy") patient-reported outcome measures (PROMs) in regard to correlations, ease of use, and quality criteria for upper (UE) and lower extremity (LE) orthopaedic conditions.

METHODS

A systematic search of the PubMed/MEDLINE database was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify published articles that referenced the various PROMIS PF measures. Two authors independently reviewed selected studies. The search returned 857 studies, 85 of which were selected for independent review by 2 authors. Of these, 54 were selected for inclusion. Mixed linear models were performed to assess for differences between legacy PROMs and PROMIS measures.

RESULTS

The combined sample size of all included studies yielded 6,074 UE and 9,366 LE patients. Overall, PROMIS PF measures demonstrated strong correlations with legacy PROMs among UE (weighted Pearson correlation, 0.624, standard error [SE] = 0.042; weighted Spearman correlation, 0.566, SE = 0.042) and LE patients (weighted Pearson correlation, 0.645, SE = 0.062; weighted Spearman correlation, 0.631, SE = 0.041). PROMIS PF questionnaires completed by UE patients had fewer questions than legacy PROMs (5.9 vs 17.7, P = .0093) and were completed in less time (90.5 vs 223.8 seconds, P = .084). PROMIS PF questionnaires completed by LE patients had fewer questions than legacy PROMs (4.81 vs 15.33, P < .001) and were completed in less time (63.6 vs 203.2 seconds, P = .0063). The differences for the reliability measures were not significant.

CONCLUSIONS

PROMIS PF scores correlate strongly with commonly used legacy PROMs in orthopaedics, particularly in UE and LE patients. PROMIS PF forms can be administered efficiently and to a broad patient population while remaining highly reliable. Therefore, they can be justified for standardized use among orthopaedic patients with UE and LE conditions, improving the ability to aggregate and compare outcomes in orthopaedic research.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV evidence.

Recalled Number of Falls in the Past Year-Combined With Perceived Mobility-Predicts the Incidence of Future Falls in Unilateral Lower Limb Prosthesis Users

OBJECTIVE

Falls are a frequent and costly concern for lower limb prosthesis (LLP) users. At present, there are no models that clinicians can use to predict the incidence of future falls in LLP users. Assessing who is at risk for falls, therefore, remains a challenge. The purpose of this study was to test whether easily accessible clinical attributes and measurements predict the incidence of future falls in LLP users.

METHODS

In this prospective observational study, a secondary analysis of data from 60 LLP users was conducted. LLP users reported the number of falls that they recalled over the past year before prospectively reporting falls over a 6-month observation period via monthly telephone calls. Additional candidate predictor variables were recorded at baseline. Negative binomial regression was used to develop a model intended to predict the incidence of future falls.

RESULTS

The final model, which included the number of recalled falls (incidence rate ratio = 1.13; 95% CI = 1.01 to 1.28) and Prosthetic Limb Users Survey of Mobility T-scores (incidence rate ratio = 0.949; 95% CI = 0.90 to 1.01), was significantly better than a null model at predicting the number of falls over the next 6 months (χ22 = 9.76) and fit the observed prospective fall count data (χ256 = 54.78).

CONCLUSION

The number of recalled falls and Prosthetic Limb Users Survey of Mobility T-scores predicted the incidence of falls over the next 6 months in established, unilateral LLP users. The success and simplicity of the final model suggests that it may serve as a screening tool for clinicians to use for assessing risk of falls. Additional research to validate the proposed model in an independent sample of LLP users is needed.

IMPACT

Owing to its simplicity, the final model may serve as a suitable screening measure for clinicians to ascertain an initial evaluation of fall risk in established unilateral LLP users. Analyzing falls data as counts rather than as a categorical variable may be an important methodological consideration for falls prevention research.

Free-Living User Perspectives on Musculoskeletal Pain and Patient-Reported Mobility With Passive and Powered Prosthetic Ankle-Foot Components: A Pragmatic, Exploratory Cross-Sectional Study

Introduction

Studies with a powered prosthetic ankle-foot (PwrAF) found a reduction in sound knee loading compared to passive feet. Therefore, the aim of the present study was to determine whether anecdotal reports on reduced musculoskeletal pain and improved patient-reported mobility were isolated occurrences or reflect a common experience in PwrAF users.

Methods

Two hundred and fifty individuals with transtibial amputation (TTA) who had been fitted a PwrAF in the past were invited to an online survey on average sound knee, amputated side knee, and low-back pain assessed with numerical pain rating scales (NPRS), the PROMIS Pain Interference scale, and the PLUS-M for patient-reported mobility in the free-living environment. Subjects rated their current foot and recalled the ratings for their previous foot. Recalled scores were adjusted for recall bias by clinically meaningful amounts following published recommendations. Statistical comparisons were performed using Wilcoxon's signed rank test.

Results

Forty-six subjects, all male, with unilateral TTA provided data suitable for analysis. Eighteen individuals (39%) were current PwrAF users, whereas 28 subjects (61%) had reverted to a passive foot. After adjustment for recall bias, current PwrAF users reported significantly less sound knee pain than they recalled for use of a passive foot (−0.5 NPRS, p = 0.036). Current PwrAF users who recalled sound knee pain ≥4 NPRS with a passive foot reported significant and clinically meaningful improvements in sound knee pain (−2.5 NPRS, p = 0.038) and amputated side knee pain (−3 NPRS, p = 0.042). Current PwrAF users also reported significant and clinically meaningful improvements in patient-reported mobility (+4.6 points PLUS-M, p = 0.016). Individuals who had abandoned the PwrAF did not recall any differences between the feet.

Discussion

Current PwrAF users reported significant and clinically meaningful improvements in patient-reported prosthetic mobility as well as sound knee and amputated side knee pain compared to recalled mobility and pain with passive feet used previously. However, a substantial proportion of individuals who had been fitted such a foot in the past did not recall improvements and had reverted to passive feet. The identification of individuals with unilateral TTA who are likely to benefit from a PwrAF remains a clinical challenge and requires further research.

Microprocessor feet improve prosthetic mobility and physical function relative to non-microprocessor feet

Introduction: The clinical benefits associated with the microprocessor regulation of prosthetic ankle position and resistance have largely been reported through manufacturer conducted research in controlled laboratory environments. Measures with greater ecological validity are needed. This study aimed to understand if there are differences in physical function and mobility outcomes as patients transitioned from a non-Microprocessor to Microprocessor Feet. Method: A retrospective analysis of patient outcomes was performed. Patient-reported benefits associated with the adoption of such prosthetic foot-ankle mechanisms were collected from 23 individuals through the longitudinal use of a custom short form of the Patient-Reported Outcomes Measurement Information System-Physical Function and individual items from the Prosthesis Evaluation Questionnaire. Results: The impact of Microprocessor Feet upon physical function and mobility were observed in a significant increase in physical function (mean increase in t-score of 5.4 ± 1.25; p = .0004) and significant improvements in several mobility items. Conclusions: Collectively, these measures support the beneficial impact of Microprocessor Feet on improving socket comfort, reducing back pain, improving sit to stand transfers and enhancing hill ascent and descent as well as stair negotiation.

