Mobility and satisfaction with a microprocessor-controlled knee in moderately active amputees: A multi-centric randomized crossover trial

Evaluation of activity and function before and immediately after the provision of a microprocessor knee in individuals with transfemoral amputation

BACKGROUND

In many cases, individuals with lower limb amputation become less active because of impaired balance and stability and increased risk of falling. Microprocessor knees (MPKs) have been shown to reduce the risk of falls, improve balance, and increase function, evaluated with self-reported scales and questionnaires. This study aims at investigating whether the patient-reported improvements are reflected in objective physical activity (PA) parameters estimated from actimetry sensors and assess the short-term provision of an MPK.

STUDY DESIGN

Transfemoral amputee patients (n=29) undertaking an MPK trial at 2 prosthetic centers in the South of England were recruited for this study. Self-reported and functional test outcomes (Activities Balance Confidence, Reintegration of Normal Living Index, Prosthesis Evaluation Questionnaire scores, and 2-min walk test) were obtained before and after (4 weeks) the provision of the MPK. Activity levels were recorded over 7 consecutive days pre- and post-MPK.

RESULTS

Self-reported scores and function test outcomes showed a general improvement in most of the patients after the provision of the MPK, with a statistically significant change (p < 0.05) in Activities Balance Confidence, Reintegration of Normal Living Index, Prosthesis Evaluation Questionnaire scores, and 2-min walk test. By contrast, the activity-based parameters estimated from actimetry showed no statistically significant changes (p > 0.05). Associations between self-reported and functional outcomes and actimetry parameters were limited.

CONCLUSIONS

Perceived and in-clinic outcome measures improved after short-term provision of an MPK for transfemoral amputees. However, PA did not change in this cohort of patients over the study period. More longitudinal studies are needed to characterize the impact of MPK provision on PA and societal participation.

The effects of microprocessor prosthetic knee use in early rehabilitation: A pilot randomized controlled trial

BACKGROUND

Microprocessor-controlled prosthetic knees (MPKs) improve safety, stability, and mobility for people with transfemoral amputation. Despite these benefits, MPKs are often not used for people in early rehabilitation.

OBJECTIVE

To assess the feasibility of a study that compares MPKs and nonmicroprocessor knees (NMPKs) for people with recent transfemoral amputation and report on health outcomes after 3 months of use. Investigators hypothesized that MPK users would have better outcomes than NMPK users.

DESIGN

Pilot randomized controlled study.

SETTING

Institutional laboratory.

PARTICIPANTS

Adults with recent unilateral transfemoral amputation, deemed ready for their first prosthesis, and weighed <125 kg. Eighteen participants enrolled; 15 completed the study.

INTERVENTIONS

Participants were randomized to use a MPK or NMPK in their first prosthesis.

MAIN OUTCOME MEASURE(S)

Feasibility outcomes included recruitment, retention, and missing data. Health outcome measures included performance-based and self-reported measures of mobility, participation, step activity, and falls.

RESULTS

Eighteen of 24 planned participants enrolled in the study. Fifteen participants received a study prosthesis and completed the 3-month trial (MPK: n = 9; NMPK: n = 6). Participants with an MPK had significantly higher Prosthetic Limb Users Survey of Mobility (p = .01, Hedges' g: 1.70), Activity-specific Balance Confidence (p = .01, Hedges' g: 1.75), and Return to Normal Living Index (p = .05, Hedges' g: 0.54) scores compared to patients with NMPK. No other outcomes significantly differed between groups; effect sizes (0.47-1.75) across mobility outcomes indicated better outcomes in the MPK group.

CONCLUSIONS

Enrollment goals were limited by the COVID-19 pandemic, but all 15 participants who received a study prosthesis finished the 3-month pilot study. The MPK group generally had better 3-month outcomes than the NMPK group, but few statistically significant differences were found due to the small sample size and heterogeneity within groups. Results from this pilot study can inform and power future studies that compare MPKs and NMPKs in early rehabilitation.

Retrospective cohort study of the economic value of providing microprocessor knees to the population of Medicare fee-for-service K2 beneficiaries with a knee disarticulation/above knee amputation

BACKGROUND

Microprocessor knees (MPKs) improve the functional mobility, quality of life, and safety of individuals with a knee disarticulation or above knee amputation and are cost-effective when adjusting for quality-of-life years gained. However, few studies have been conducted on the K2 population, and to this point, the Centers for Medicare and Medicaid Services has not covered MPKs for the K2 population.