OASIS 2: Mobility differences with specific prosthetic feet across procedure codes

Introduction

Recently, many prosthetic devices were subjected to reimbursement coding review. Several prosthetic feet that were historically coded with the shock-attenuating function were recoded. The purpose of this analysis was to compare patient-reported functional mobility across a range of prosthetic feet using real-world clinical outcomes data.

Methods

A retrospective, observational review. A univariate generalized linear model was used to assess mobility across foot categories and between different prosthetic feet coded as L5987 or L5981.

Results

The final sample analyzed comprised of 526 individuals and four mutually exclusive categories of feet examined across a total of 10 different prosthetic foot types. The comparison of prosthetic foot categories were significantly different from the control category (i.e. historically L5981).

Conclusions

The current data suggest the development of some prosthetic foot designs using advanced materials and geometric designs can provide comparable functional benefits as those with distinct shock absorbing mechanical features. Emphasizing functional performance over visible features may be a pathway towards higher performance for the end user.

Functional outcomes and user preferences of individuals with transfemoral amputations using two types of knee joints in under-resourced settings

BACKGROUND

Information relating to prosthetic performance can inform clinical practice and improve patient outcomes in under-resourced countries.

OBJECTIVES

The main goal of this study was to compare functional outcomes and user preferences of individuals with transfemoral amputations using common types of knee joints in an under-resourced country.

STUDY DESIGN

Prospective, longitudinal, before and after trial.

METHODS

Twenty individuals with unilateral transfemoral amputations from a center in Cambodia transitioned from a commonly used single-axis manually locking knee International Committee of the Red Cross (ICRC) to a more advanced multiaxis knee joint with stance control All-Terrain Knee (ATK). Data were collected for the ICRC knee joint and the ATK immediately after fitting, after acclimation, and as part of a long-term follow-up. A timed walk test assessed walking distance and efficiency. Mobility and user-preferences were evaluated through questionnaires.

RESULTS

Distance during the timed walk test was significantly higher for the ATK compared with ICRC (P < 0.001), with functional gains retained at follow-up. No differences were found for gait efficiency and the mobility questionnaires. All participants, except one, preferred the ATK prosthesis. Benefits included greater knee stability and fewer perceived knee collapses; however, some disliked the appearance of the ATK.

CONCLUSIONS

The findings suggest positive outcomes with prosthetic services in under-resourced regions and the ICRC system, as well as the potential for improved functional outcomes with more advanced multiaxis knee components.

Content comparison of four commonly used amputee mobility assessment scales in the literature by linking to the International Classification of Functioning, Disability, and Health

BACKGROUND

Despite the fact that there are a number of studies revealing the linkage of scales with the World Health Organization's international classification of functioning, disability, and health (ICF), there is a need for comprehensive studies examining the relationship between amputee mobility scales and ICF.

OBJECTIVE

To analyze the content of four amputee mobility scales at the item level using the ICF.

METHODS

The Locomotor Capacity Index, Rivermead Mobility Index, Amputee Mobility Predictor, and Prosthetic Limb Users Survey of Mobility were analyzed by two health professionals for content comparison according to the ICF categories. Kappa statistic was used to calculate the degree of agreement between the two investigators.

RESULTS

A total of 62 items in the scales were analyzed and linked with ICF codes. The scale questions were linked with 27 different ICF codes as follows: 1 (3.7%) "body function", 23 (85.1%) "activity and participation", 2 (7.5%) "environmental factors," and 1 (3.7%) "not definable. The estimated kappa values ranged from 0.83 to 0.90 for ICF codes.

CONCLUSION

As a result of the study, the ICF is a highly effective resource that can be used in the analysis of amputee mobility scales. Because the scale items are more concentrated on the mobility chapter, it was seen that the scales generally served their purposes. In the light of the findings obtained, it is thought that the diversity of the scales in the concept distribution will guide clinicians and researchers in choosing scales according to their target 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.

Validade de construto do teste de caminhada de 2 minutos para pacientes com amputação de membro inferior protetizados

RESUMO Aliados da avaliação funcional, os testes de caminhada têm sido considerados confiáveis e válidos para várias populações, quantificando a capacidade funcional do indivíduo e respondendo a mudanças durante o processo de reabilitação. O objetivo deste artigo foi analisar a validade de construto do teste de caminhada de 2 minutos para pacientes com amputação de membro inferior protetizados, submetidos à reabilitação. Foi aplicado o teste de caminhada de 2 minutos em 51 pacientes maiores de 18 anos com diagnóstico clínico de amputação de membro inferior em qualquer nível e que tivessem sido submetidos à reabilitação há pelo menos seis meses no momento da avaliação, que foi correlacionada com os questionários Medida Funcional para Amputados (MFA) e os aspectos do Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), a fim de obter o coeficiente de correlação de Pearson com o nível de significância de p<0,05. Entre os participantes do estudo, 64,7% eram do sexo masculino, com média de idade de 53,4 anos; 59,92% tinham amputação de nível transtibial e a principal causa foi trauma, com 54,9%. O escore médio para os questionários foi de 63,58 pontos para a capacidade física do SF-36, e 37,14 pontos para a segunda questão do MFA. A correlação da distância percorrida no teste de caminhada de 2 minutos mostrou moderada correlação com a capacidade física do SF-36 e com a segunda questão do MFA. Os achados mostram moderada correlação entre o teste de caminhada de 2 minutos e as ferramentas subjetivas de avaliação de função utilizadas, mostrando que é um instrumento válido como medida objetiva para a população estudada.

Patient-reported benefits of bone-anchored transfemoral prostheses as assessed by MedTech20: A general outcome measure for medical products

BACKGROUND

The medical community demands evidence for the benefits of medical devices such as bone-anchored prostheses (BAPs). MedTech20  is a novel instrument aiming to address general benefits of medical devices.

OBJECTIVE

To describe general patient-reported benefits of BAPs measured with MedTech20.

STUDY DESIGN

This is a cross-sectional descriptive survey.

METHODS

Patients treated in Sweden who had used a BAP for >1 year were mailed the MedTech20  Questionnaire. Responses to each attribute were described, and the MedTech20   Index (0-1), in which a higher figure represents larger benefits from the product, was calculated. Index values were compared based on demographic variables (sex, unilateral or bilateral transfemoral amputation (TFA), and those having experienced any complication of implant parts or the prosthetic connection device).

RESULTS

The response rate was 72%. The 62 participants (41 men and 21 women; mean age 57 years) had 11 ± 6.9 mean years of BAP experience. Single attributes stated as highly relevant and with high benefit for BAPs included perceived reliability, perceived safety, sense of control of the disability, facilitation of movement outside home, no discomfort at use, and ease of use. Attributes with less relevance included aid to remember tasks, reduction of barriers to a good sleep, and reduced sense of compromised integrity. The MedTech20  Index was 0.655 ± 0.188 and was not statistically significantly different based on any of the demographic variables.

CONCLUSIONS

By using a general measure on attributes of medical devices, this study provides new insights strengthening the evidence regarding the benefits that BAPs provide for patients with TFA who had difficulties with socket-suspended prostheses.

Effects of a Prosthetic Foot With Increased Coronal Adaptability on Cross-Slope Walking

BACKGROUND

Walking on cross-slopes is a common but challenging task for persons with lower limb amputation. The uneven ground and the resulting functional leg length discrepancy in this situation requires adaptability of both user and prosthesis.

OBJECTIVES

This study investigated the effects of a novel prosthetic foot that offers adaptability on cross-slope surfaces, using instrumented gait analysis and patient-reported outcomes. Moreover, the results were compared with two common prosthetic feet.

METHODOLOGY

Twelve individuals with unilateral transtibial amputation and ten able-bodied control subjects participated in this randomized cross-over study. Participants walked on level ground and ±10° inclined cross-slopes at a self-selected walking speed. There were three prosthetic foot interventions: Triton Side Flex (TSF), Triton LP and Pro-Flex LP. The accommodation time for each foot was at least 4 weeks. The main outcome measures were as follows: frontal plane adaptation of shoe and prosthetic foot keel, mediolateral course of the center of pressure, ground reaction force in vertical and mediolateral direction, external knee adduction moment, gait speed, stance phase duration, step length and step width. Patient-reported outcomes assessed were the Activities specific Balanced Confidence (ABC) Scale, Prosthetic Limb Users Survey of Mobility (PLUS M) and Activities of Daily Living Questionnaire (ADL-Q).

FINDINGS

The TSF prosthetic foot adapted both faster and to a greater extent to the cross-slope conditions compared to the Triton LP and Pro-Flex LP. The graphs for the mediolateral center of pressure course and mediolateral ground reaction force showed a distinct grouping for level ground and ±10° cross-slopes, similar to control subjects. In the ADL-Q, participants reported a higher level of perceived safety and comfort when using the TSF on cross-slopes. Eight out of twelve participants preferred the TSF over the reference.

CONCLUSIONS

The frontal plane adaptation characteristics of the TSF prosthetic foot appear to be beneficial to the user and thus may enhance locomotion on uneven ground - specifically on cross-slopes.

Clinical Outcome of Transfemoral Direct Socket Interface (Part 2)

BACKGROUND

Amputation at the transfemoral (TF) level reduces the rate of successful prosthetic fitting, functional outcome, and quality of life (QoL) compared with transtibial amputation. The TF socket interface is considered the most critical part of the prosthesis, but socket discomfort is still the most common user complaint. Direct Socket for transfemoral prosthesis users is a novel interface fabrication process where the socket is shaped and laminated directly on the residual limb and delivered in a single visit.

OBJECTIVES

The aim of this study was to investigate if prosthetic users' quality of life (QoL), comfort, and mobility with a Direct Socket TF interface were comparable to their experience with their previous prostheses.

METHODOLOGY

The pre/post design prospective cohort study included 47 subjects. From this cohort, 36 subjects completed the 6-months follow-up (mean age 58 years, 27 males). Outcomes at baseline included EQ-5D-5L®, PLUS-M™, CLASS, ABC, AMPPRO, and TUG. At 6-weeks and 6-months, subjects repeated all measures. Seven Certified Prosthetist (CP) investigators performed observations and data collection at six different sites (from July 2018 to April 2020).

FINDINGS

Results showed significant improvement in all outcome measures for the 36 subjects that completed both 6-weeks and 6-months follow-ups. CLASS sub-scales showed significantly improved stability, suspension, comfort, and socket appearance. Improvement in K-Level and less use of assistive devices were observed with the AMPPRO instrument, indicating improved user mobility and performance. QoL was also increased, as measured in Quality-Adjusted-Life-Years (QALY) from the EQ-5D-5L.

CONCLUSIONS

Evidence from the findings demonstrate that the Direct Socket TF system and procedure can be a good alternative to the traditional method of prosthetic interface delivery.

Mapping of electrodermal activity (EDA) during outdoor community-level mobility tasks in individuals with lower-limb amputation

Introduction

Balance confidence and perception of task challenge is an important construct to measure in rehabilitation of people with lower-limb amputation (LLA). Measurement of electrodermal activity (EDA) captures physiological arousal responses reflecting an individual’s perceived challenge in a task. This study explores the feasibility of the use of EDA during outdoor walking tasks to capture task-specific physiological arousal changes associated with perception of challenge in people with amputation.

Objective

To develop and demonstrate feasibility of a portable EDA/GPS system mapping physiological arousal while challenging walking balance outdoors in individuals with LLA and controls.

Methods

Sixteen people (eight with LLA and eight age-/sex-matched controls) completed an outdoor walking course in the community (3 laps). A battery-powered portable device was developed containing EDA/GPS sensors with data logged on a microcontroller. Phasic EDA response was extracted from EDA signal to explore the physiological arousal response to walking tasks.

Results

Physiological arousal demonstrated task-specific modulation with ascending stairs without a handrail showing higher levels of phasic EDA than walking on a paved incline (p = 0.01) or a gravel decline (p = 0.01) in people with LLA. While evidence of habituation over repeated trials was shown in controls with lap 1 of walking down a gravel decline showing higher levels of phasic EDA than lap 3 (p = 0.01). Phasic EDA maps, representative of arousal levels throughout the walking course, showed individual-specific response.

Conclusion

Mapping of EDA during outdoor walking is feasible. Modulation of physiological arousal between outdoor walking tasks and over repeated trials is suggestive of clinical utility. Further research is warranted to explore how EDA may be incorporated into assessment of response to outdoor walking amongst individuals following LLA.

Comparison of patient-reported and functional outcomes following transition from mechanical to microprocessor knee in the low-activity user with a unilateral transfemoral amputation

BACKGROUND

The Scottish Specialist Prosthetics Service has provided microprocessor knees (MPKs) through the National Health Service since 2014, predominantly to high-activity transfemoral amputations (TFAs). Benefits of MPKs to the lower-activity TFA are less established in the literature.

OBJECTIVES

This study aimed to compare patient-reported and functional measures in low-activity TFAs transitioning from a mechanical knee to a MPK.

STUDY DESIGN

This is a retrospective cohort analysis of low-activity individuals with a unilateral TFA provided with an MPK.

METHODS

Patient-reported measures were recorded in routine clinical care before and 6 months after MPK provision. These included HR-QoL (EQ-5D-5L Health Index), Activities Balance Confidence score, Prosthetic Limb User Survey of Mobility, falls frequency, use of walking aids, and Socket Comfort Score. Functional measures included the two-minute walk test (2MWT), L-test, and Amputee Mobility Predictor score, and three-dimensional gait analysis was used to generate a Gait Profile Score (GPS). The primary outcomes were HR-QoL and GPS.