OBJECTIVES

The aim of this study was to determine the extent to which MPK provision to the K2 population is cost effective at the person and population levels. A secondary objective was to determine the effectiveness of MPKs at reducing injurious falls within the K2 population.

STUDY DESIGN

A retrospective cohort study using Medicare fee-for-service claims data from the Centers for Medicare and Medicaid Services.

METHODS

Propensity score weighting using inverse probability treatment weights was used to balance beneficiary characteristics and a generalized linear regression with log-link function and Gamma distribution was run to determine per-member-per-month cost and prosthetic device cost. A 10-year Congressional Budget Office-style score was conducted. A logistic regression was run for the fallers analysis.

RESULTS

Microprocessor knee provision to K2 beneficiaries reduced injured fallers by 18.5% and resulted in medical savings of $1,351 per-member-per-month, amortizing the $25,075 difference between the MPK and nonmicroprocessor knee in 19 months. Providing MPKs to K2 users resulted in cumulative Medicare savings of $410.3 million over 10 years.

CONCLUSION

The MPK prosthetic device could provide meaningful safety benefits to the K2 population and result in fiscal savings to Medicare at both the person and population levels.

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.

Prosthetic Rehabilitation of a Female With Bilateral Transfemoral Amputation in Japan: A Case Report

Individuals with bilateral transfemoral (TF) amputation experience difficulties when walking with lower limb prostheses. Walking with prostheses is even more difficult when the cause of the amputation is nontraumatic, or the gender is female. We provided prosthetic rehabilitation to a woman who underwent bilateral TF amputation due to internal disease.  A 42-year-old woman underwent bilateral TF amputation for ischemic necrosis of the lower extremities during septic shock treatment. Upon admission to our convalescent rehabilitation ward 3 months after surgery, the patient weighed 32 kg and was underweight. After admission, she underwent strength training of the trunk and hip muscles, hip joint range of motion exercises, and bottom shuffle exercises on the physical therapy table. The prosthetist created stubby prostheses for standing and standing-up exercises on the floor, as well as gait exercises. We gradually extended the length of her prostheses and subsequently switched her knee joints to Ottobock locking and polycentric knees and eventually to Kenevo, which are microprocessor-controlled prosthetic knees (MPK). During occupational sessions, she practiced household activities such as washing dishes, cleaning, and cooking while wearing her prostheses. Six months after admission, the patient was discharged and could walk outdoors alone with two canes without using a wheelchair. At discharge, the Kenevo modes were Mode C on the right and Mode B + on the left. The patient's weight recovered to 41 kg. The patient completed the 10-meter walk test at 0.50 m/s at a comfortable walking speed, the 6-minute walk test at 180 meters, and the timed up and go (TUG) test in 26 seconds. The motor Functional Independence Measure (FIM) score was improved from 60 on admission to 83 on discharge.  Strengthening the hip and trunk muscles, improving endurance and balance, preventing hip contracture, and maintaining the hip range of motion are necessary for walking with bilateral TF prostheses. In the prosthetic rehabilitation of bilateral TF amputations, stubby prostheses, protocols for gradual extension of the prosthetic length, and Kenevo, a mode-changeable MPK, are helpful. MPK is essential for individuals with bilateral TF amputations to walk independently and use their prostheses daily. This report is a valuable reference for healthcare professionals involved with bilateral TF amputees in the future who need prosthetic rehabilitation.

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.

Development of an item bank for measuring prosthetic mobility in people with lower limb amputation: The Prosthetic Limb Users Survey of Mobility (PLUS-M)

BACKGROUND

Achieving mobility with a prosthesis is a common post-amputation rehabilitation goal and primary outcome in prosthetic research studies. Patient-reported outcome measures (PROMs) available to measure prosthetic mobility have practical and psychometric limitations that inhibit their use in clinical care and research.

OBJECTIVE

To develop a brief, clinically meaningful, and psychometrically robust PROM to measure prosthetic mobility.

DESIGN

A cross-sectional study was conducted to administer previously developed candidate items to a national sample of lower limb prosthesis users. Items were calibrated to an item response theory model and two fixed-length short forms were created. Instruments were assessed for readability, effective range of measurement, agreement with the full item bank, ceiling and floor effects, convergent validity, and known groups validity.