RESULTS

Forty-five participants fulfilled the inclusion criteria. Thirty-one had pre-MPK and post-MPK measures, of which 15 had three-dimensional gait analysis. The mean age (n = 31) was 60 years (SD 11), and 68% were male. HR-QoL and GPS did not significantly improve with MPK provision (p = 0.014 and p = 0.019); Amputee Mobility Predictor score, L-Test, 2MWT, falls, and Activities Balance Confidence score showed a significant improvement with MPK provision (p < 0.001).

CONCLUSIONS

Although no statistically significant change in the primary outcomes was measured, there were sufficient data to support MPK provision in low-activity prosthetic users with participants demonstrating improvements in balance, 2MWT, falls frequency, and confidence.

Self-reported socket comfort, mobility, and balance-confidence of individuals with transtibial amputation using pinlock vs suction suspension

BACKGROUND

Improper suspension between the residual limb and prosthesis can result in pistoning, which may compromise skin integrity and reduce overall user comfort. In addition to objective measures of limb pistoning, user perspective may provide insight into suspension system effectiveness.

OBJECTIVES

The primary objective of this analysis was to explore differences in self-reported measures among adults with transtibial amputation (TTA) using pinlock vs suction suspension systems.

STUDY DESIGN

This is a secondary analysis of cross-sectional data.

METHODS

Participants (n = 48) were included if they (1) were ≥18 years of age, (2) were community-dwelling, (3) had a unilateral TTA of ≥6 months, and (4) were prescribed a prosthesis with either pinlock or suction suspension. Participants completed self-reported measures evaluating socket comfort (Socket Comfort Score [SCS]), prosthesis-enabled mobility (Prosthesis Evaluation Questionnaire-Mobility Section [PEQ-MS]; Locomotor Capabilities Index [LCI]), and balance-confidence (Activities-Specific Balance Confidence Scale [ABC]).

RESULTS

Participants using suction suspension reported significantly higher SCS as compared with participants using pinlock suspension (P ≤ .001). No differences were observed between groups for PEQ-MS, LCI, and/or ABC.

CONCLUSIONS

Individuals with TTA using suction suspension may report greater socket comfort than peers using pinlock suspension, but prosthesis-enabled mobility and balance-confidence may be similar. Future research is warranted to confirm these preliminary findings using a prospective, crossover study design that controls for all suspected factors that might influence socket comfort.

Development of a physical mobility prediction model to guide prosthetic rehabilitation

BACKGROUND

Prosthetic rehabilitation decisions depend on estimating a patient's mobility potential. However, no validated prediction models of mobility outcomes exist for people with lower-limb amputation (LLA).

OBJECTIVES

To develop and test predictions for self-reported mobility after LLA, using the Prosthetic Limb Users Survey of Mobility (PLUS-M).

STUDY DESIGN

This is a retrospective cohort analysis.

METHODS

Eight hundred thirty-one patient records (1,860 PLUS-M observations) were used to develop and test a neighbors-based prediction model, using previous patient data to predict the 6-month PLUS-M T-score trajectory for a new patient (based on matching characteristics). The prediction model was developed in a training data set (n = 552 patients) and tested in an out-of-sample data set of 279 patients with later visit dates. Prediction performance was assessed using bias, coverage, and precision. Prediction calibration was also assessed.

RESULTS

The average prediction bias for the model was 0.01 SDs, average coverage was 0.498 (ideal proportion within the 50% prediction interval = 0.5), and prediction interval was 8.4 PLUS-M T-score points (40% improvement over population-level estimates). Predictions were well calibrated, with the median predicted scores falling within the standard error of the median of observed scores, across all deciles of the data.

CONCLUSIONS

This neighbors-based prediction approach allows for accurate estimates of PLUS-M T-score trajectories for people with LLA.

Performance-based balance tests, combined with the number of falls recalled in the past year, predicts the incidence of future falls in established unilateral transtibial prosthesis users

BACKGROUND

Falls are common and consequential events for lower limb prosthesis (LLP) users. Currently, there are no models based on prospective falls data that clinicians can use to predict the incidence of future falls in LLP users. Assessing who is at risk for falls, and thus most likely to need and benefit from intervention, remains a challenge.

OBJECTIVE

To determine whether select performance-based balance tests predict future falls in established, unilateral transtibial prosthesis users (TTPU).

DESIGN

Multisite prospective observational study.

SETTING

Research laboratory and prosthetics clinic.

PARTICIPANTS

Forty-five established, unilateral TTPU.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

The number of falls reported over a prospective 6-month period. Timed Up-and-Go (TUG) and Four-Square Step Test (FSST) times, as well as Narrowing Beam Walking Test scores were recorded at baseline, along with the number of falls recalled over the past 12 months and additional potential fall-risk factors.

RESULTS

The final negative binomial regression model, which included TUG (P = .044) and FSST (P = .159) times, as well as the number of recalled falls (P = .009), was significantly better than a null model at predicting the number of falls over the next 6 months (X² [3] = 11.6, P = .009) and fit the observed fall count data (X² [41] = 36.12, P = .20). The final model provided a significant improvement in fit to the prospective fall count data over a model with fall recall alone X² (1) = 4.342, P < .05.

CONCLUSION

No combination of performance-based balance tests alone predicted the incidence of future falls in our sample of established, unilateral TTPU. Rather, a combination of the number of falls recalled over the past 12 months, along with TUG and FSST times, but not NBWT scores, was required to predict the number of "all-cause" falls over the next 6 months. The resulting predictive model may serve as a suitable method for clinicians to predict the incidence of falls in established, unilateral TTPU.

Complications, mobility, and quality of life in ankle sarcoma patients

AIMS

The aims of the study were to analyze differences in surgical and oncological outcomes, as well as quality of life (QoL) and function in patients with ankle sarcomas undergoing three forms of surgical treatment, minor or major limb salvage surgery (LSS), or amputation.

METHODS

A total of 69 patients with ankle sarcomas, treated between 1981 and 2017 at two tumour centres, were retrospectively reviewed (mean age at surgery: 46.3 years (SD 22.0); 31 females (45%)). Among these 69 patients 25 were analyzed prospectively (mean age at latest follow-up: 61.2 years (SD 20.7); 11 females (44%)), and assessed for mobility using the Prosthetic Limb Users Survey of Mobility (PLUS-M; for amputees only), the Toronto Extremity Salvage Score (TESS), and the University of California, Los Angeles (UCLA) Activity Score. Individual QoL was evaluated in these 25 patients using the five-level EuroQol five-dimension (EQ-5D-5L) and Fragebogen zur Lebenszufriedenheit/Questions on Life Satisfaction (FLZ).

RESULTS

Of the total number of patients in the study, 22 (32%) underwent minor LSS and 22 (32%) underwent major LSS; 25 underwent primary amputation (36%). Complications developed in 26 (38%) patients, and were more common in those with major or minor LSS in comparison to amputation (59% vs 36% vs 20%; p = 0.022). A time-dependent trend towards higher complication risk following any LSS was present (relative risk: 0.204; 95% confidence interval (CI) 0.026 to 1.614; p = 0.095). In the prospective cohort, mean TESS was higher following minor LSS in comparison to amputation (91.0 vs 67.3; p = 0.006), while there was no statistically significant difference between major LSS and amputation (81.6 vs 67.3; p = 0.099). There was no difference in mean UCLA (p = 0.334) between the three groups (p = 0.334). None of the items in FLZ or EQ-5D-5L were different between the three groups (all p > 0.05), except for FLZ item "self-relation", being lower in amputees.

CONCLUSION

Complications are common following LSS for ankle sarcomas. QoL is comparable between patients with LSS or amputation, despite better mobility scores for patients following minor LSS. We conclude that these results allow a decision for amputation to be made more easily in patients particularly where the principles of oncological surgery would otherwise be at risk. Cite this article: Bone Joint J 2021;103-B(3):553-561.

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

BACKGROUND

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

CLINICAL RELEVANCE

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

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

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

Mobility with a lower limb prosthesis: experiences of users with high levels of functional ability

PURPOSE

The Prosthetic Limb Users Survey of Mobility (PLUS-M) is a self-report item bank designed to measure the abilities with which people with lower limb amputation perform physical activities. Although PLUS-M includes items that span a range of mobility, additional items are needed to accurately measure mobility of highly active prosthesis users, such as athletes and service members with lower limb amputation. The aim of this study was to understand mobility in highly active lower limb prosthesis users to inform the development of new items for the PLUS-M item bank.

METHODS

Focus groups were conducted with active, lower limb prosthesis users from across the USA. In-person and online focus groups were conducted by a trained facilitator using a semi-structured guide. Focus group transcripts were reviewed and coded by two researchers. Thematic analysis was used to identify important experiences across participants.

RESULTS

Twenty-nine participants took part in four focus groups. Three resultant themes were identified: mobility after amputation, mobility characteristics, and healthcare providers and systems.

CONCLUSIONS

Identified themes inform clinician and researcher understanding of mobility in highly active lower limb prosthesis users. The results of this study will be used to inform development of high-activity items for the PLUS-M item bank.Implications for rehabilitationParticipants described engagement in high-level activities as a learning process that included elements such as equipment challenges and modifications, pain and injury, and the need to trust the prosthetic limb.Participants with lower limb amputation who use prostheses identified mobility characteristics, such as postural changes, terrain, and obstacles, that influenced their ability to perform high-level activities.High-level mobility characteristics identified in these focus groups can be integrated into a revised version of the Prosthetic Limb Users Survey of Mobility to assess mobility in active adults and athletes with amputation.Rehabilitation professionals play an important role in facilitating access to specialized prosthetic components and training that can help patients achieve their mobility goals and potential.

Characterizing Practice Effects in Performance-Based Tests Administered to Users of Unilateral Lower Limb Prostheses: A Preliminary Study

BACKGROUND

Performance-based tests are viewed as a gold standard for measuring physical capability. Practice effects, however, may threaten their predictive, discriminative, and evaluative applications. Despite these potential consequences, practice effects have received limited attention in users of lower limb prostheses (LLP).

OBJECTIVE

To perform an initial characterization of the occurrence, time-course, and magnitude of practice effects in three performance-based tests administered to users of LLP.

DESIGN

Secondary analysis of data from a multisite repeated-measures study.

SETTING

Outpatient clinic and research laboratory.

PARTICIPANTS

Convenience sample of established ambulatory users of unilateral transtibial and transfemoral prostheses (n = 60).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Practice effects were identified as significant changes in slope of participants' cumulative trial-by-trial records. The occurrence, time-course, and magnitude of practice effects were computed for the Timed Up and Go (TUG), Four Square Step Test (FSST), and the 10-m Walk Test (10mWT).

RESULTS

Across tests, practice effects were observed in 45% to 76% of participants. The proportion of participants with practice effects (ie, occurrence) was significantly greater for the FSST than the 10mWT (P = .008). The median number of trials (ie, time-course) required for participants to reach a consistent level of performance was not significantly different between tests (FSST: 4 trials, TUG: 4 trials; 10mWT: 3.5 trials; P = .481). Practice effect magnitude (ie, difference between the mean of trials during the plateau and best performance over the first two trials) was significantly greater than zero for the FSST (1.6 s; 16%) and TUG (1.4 s; 13%) (P < .05).

CONCLUSION

Results indicate that the FSST, TUG, and 10mWT were susceptible to practice effects in this sample of users of LLP. Practice effects may obscure significant differences in walking and balance ability, and thereby, in the absence of modifications, limit the use of these tests for making individual patient clinical decisions and analyzing group-level data.

Barriers and facilitators to work participation for persons with lower limb amputations in Bangladesh following prosthetic rehabilitation

BACKGROUND

Lower limb amputation due to workplace injury and motor vehicle accident is common in Bangladesh. Qualitative research may extend our understanding of how physical impairment and other factors, such as cultural norms, family roles and the built environment, facilitate or hinder work participation following lower limb amputation and prosthetic rehabilitation.

OBJECTIVES

The aim of this study was to explore the experience of people in Bangladesh following lower limb amputation and prosthetic rehabilitation to understand the facilitators and barriers to their work participation.

STUDY DESIGN

Qualitative interviews with thematic analysis.

METHODS

The Worker Role Interview was used to guide semi-structured interviews in a convenience sample of 10 adults living in Bangladesh following lower limb amputation and prosthetic rehabilitation. Interviews were interpreted, and the themes that emerged were evidenced with first-person quotes.

RESULTS

Barriers and facilitators to work participation were synthesised into the following themes: spirituality, attitudes, meaning of work, planning for work participation, traditional gender roles, social support, mobility aids, environmental challenges and ergonomic adaptations.

CONCLUSION

This qualitative approach identified barriers and facilitators to work participation, such as the role of spirituality and the effect of gender roles, that have not been well researched in this population. Being aware of their effects can help clinicians reduce barriers to work participation.

CLINICAL RELEVANCE

Greater awareness of the barriers and facilitators to work participation, such as the role of spirituality or the effect of gender roles, can assist clinicians to reduce barriers and help facilitate work participation for people living in Bangladesh following lower limb amputation and prosthetic rehabilitation.

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

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

The feasibility and validity of a wearable sensor system to assess the stability of high-functioning lower-limb prosthesis users

Introduction

Lower-limb prosthesis users (LLPUs) experience increased fall risk due to gait and balance impairments. Clinical outcome measures are useful for measuring balance impairment and fall risk screening but suffer from limited resolution and ceiling effects. Recent advances in wearable sensors that can measure different components of gait stability may address these limitations. This study assessed feasibility and construct validity of a wearable sensor system (APDM Mobility Lab) to measure postural control and gait stability.

Materials and Methods

Lower-limb prosthesis users (n=22) and able-bodied controls (n=24) completed an Instrumented Stand-and-Walk Test (ISAW) while wearing the wearable sensors. Known-groups analysis (prosthesis versus controls) and convergence analysis (Prosthetic Limb Users Survey of Mobility [PLUS-M] and Activity-specific Balance Confidence [ABC] Scale) were performed on 20 stability-related measures.