SETTING

Participants were recruited using flyers posted in hospitals and prosthetics clinics across the United States, magazine advertisements, notices posted to consumer websites, and direct mailings.

PARTICIPANTS

Adult prosthesis users (N = 1091) with unilateral lower limb amputation due to traumatic or dysvascular causes.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Candidate items (N = 105) were administered along with the Patient Reported Outcome Measurement Information System Brief Profile, Prosthesis Evaluation Questionnaire - Mobility Subscale, and Activities-Specific Balance Confidence Scale, and questions created to characterize respondents.

RESULTS

A bank of 44 calibrated self-report items, termed the Prosthetic Limb Users Survey of Mobility (PLUS-M), was produced. Clinical and statistical criteria were used to select items for 7- and 12-item short forms. PLUS-M instruments had an 8th grade reading level, measured with precision across a wide range of respondents, exhibited little-to-no ceiling or floor effects, correlated expectedly with scores from existing PROMs, and differentiated between groups of respondents expected to have different levels of mobility.

CONCLUSION

The PLUS-M appears to be well suited to measuring prosthetic mobility in people with lower limb amputation. PLUS-M instruments are recommended for use in clinical and research settings.

Clinical evaluation of fall risk in older adults who use lower-limb prostheses: A scoping review

BACKGROUND

No reviews or evidence-based clinical protocols exist to evaluate fall risk in older adults who use lower-limb prostheses, despite falls being prevalent and costly in this population. This scoping review sought to determine assessments, defined as clinical outcome measures and gait parameters, associated with fall risk in this population to determine if a systematic review is warranted and help inform an evidence-based clinical protocol.

METHODS

Google Scholar, PubMed, and Scopus were searched on April 19th, 2022 to include peer-reviewed original research. Included articles reported relationships between falls and clinical outcome measures or gait parameters in older adults who use transtibial or transfemoral prostheses. Clinical outcome measures included self-reported questionnaires and functional mobility tests. Gait parameters included spatiotemporal, kinematic, and kinetic data during walking and stair negotiation.

RESULTS

Nineteen articles were included. Clinical outcome measure scores, gait parameter data, and cutoff scores by fall status (nonfallers, single fallers, recurrent fallers) were summarized. Six articles determined clinical outcome measures that had statistically significant associations with falls, and two articles determined gait parameters that had statistically significant associations with falls.

CONCLUSIONS

The majority of articles found no clinical outcome measure or gait parameter alone was effective at identifying fall risks in this population. Future research should evaluate a combination of assessments and collect prospective fall data to move towards establishing an evidence-based protocol to evaluate fall risk in older adults using lower-limb prostheses.

Amputation and prosthetics of the lower extremity: The 2020 Dutch evidence-based multidisciplinary guideline

BACKGROUND

Lower-limb amputations are rare but debilitating events in the lives of affected persons. Treatment of persons with amputation inherently involves many different health care professions at different stages leading to and after an amputation. There are prevailing clinical questions within the work field related to different facets of care including peri/postoperative aspects, prosthetic components, rehabilitation treatment, and health care processes.

OBJECTIVES

To provide an up-to-date multidisciplinary evidence-based guideline for health care professionals involved in the treatment of persons with lower-limb amputation in the Netherlands.

METHODS

Identification of key questions in a focus group, systematic review of the evidence (up to March 2019, using Embase and MEDLINE databases), and weighing considerations, culminating in clinical recommendations.

RESULTS

Twelve key questions were formulated. Recommendations of two key questions were upheld in line with the previous 2012 guideline. Ten systematic literature searches were performed, leading to the inclusion of 59 studies.

CONCLUSION

A summary of evidence-based conclusions, considerations, and recommendations of the 2020 guideline is presented.

The effect of microprocessor controlled exo-prosthetic knees on limited community ambulators: systematic review and meta-analysis

PURPOSE

The clinical benefits of microprocessor-controlled prosthetic knees (MPKs) in community ambulators have been well-established. A systematic review in limited community ambulators published in 2014 found benefits in safety, performance-based, and patient-reported outcomes. This work updates the previous analysis to the current state of the published evidence.

METHODS

Systematic review and meta-analysis of the effect of MPKs in limited community ambulators.

RESULTS

Thirteen research projects presented in 15 publications were identified. Overall validity was "high" in nine studies, "moderate" in three, and "low" in one. The literature described a total of 2366 patients, with 704 classified as limited community ambulators. The use of MPKs in limited community ambulators led to a reduction in falls (SMD g: -0.59; 95% confidence interval (CI) [-0.85, -0.32; I²=0%]), fear of falling (SMD g: 1.2; 95%CI [0.55, 1.85; I²=80%]), risk of falling as indicated by the TUG (SMD g: -0.45, 95%CI [-0.87, -0.02; I²=0%]), an improvement in mobility grade (0.51; 95%CI [0.47,0.55]), self-selected walking speed (SMD g: 0.47; 95%CI [0.14,0.81; I²=0%]), and patient-reported ambulation (MD 9.32; 95%CI [3.61, 15.02; I²=7%]), and utility (MD 7.76; 95%CI [2.05-13.47; I²=0%]). Other outcomes exhibited trends in favor of MPK use or remained insensitive. No outcome was identified favoring non-MPKs.

CONCLUSIONS

These results suggest that MPKs may be considered a valuable therapeutic option in limited community ambulators with a transfemoral amputation.Implications for rehabilitationAbove knee amputees may be treated with a large variety of artificial exo-prosthetic knee components.Microprocessor-controlled prosthetic knees have proven to be advantageous and cost effective for community ambulators.The current analysis shows similar effects in safety, mobility, and patient perception also for limited community ambulators.Microprocessor-controlled prosthetic knees are a viable therapeutic option for limited community ambulators.

A review of user needs to drive the development of lower limb prostheses

Background

The development of bionic legs has seen substantial improvements in the past years but people with lower-limb amputation still suffer from impairments in mobility (e.g., altered balance and gait control) due to significant limitations of the contemporary prostheses. Approaching the problem from a human-centered perspective by focusing on user-specific needs can allow identifying critical improvements that can increase the quality of life. While there are several reviews of user needs regarding upper limb prostheses, a comprehensive summary of such needs for those affected by lower limb loss does not exist.

Methods

We have conducted a systematic review of the literature to extract important needs of the users of lower-limb prostheses. The review included 56 articles in which a need (desire, wish) was reported explicitly by the recruited people with lower limb amputation (N = 8149).

Results

An exhaustive list of user needs was collected and subdivided into functional, psychological, cognitive, ergonomics, and other domain. Where appropriate, we have also briefly discussed the developments in prosthetic devices that are related to or could have an impact on those needs. In summary, the users would like to lead an independent life and reintegrate into society by coming back to work and participating in social and leisure activities. Efficient, versatile, and stable gait, but also support to other activities (e.g., sit to stand), contribute to safety and confidence, while appearance and comfort are important for the body image. However, the relation between specific needs, objective measures of performance, and overall satisfaction and quality of life is still an open question.

Conclusions

Identifying user needs is a critical step for the development of new generation lower limb prostheses that aim to improve the quality of life of their users. However, this is not a simple task, as the needs interact with each other and depend on multiple factors (e.g., mobility level, age, gender), while evolving in time with the use of the device. Hence, novel assessment methods are required that can evaluate the impact of the system from a holistic perspective, capturing objective outcomes but also overall user experience and satisfaction in the relevant environment (daily life).

The Kenevo microprocessor-controlled prosthetic knee compared with non-microprocessor-controlled knees in individuals older than 65 years in Sweden: A cost-effectiveness and budget-impact analysis

BACKGROUND

Growing evidence suggests that individuals with transfemoral amputation or knee disarticulation using a prosthesis equipped with a microprocessor-controlled knee (MPK) benefit from enhanced mobility and safety, including less falls. In elderly individuals, high mortality rates are assumed to reduce the expected useful life of MPKs, and this raises concerns regarding their economic effectiveness.

OBJECTIVE

To investigate the cost-effectiveness and budget impact of the Kenevo/MPK (Ottobock, Germany) compared with non-microprocessor-controlled knees (NMPKs) in people older than 65 years at the time of transfemoral amputation/knee disarticulation, from a Swedish payer's perspective.