Results

The system was applied without complications; however missing anticipatory postural adjustment data points for nine subjects affected the analysis. Of the 20 analyzed measures output by the sensors, only three significantly differed (p≤.05) between cohorts, and two demonstrated statistically significant correlations with the self-report measures.

Conclusions

The results of this study suggest the clinical feasibility but only partial construct validity of the wearable sensor system in conjunction with the ISAW test to measure LLPU stability and balance. The sample consisted of high-functioning LLPUs, so further research should evaluate a more representative sample with additional outcome measures and tasks.

Selecting, Administering, and Interpreting Outcome Measures among Adults with Lower-Limb Loss: An Update for Clinicians

Purpose of review

To summarize outcome measurement research among adults with lower-limb loss (LLL) for clinicians.

Recent findings

Houghton Scale, Prosthetic Evaluation Questionnaire-mobility subscale (PEQ-m), Prosthetic Limb Users Survey of Mobility (PLUS-M™), Activities-Specific Balance Confidence Scale (ABC), Amputee Mobility Predictor (AMP), Comprehensive High-Level Activity Mobility Predictor, Four Square Step Test (FSST), Narrowing Beam Walking Test (NBWT), L Test, 10 Meter Walk Test (10MWT), and 6 Minute Walk Test (6MWT) are appropriate for evaluating individual patient changes post-LLL. Post-LLL, Socket Comfort Score, Patient-Specific Functional Scale, Patient-Reported Outcomes Measurement Information System 29-Item Profile, Timed Up and Go, and 2 Minute Walk Test may be more appropriate for evaluating groups. Minimal detectable change is available for 15/20 reviewed measures. Many measures differ between mobility levels.

Summary

Quick, reliable measures for evaluating patient functional change include ABC, PEQ-m, PLUS-M™, FSST, and L Test; when resources allow, NBWT, 10MWT, 6WMT and AMP may be considered.

The effect of participation in a mobility clinic on self-reported mobility and quality of life in people with lower limb amputation: A pilot study

BACKGROUND

Many people with lower limb amputation experience mobility impairment and reduced quality of life. Mobility clinics are designed to improve mobility and quality of life for people with lower limb amputation, but their effectiveness is unknown.

OBJECTIVES

To compare changes in mobility prior to, and 12 weeks following participation in mobility clinic for people with lower limb amputation, and to explain whether changes in mobility explained changes in quality of life. To determine whether the PLUS-M™ was sensitive to the effects of participation in the mobility clinic, and to estimate the sample size required for a definitive study.

STUDY DESIGN

Longitudinal observational.

METHODS

Electronic versions of the PLUS-M and SF-36v2^® were completed by people living in the community with lower limb amputation prior to, and 12 weeks following participation in a mobility clinic.

RESULTS

There was a significant increase in mobility from baseline to 12 weeks post participation in the clinic (p = 0.012). Changes in mobility explained a significant proportion of variance in the SF-36v2 mental component summary (p = 0.024) but not the physical component summary (p = 0.804).

CONCLUSION

For people with lower limb amputation, mobility increased after participation in the clinic and this explained improvements in SF-36v2 mental component summary. The PLUS-M was sensitive enough to detect a change in mobility over time.

CLINICAL RELEVANCE

This preliminary data indicated that participation in a mobility clinic improved mobility and the mental components of quality of life for people living with lower limb amputation. The PLUS-M™ seems sensitive to changes in mobility as a result of participation in a mobility clinic.

Interrater and Test-Retest Reliability of Performance-Based Clinical Tests Administered to Established Users of Lower Limb Prostheses

OBJECTIVE

A major barrier to reducing falls among users of lower limb prostheses (LLP) has been an absence of statistical indices required for clinicians to select and interpret scores from performance-based clinical tests. The study aimed to derive estimates of reliability, measurement error, and minimal detectable change values in performance-based clinical tests administered to unilateral LLP users.

METHODS

A total of 60 unilateral LLP users were administered the Narrowing Beam Walking Test, Timed ``Up and Go'' (TUG), Four Square Step Test (FSST), and 10-Meter Walk Test on 2 occasions, 3 to 9 days apart. Intraclass correlation coefficients (ICCs) were calculated to assess interrater and test-retest reliability, while standard error of measurement (SEM) and minimal detectable change (MDC90) were derived to establish estimates of measurement error in individual scores or changes in score for each test.

RESULTS

Interrater reliability ICCs (1,1) were high for all tests (ie, ≥0.98). Test-retest ICCs (2,1) varied by test, ranging from .88 for the TUG to .97 for the FSST. SEM and MDC90 varied between .39 and .96 and between .91 seconds and 2.2 seconds for the time-based tests (FSST, TUG, 10-Meter Walk Test). SEM and MDC90 for the Narrowing Beam Walking Test were .07 and .16, respectively.

CONCLUSION

With the exception of the TUG, studied tests had test-retest ICCs (2,1) that exceeded the minimum required threshold to be considered suitable for group- and individual-level applications (ie, ICC ≥ 0.70 and ≥ 0.90, respectively). Future research on individuals with dysvascular and transfemoral amputations or in specific age categories is required.

IMPACT

Along with published validity indices, these reliability, error, and change indices can help clinicians select balance tests suitable for LLP users. They can also help clinicians interpret test scores to make informed, evidence-based clinical decisions.

Evaluation Tools for Assistive Technologies: A Scoping Review

OBJECTIVE

Assistive technologies (ATs) support independence and well-being in people with cognitive, perceptual, and physical limitations. Given the increasing availability and diversity of ATs, evaluating the usefulness of current and emerging ATs is crucial for informed comparison. We aimed to chart the landscape and development of AT evaluation tools (ETs; ATETs) across disparate fields in order to improve the process of AT evaluation and development.

DATA SOURCES

We performed a scoping review of ATETs through database searching of MEDLINE, Embase, CINAHL, HaPI, PsycINFO, Cochrane Reviews, and Compendex as well as citation mining.

STUDY SELECTION

Articles explicitly referencing ATETs were retained for screening. We included ETs if they were designed to specifically evaluate ATs.

DATA EXTRACTION

We extracted 5 attributes of ATETs: AT category, construct evaluated, conceptual frameworks, type of end user input used for ATET development, and presence of validity testing.

DATA SYNTHESIS

From screening 23,434 records, we included 159 ATETs. Specificity of tools ranged from single to general ATs across 40 AT categories. Satisfaction, functional performance, and usage were the most common constructs of 103 identified. We identified 34 conceptual frameworks across 53 ETs. Finally, 36% incorporated end user input and 80% showed validation testing.

CONCLUSIONS

We characterized a wide range of AT categories with diverse approaches to their evaluation based on varied conceptual frameworks. Combining these frameworks in future ATETs may provide more holistic views of AT usefulness. ATET selection may be improved with guidelines for conceptually reconciling results of disparate ATETs. Future ATET development may benefit from more integrated approaches to end user engagement.