METHODS

A decision-analytic model was developed to conduct the economic analysis of the Kenevo/MPK. Model parameters were derived from Swedish databases and published literature. Univariate and probabilistic sensitivity analyses were performed to explore parameter uncertainty.

RESULTS

Compared with NMPKs, the Kenevo/MPK reduced the frequency of hospitalizations by 137 per 1,000 person years while the frequency of fatal falls was reduced by 19 per 1,000 person-years in the simulation. Over a 25-year time horizon, the incremental cost-effectiveness ratio was EUR11,369 per quality-adjusted life year. The probability of the MPK being cost-effective at a threshold of EUR40,000 per quality-adjusted life year was 99%. The 5-year budget impact model predicted an increase in payer expenditure of EUR1.76 million if all new patients received a Kenevo/MPK, and 50% of current NMPK users switched to the MPK.

CONCLUSIONS

Results of the modeling suggest that the Kenevo/MPK is likely to be cost-effective for elderly individuals, primarily because of a reduction in falls.

Impact of microprocessor prosthetic knee on mobility and quality of life in patients with lower limb amputation: a systematic review of the literature

INTRODUCTION

Advanced technologies have made available the development of microprocessor prosthetic knee (MPK) to improve autonomy of patients with lower limb amputation. In the present systematic review, we aimed to evaluate the impact of the use of all types of MPK on patients' functional status and quality of life.

EVIDENCE ACQUISITION

We conducted this review according to the PRISMA Guidelines on Medline (via Ovid), Scopus and SportDiscuss. All identified articles were screened for their eligibility by two reviewers using Covidence software. The Cochrane Risk of Bias (RoB) or the NIH Quality Assessment Tool were used to assess the quality of the studies.

EVIDENCE SYNTHESIS

Eighteen articles were included in the present review (7 randomized controlled trials - RCT), 6 cross-sectional and 5 follow-up studies). Number of participants included varied from 20 to 602, protocols' length varied from a single session to 12 weeks of use of MPK. Taken together, MPK users compared to NMPK users tend to present better functional status and mobility. Quality of life was also positively impacted in MPK users. On the other hand, the superiority of more advanced MPKs such as the Genium^® is less clear, especially given the improvements over time of other MPKs such as the C-leg^® and the Rheo knee^®.

CONCLUSIONS

Based on our results, while it is clear that MPKs outperform NMPKs both for functional status and quality of life, additional benefits of one MPK over another is less clear. Future studies are needed to clarify these aspects.

Survey of transfemoral amputee experience and priorities for the user-centered design of powered robotic transfemoral prostheses

BACKGROUND

Transfemoral amputees experience a complex host of physical, psychological, and social challenges, compounded by the functional limitations of current transfemoral prostheses. However, the specific relationships between human factors and prosthesis design and performance characteristics have not yet been adequately investigated. The present study aims to address this knowledge gap.

METHODS

A comprehensive single-cohort survey of 114 unilateral transfemoral amputees addressed a broad range of demographic and clinical characteristics, functional autonomy, satisfaction and attitudes towards their current prostheses, and design priorities for an ideal transfemoral prosthesis, including the possibility of active assistance from a robotic knee unit. The survey was custom-developed based on several standard questionnaires used to assess motor abilities and autonomy in activities of daily living, prosthesis satisfaction, and quality of life in lower-limb amputees. Survey data were analyzed to compare the experience (including autonomy and satisfaction) and design priorities of users of transfemoral prostheses with versus without microprocessor-controlled knee units (MPKs and NMPKs, respectively), with a subsequent analyses of cross-category correlation, principal component analysis (PCA), cost-sensitivity segmentation, and unsupervised K-means clustering applied within the most cost-sensitive participants, to identify functional groupings of users with respect to their design priorities.

RESULTS

The cohort featured predominantly younger (< 50 years) traumatic male amputees with respect to the general transfemoral amputee population, with pronounced differences in age distribution and amputation etiology (traumatic vs. non-traumatic) between MPK and NMPK groups. These differences were further reflected in user experience, with MPK users reporting significantly greater overall functional autonomy, satisfaction, and sense of prosthesis ownership than those with NMPKs, in conjunction with a decreased incidence of instability and falls. Across all participants, the leading functional priorities for an ideal transfemoral prosthesis were overall stability, adaptability to variable walking velocity, and lifestyle-related functionality, while the highest-prioritized general characteristics were reliability, comfort, and weight, with highly variable prioritization of cost according to reimbursement status. PCA and user clustering analyses revealed the possibility for functionally relevant groupings of prosthesis features and users, based on their differential prioritization of these features-with implications towards prosthesis design tradeoffs.

CONCLUSIONS

This study's findings support the understanding that when appropriately prescribed according to patient characteristics and needs in the context of a proactive rehabilitation program, advanced transfemoral prostheses promote patient mobility, autonomy, and overall health. Survey data indicate overall stability, modularity, and versatility as key design priorities for the continued development of transfemoral prosthesis technology. Finally, observed associations between prosthesis type, user experience, and attitudes concerning prosthesis ownership suggest both that prosthesis characteristics influence device acceptance and functional outcomes, and that psychosocial factors should be specifically and proactively addressed during the rehabilitation process.

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.

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.

Using a microprocessor knee (C-Leg) with appropriate foot transitioned individuals with dysvascular transfemoral amputations to higher performance levels: a longitudinal randomized clinical trial

Background

Individuals with transfemoral amputations who are considered to be limited community ambulators are classified as Medicare functional classification (MFCL) level K2. These individuals are usually prescribed a non-microprocessor controlled knee (NMPK) with an appropriate foot for simple walking functions. However, existing research suggests that these individuals can benefit from using a microprocessor controlled knee (MPK) and appropriate foot for their ambulation, but cannot obtain one due to insurance policy restrictions. With a steady increase in older adults with amputations due to vascular conditions, it is critical to evaluate whether advanced prostheses can provide better safety and performance capabilities to maintain and improve quality of life in individuals who are predominantly designated MFCL level K2. To decipher this we conducted a 13 month longitudinal clinical trial to determine the benefits of using a C-Leg and 1M10 foot in individuals at K2 level with transfemoral amputation due to vascular disease. This longitudinal clinical trial incorporated recommendations prescribed by the lower limb prosthesis workgroup to design a study that can add evidence to improve reimbursement policy through clinical outcomes using an MPK in K2 level individuals with transfemoral amputation who were using an NMPK for everyday use.

Methods

Ten individuals (mean age: 63 ± 9 years) with unilateral transfemoral amputation due to vascular conditions designated as MFCL K2 participated in this longitudinal crossover randomized clinical trial. Baseline outcomes were collected with their current prosthesis. Participants were then randomized to one of two groups, either an intervention with the MPK with a standardized 1M10 foot or their predicate NMPK with a standardized 1M10 foot. On completion of the first intervention, participants crossed over to the next group to complete the study. Each intervention lasted for 6 months (3 months of acclimation and 3 months of take-home trial to monitor home use). At the end of each intervention, clinical outcomes and self-reported outcomes were collected to compare with their baseline performance. A generalized linear model ANOVA was used to compare the performance of each intervention with respect to their own baseline.

Results

Statistically significant and clinically meaningful improvements were observed in gait performance, safety, and participant-reported measures when using the MPK C-Leg + 1M10 foot. Most participants were able to achieve higher clinical scores in gait speed, balance, self-reported mobility, and fall safety, while using the MPK + 1M10 combination. The improvement in scores were within range of scores achieved by individuals with K3 functional level as reported in previous studies.

Conclusions

Individuals with transfemoral amputation from dysvascular conditions designated MFCL level K2 benefited from using an MPK + appropriate foot. The inference and evidence from this longitudinal clinical trial will add to the knowledgebase related to reimbursement policy-making.

Trial registration This study is registered on clinical trials.gov with the study title “Functional outcomes in dysvascular transfemoral amputees” and the associated ClinicalTrials.gov Identifier: NCT01537211. The trial was retroactively registered on February 7, 2012 after the first participant was enrolled.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-021-00879-3.

A qualitative pilot study exploring reasons for prosthetic preference in a veteran amputee population

Background/Aims

For people with transfemoral amputations, newer technology, microprocessor-controlled prosthetic limbs, offer a level of performance that exceeds that of older, non-microprocessor controlled limbs. They are often requested by members of Her Majesty's Armed Forces who have been discharged from service (veterans) during applications for replacement limbs. However, as microprocessor-controlled prosthetic limbs cost far exceeds that of non-microprocessor controlled limbs, justification for their provision is essential to ensure that they are seen as value for money for the NHS in the UK. To date, literature focuses on measures of objective performance when demonstrating the value of one limb over another, but it ignores individual lifestyles within this process. This project aims to explore the reasons underpinning individual requests for specific types of prosthetic lower limb in a population of veterans with amputations.