Effectiveness of an Evidence-Based Amputee Rehabilitation Program: A Pilot Randomized Controlled Trial

BACKGROUND

Despite the prevalence of lower limb amputation (LLA), only a small percentage of people with LLA actually receive physical therapy post amputation and are rehabilitated to their full potential level of function. There is a need for the development of a rehabilitation program that targets impairments and limitations specific to people with LLA.

OBJECTIVE

The objective of this study was to determine whether the Evidence-Based Amputee Rehabilitation program would improve functional mobility of people with unilateral transtibial amputation (TTA) who have already completed physical therapy and prosthetic training.

DESIGN

This study was a randomized, wait-list control, single-blinded pilot clinical trial.

SETTING

This study researched participants who had received postamputation rehabilitation to varying degrees, either in an inpatient and/or outpatient settings.

PARTICIPANTS

The participants in this study included veterans and nonveterans with unilateral TTA due to dysvascular disease and trauma.

INTERVENTION

This study included a prescription-based rehabilitation program for people with amputations.

MEASUREMENTS

Results were measured with The Amputee Mobility Predictor with (AMPPro) and without a prosthesis (AMPnoPro) and 6-Minute Walk Test (6MWT) at baseline and at the end of the 8-week intervention.

RESULTS

The intervention group improved on the AMPPro scores (36.4 to 41.7), AMPnoro scores (23.2 to 27.1), and 6MWT distance (313.6 to 387.7 m). The effect size for the intervention was very large (1.32). In contrast, the wait-list control group demonstrated no change in AMPPro scores (35.3 to 35.6), AMPnoPro scores (24.7 to 25.0), and 6MWT distance (262.6 m to 268.8 m).

LIMITATIONS

The sample size was small. A total 326 potential candidates were screened with 306 unable to meet inclusion criteria or unwilling to participate.

CONCLUSION

People with unilateral TTA who received Evidence-Based Amputee Rehabilitation program demonstrated significant improvement in functional mobility, with most participants (66.7%) improved at least 1 K-level (58.3%) and greater than the minimal detectable change (66.7%).

Increased prefrontal cortical activation during challenging walking conditions in persons with lower limb amputation - an fNIRS observational study

Background: Lower limb amputation (LLA) alters the sensorimotor control systems. Despite the self-reports of increased attention during mobility, the interaction between mobility and cognitive control mechanisms is not fully understood.Objective: Concurrently evaluate walking performance and prefrontal cortical (PFC) activity in persons with and without LLA during different walking conditions.Methods: Thirty-nine persons with LLA and thirty-three able-bodied controls participated. Walking performance was evaluated using the Figure-of 8-walk-test during three conditions: 1) UW (Usual walking with self-selected walking speed); 2) WCT (walking and carrying a tray with two cups filled with water); and 3) WUT (walking on uneven terrain). PFC activity was assessed using functional near-infrared spectroscopy (fNIRS). Linear mixed models were used to detect changes between groups and between walking conditions within each group.Results: Between-group comparisons showed increased PFC activity in persons with LLA during UW and WUT, and a significant decrease in walking performance during WCT and WUT compared to controls. Within-group comparisons showed increased PFC activity during WUT compared with UW and WCT and an overall difference in walking performance between the conditions (WU > WUT > WCT) in both groups. However, the effect of walking condition on PFC activity and walking performance was not modified by group (P > .1).Conclusion: The results suggest that persons with LLA have increased attentional demands during walking but choose the same cognitive-mobility strategy during challenging walking conditions as able-bodied persons. However, the attentional demands seem to depend on the complexity of the task.

Modifications of the pirogoff amputation technique in adults: A retrospective analysis of 123 cases

BACKGROUND

The Pirogoff amputation (1854) was initially developed to provide full-weight-bearing stumps and therefore allow a short ambulation without prosthesis. Modifications of the original technique including Boyd (1939) and the "Modified Pirogoff" were developed, which further reduced complications and improved the outcome. However, the current evidence regarding the techniques is scarce. The functional outcome, survivorship and complication rates are unknown. It was the purpose of this study to expand the knowledge with a retrospective case series and ultimately summarize and analyze the data with a systematic review.

METHODS

A retrospective study of the Boyd procedures from our institution between 1999 and 2018 was performed. Outcome was determined based on the PLUS-M Score (Prosthetic Limb Users Survey of Mobility). Survivorship (absence of more proximal amputation), postoperative leg-length discrepancy, time to early fusion and time to mobilization were also evaluated. Finally, in the second part of the study, the results were integrated in a systematic review, which followed the Preferred Reporting Items of Systematic Reviews and Meta-analysis (PRISMA) guidelines. The quality of all the studies were then assessed using the Joanna Briggs Institute Critical Appraisal Checklist (JBI CAC).

RESULTS

A total of 123 procedures including 115 patients, with an average follow-up of 45 months (range, 10-300 months) could be included. A very good or good function could be achieved in 85 (69%) patients. The mean survivorship was 82.1% (range 46%-100%). In four studies, including our series, all patients remained with a functional stump at the latest follow-up. The calculated average leg-length discrepancy was 2.5 cm.

CONCLUSION

The "Modified Pirogoff" and Boyd amputation techniques can achieve favourable long-term functional outcome in cases of irreparable foot conditions such as osteomyelitis or trauma. Patency of the posterior tibial artery is an indispensable condition to elect for these surgical techniques. Presence of neuropathy does not preclude this amputation level. With proper patient selection, a maximal survivorship of the stump with treatable minor complications can be achieved.Level of Evidence: IV.

Mobility Analysis of AmpuTees (MAAT 6): Mobility, Satisfaction, and Quality of Life among Long-Term Dysvascular/Diabetic Prosthesis Users-Results of a Cross-Sectional Analysis

Objective

The aim of this study was to establish the mobility, satisfaction, and quality of life (QoL) among prosthesis users with dysvascular/diabetic amputation at both acute and long-term phases of prosthetic rehabilitation.

Methods

This is a multisite, cross-sectional outcomes analysis. A total of 341 individuals met the inclusion/exclusion criteria. Individuals were grouped into acute phases (0–3 months [n = 24], 4–6 months [n = 72]) and chronic phases (24–36 months [n = 91], 37–48 months [n = 53], 49–60 months [n = 47], and 60–84 months [n = 54]) after amputation. Mobility was measured with the Prosthetic Limb Users Survey of Mobility (PLUS-M), whereas QoL and satisfaction (Sat) were reported using 10-point scales adapted from the Prosthesis Evaluation Questionnaire–Well-Being (PEQ-WB). Composite PEQ-WB scores were also compared.

Results

The average mobility, QoL, and Sat among prosthesis users was, respectively, 44.8 ± 10.6, 7.6 ± 2.2, and 7.6 ± 2.2. There were no observed differences in mobility (F_5,330 = 1.52, P = 0.18), QoL (F_5,333 = 0.78, P = 0.57), or PEQ-WB (F_5,335 = 1.618, P = 0.155) between any groups. For Sat, there was a group difference (F_5,334 = 2.44, P = 0.03) as individuals appear to experience an initial increase in Sat with receipt of a prosthesis (0–3 months) compared with 25 to 36 months (P = 0.005), 49 to 60 months (P = 0.008), and 61 to 84 months (P = 0.009).

Conclusions

Those individuals with amputation secondary to dysvascular disease and diabetes who continue to participate in prosthetic rehabilitation appear to experience levels of mobility, Sat, and QoL 7 years after amputation comparable to that reported in the first 6 months postamputation. There may be a modest increase in Sat with receipt of an initial prosthesis, potentially due to an increased optimism for one's situation. Notably, the mobility levels observed in the dysvascular population through a range of long-term postamputation periods remain within a single standard deviation of the population mean for individuals with a lower-limb amputation using a prosthesis for mobility.

The Effectiveness of the DoD/VA Mobile Device Outcomes-Based Rehabilitation Program for High Functioning Service Members and Veterans with Lower Limb Amputation

Introduction

The objective was to determine if the Mobile Device Outcomes-based Rehabilitation Program (MDORP) improved strength, mobility, and gait quality in service members (SMs) and Veterans with lower limb amputation (LLA).

Methods

Seven SMs and 10 Veterans with LLA enrolled and were trained to use a mobile sensor system, called Rehabilitative Lower Limb Orthopedic Analysis Device (ReLOAD). ReLOAD provided participants with real-time assessment of gait deviations, subsequent corrective audio feedback, and exercise prescription for normalizing gait at home and in the community. After baseline testing, prosthetic gait and exercise training, participants took ReLOAD home and completed an 8-week walking and home exercise program. Home visits were conducted every 2 weeks to review gait training and home exercises.

Results

Significant improvements in hip extensor strength, basic and high-level mobility, musculoskeletal endurance, and gait quality (P &lt; 0.05) were found at the completion of the 8-week intervention.

Conclusion

Preliminary MDORP results are promising in its ability to improve basic and high-level mobility, lower limb strength, and gait quality in a group of SMs and Veterans with LLA. In addition, “booster” prosthetic training may be justified in an effort helps maintain an active lifestyle, promotes prosthetic use, and mitigates secondary health effects.

Relevance of medical comorbidities for functional mobility in people with limb loss: retrospective explanatory models for a clinical walking measure and a patient-reported functional outcome

OBJECTIVES

Various modifiable and non-modifiable factors affect functional mobility, but subjective patient-reported and objective performance-based measures are rarely combined in explanatory analyses of functional mobility in people with limb loss. This study determined separate explanatory models for patient-reported function using the Prosthetic Evaluation Questionnaire Mobility Subscale (PEQ-MS), and performance-based 2-Minute Walk Test (2MWT).

DESIGN

Retrospective cross-sectional observational analysis.

SETTING

Wellness-walking program.

PARTICIPANTS

Three hundred five volunteers with lower limb loss participated. Sixty nine percent were men, mean age 56 (15) years. Fifty two percent had vascular amputation causes, 42% had surgical levels above the knee, and 82% had medical comorbidities. Walking levels included limited-household (21%), limited-community (30%), and independent-community (49%). Outcome measures included patient-reported PEQ-MS, Activities-specific Balance Confidence (ABC) and Houghton scales; and performance-based balance and walking.

MAIN OUTCOMES

Separate PEQ-MS and 2MWT multiple regression models fit using backward deletion.

RESULTS

Modifiable (balance ability, ABC, Houghton score; P<0.05) and non-modifiable factors (sex, amputation cause, surgical level; P<0.05) explained the variance in 2MWT (adjusted R²=0.685). Patient-reported and performance-based modifiable factors (Houghton score, 2MWT; P<0.001) explained PEQ-MS variance (adjusted R²=0.660). Integumentary (P=0.022) and cardiopulmonary (P<0.001) comorbidities explained an additional 4% of PEQ-MS variance, while surgical level was insignificant.

CONCLUSIONS

Both modifiable and non-modifiable factors explained prosthetic functional mobility. Performance-based walking was explained by modifiable factors including balance ability and confidence, prosthesis and walking aid use. Patient-reported function was also explained by prosthesis and walking aid use, walking speed and medical comorbidities. Modifiable factors for objective and subjective prosthetic mobility may provide a clinical roadmap for rehabilitation.

OASIS 1: Retrospective analysis of four different microprocessor knee types

INTRODUCTION

Microprocessor knee analyses to date have been primarily limited to microprocessor knees as a category rather than comparisons across different models. The purpose of the current analysis was to compare outcomes from four common knee models.

METHODS

A retrospective analysis of clinical outcomes was performed. Outcomes for functional mobility, quality of life, satisfaction with amputee status, and injurious falls were compared. Specific knee types represented were C-Leg (Ottobock), Orion (Blatchford), Plié (Freedom Innovations), and Rheo (Össur).

RESULTS

Outcomes from 602 individuals were included. No significant differences were noted for functional mobility (H = 2.91, p = 0.406) or satisfaction (H = 4.43, p = 0.219). For quality of life, differences existed for C-Leg versus Plié (p = 0.010). For injurious falls, C-Leg (χ2 (1,137) = 10.99, p < 0.001) and Orion (χ2 (1,119) = 4.34, p = 0.037) resulted in significantly reduced injurious falls compared to non-microprocessor knee users. C-Leg (H = 19.63, p < 0.001) and Plié (H = 14.04, p = 0.003) users saw declines with advanced aging.

CONCLUSIONS

Our data indicate relative parity among the 4 microprocessor knees with regard to functional mobility and satisfaction. In contrast to mobility, neither satisfaction nor quality of life values reflected declines with aging. Finally, when compared to non-microprocessor knees, significant differences were observed across the microprocessor knee types in relation to the reduction of injurious falls.Keywords: MPK, mobility, quality of life, falls, amputee, outcomes.

Patellar tendon morphology in trans-tibial amputees utilizing a prosthesis with a patellar-tendon-bearing feature

A patellar-tendon-bearing (PTB) bar is a common design feature used in the socket of trans-tibial prostheses to place load on the pressure-tolerant tissue. As the patellar tendon in the residual limb is subjected to the perpendicular compressive force not commonly experienced in normal tendons, it is possible for tendon degeneration to occur over time. The purpose of this study was to compare patellar tendon morphology and neovascularity between the residual and intact limbs in trans-tibial amputees and healthy controls. Fifteen unilateral trans-tibial amputees who utilized a prosthesis with a PTB feature and 15 age- and sex- matched controls participated. Sonography was performed at the proximal, mid-, and distal portions of each patellar tendon. One-way ANOVAs were conducted to compare thickness and collagen fiber organization and a chi-square analysis was used to compare the presence of neovascularity between the three tendon groups. Compared to healthy controls, both tendons in the amputees exhibited increased thickness at the mid- and distal portions and a higher degree of collagen fiber disorganization. Furthermore, neovascularity was more common in the tendon of the residual limb. Our results suggest that the use of a prosthesis with a PTB feature contributes to morphological changes in bilateral patellar tendons.