Methods

This pilot study explored secondary data, consisting of patient statements, from the evaluation process associated with applications for new microprocessor-controlled prosthetic limbs. The data referred to a sample population of non-serving veterans with amputations who attended a veteran prosthetic centre for the ongoing maintenance and replacement of their prosthetic limbs (n=15).

Results

Findings from the study suggest an interconnection between function, psychology and emotional context. Individual statements demonstrate that, while functional performance influences choice, it is the application of function to life and lifestyle that underpins the meaning of improvements in performance for the individual.

Conclusions

Further research investigating the meaning of limb performance to the life of an individual is essential to facilitate effective prescription of limbs that meet individual need, and ensuring accurate distribution of what are currently limited funds.

Advanced techniques in amputation surgery and prosthetic technology in the lower extremity

Bone-anchored implants give patients with unmanageable stump problems hope for drastic improvements in function and quality of life and are therefore increasingly considered a viable solution for lower-limb amputees and their orthopaedic surgeons, despite high infection rates.Regarding diversity and increasing numbers of implants worldwide, efforts are to be supported to arrange an international bone-anchored implant register to transparently overview pros and cons.Due to few, but high-quality, articles about the beneficial effects of targeted muscle innervation (TMR) and regenerative peripheral nerve interface (RPNI), these surgical techniques ought to be directly transferred into clinical protocols, observations and routines.Bionics of the lower extremity is an emerging cutting-edge technology. The main goal lies in the reduction of recognition and classification errors in changes of ambulant modes. Agonist-antagonist myoneuronal interfaces may be a most promising start in controlling of actively powered ankle joints.As advanced amputation surgical techniques are becoming part of clinical routine, the development of financing strategies besides medical strategies ought to be boosted, leading to cutting-edge technology at an affordable price.Microprocessor-controlled components are broadly available, and amputees do see benefits. Devices from different manufacturers differ in gait kinematics with huge inter-individual varieties between amputees that cannot be explained by age. Active microprocessor-controlled knees/ankles (A-MPK/As) might succeed in uneven ground-walking. Patients ought to be supported to receive appropriate prosthetic components to reach their everyday goals in a desirable way.Increased funding of research in the field of prosthetic technology could enhance more high-quality research in order to generate a high level of evidence and to identify individuals who can profit most from microprocessor-controlled prosthetic components. Cite this article: EFORT Open Rev 2020;5:724-741. DOI: 10.1302/2058-5241.5.190070.

Quality of life, body image, and mobility in lower-limb amputees using high-tech prostheses: A pragmatic trial

BACKGROUND

High-tech prostheses are supposed to achieve better functional recovery over mechanical-controlled prostheses in lower-limb amputees. However, quantitative data are insufficient.

OBJECTIVE

We aimed to evaluate changes in quality of life, life satisfaction, perception of body image, and functional performance of lower-limb amputees when using a mechanical-controlled prosthesis versus a microprocessor-controlled knee (MPK) or transtibial vacuum-assisted suspension system (VASS) prosthesis.

METHODS

In this pragmatic study, 57 lower-limb amputees were assessed with the Satisfaction with the Prosthesis Questionnaire (SATPRO), revised Amputee Body Image Scale (ABIS-R), Trinity Amputation and Prosthesis Experience Scales (TAPES), Medical Outcomes Study Short Form-36 (SF-36) and 6-min walk test (6MWT). All assessments were performed under 2 conditions (i.e., using a mechanical-controlled prosthesis vs. an MPK/VASS prosthesis.

RESULTS

Amputees who used an MPK/VASS prosthesis showed significant increases in all SF-36 subscale scores and all subscale scores of TAPES except adjustment to limitation (P=0.156). The amputees showed clinically relevant improvements in 6MWT (P<0.001) and in SATPRO and ABIS-R scores (P<0.001).

CONCLUSION

Lower-limb amputees using an MPK/VASS prosthesis had better life satisfaction, quality of life and functional performance than those using a mechanical-controlled prosthesis.

Impact of C-LEG on mobility, satisfaction and quality of life in a multicenter cohort of femoral amputees

BACKGROUND

In some countries, the microprocessor-controlled C-LEG knee joint is reimbursed by the national health insurance for transfemoral amputees under certain conditions. However, whether users really benefit from such a technology in their daily life is unknown.

OBJECTIVE

To observe the performance of active C-LEG users in terms of locomotor ability and activities, satisfaction and quality of life after 6 months of wearing the prosthesis in real-life conditions.

METHODS

This multicenter observational study investigated locomotor ability [Locomotor Capability Index 5 (LCI-5)], satisfaction [Quebec User Evaluation of Satisfaction with Assistive Device 2.0 (QUEST 2.0)] and quality of life [Medical Outcomes Study Short Form 36 (SF-36)] at the beginning (T0) and end (T1) of the C-LEG test period and at 6 months (T2) after the confirmed prescription of the C-LEG. Information was also collected on the use of walking aids, daily wear of the prosthesis, falls and adverse events.

RESULTS

We enrolled 102 participants; 81 were assessed at T1 (62 had a previous prosthesis) and 56 were followed up after 6 months (45 had a previous prosthesis). For participants who had previously been fitted with a prosthetic knee, which was mechanical in almost all cases, as compared with baseline, the use of C-LEG significantly improved locomotor ability (LCI-5 52.6 vs. 46.7, P<0.001), satisfaction (QUEST score 4.6 vs. 3.7, P<0.001) and physical quality of life (SF-36 physical component summary score 51.1 vs. 45.3, P<0.001). In addition, daily use of the prosthesis was higher and use of walking aids and frequency of falls were lower as compared with the previous period.

CONCLUSIONS

Active transfemoral amputees with prescription of the C-LEG knee joint showed improved function, satisfaction and physical quality of life after 6 months of wear as compared with their previous prosthesis.

Cost-effectiveness and budget impact of the microprocessor-controlled knee C-Leg in transfemoral amputees with and without diabetes mellitus

BACKGROUND

The safe use of a prosthesis in activities of daily living is key for transfemoral amputees. However, the number of falls varies significantly between different prosthetic device types. This study aims to compare medical and economic consequences of falls in transfemoral amputees who use the microprocessor-controlled knee joint C-Leg with patients who use non-microprocessor-controlled (mechanical) knee joints (NMPK). The main objectives of the analysis are to investigate the cost-effectiveness and budget impact of C-Legs in transfemoral amputees with diabetes mellitus (DM) and without DM in Germany.

METHODS

A decision-analytic model was developed that took into account the effects of prosthesis type on the risk of falling and fall-related medical events. Cost-effectiveness and budget impact analyses were performed separately for transfemoral amputees with and without DM. The study took the perspective of the statutory health insurance (SHI). Input parameters were derived from the published literature. Univariate and probabilistic sensitivity analyses (PSA) were performed to investigate the impact of changes in individual input parameter values on model outcomes and to explore parameter uncertainty.

RESULTS

C-Legs reduced the rate of fall-related hospitalizations from 134 to 20 per 1000 person years (PY) in amputees without DM and from 146 to 23 per 1000 PY in amputees with DM. In addition, the C-Leg prevented 15 or 14 fall-related death per 1000 PY. Over a time horizon of 25 years, the incremental cost-effectiveness ratio (ICER) was 16,123 Euro per quality-adjusted life years gained (QALY) for amputees without DM and 20,332 Euro per QALY gained for amputees with DM. For the period of 2020-2024, the model predicted an increase in SHI expenditures of 98 Mio Euro (53 Mio Euro in prosthesis users without DM and 45 Mio Euro in prosthesis users with DM) when all new prosthesis users received C-Legs instead of NMPKs and 50% of NMPK user whose prosthesis wore out switched to C-Legs. Results of the PSA showed moderate uncertainty and a probability of 97-99% that C-Legs are cost-effective at an ICER threshold of 40,000 Euro (≈ German GDP per capita in 2018) per QALY gained.

CONCLUSION

Results of the study suggest that the C-Leg provides substantial additional health benefits compared with NMPKs and is likely to be cost-effective in transfemoral amputees with DM as well as in amputees without DM at an ICER threshold of 40,000 Euro per QALY gained.

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.