Comparison of mobility and user satisfaction between a microprocessor knee and a standard prosthetic knee: a summary of seven single-subject trials

Creating Adjusted Scores Targeting mobiLity Empowerment (CASTLE 1): determination of normative mobility scores after lower limb amputation for each year of adulthood

PURPOSE

As United States healthcare transitions from traditional fee-for-service models to value-based care, there is increased need to demonstrate quality care through clinical outcomes. Therefore, the purpose of this study was to create equations to calculate an expected mobility score for lower limb prosthesis users specific to their age, etiology, and amputation level to provide benchmarks to qualify good outcomes.

MATERIALS AND METHODS

A retrospective cross-sectional analysis of outcomes collected during clinical care was performed. Individuals were grouped based on amputation level (unilateral above-knee (AKA) or below-knee (BKA)) and etiology (trauma or diabetes/dysvascular (DV)). The mean mobility score (PLUS-M® T-score) for each year of age was calculated. AKAs were further stratified into having a microprocessor knee (MPK) or non-microprocessor (nMPK) for secondary analysis.

RESULTS

As expected, average prosthetic mobility declined with age. Overall, BKAs had higher PLUS-M T-scores compared to AKAs and trauma etiologies had higher scores compared to DV. For AKAs, those with a MPK had higher T-scores compared to those with a nMPK.

CONCLUSIONS

Results from this study provide average mobility for adult patients across every year of life. This can be leveraged to create a mobility adjustment factor to qualify good outcomes in lower limb prosthetic care.

Human-Prosthetic Interaction (HumanIT): A study protocol for a clinical trial evaluating brain neuroplasticity and functional performance after lower limb loss

BACKGROUND

Lower limb amputation contributes to structural and functional brain alterations, adversely affecting gait, balance, and overall quality of life. Therefore, selecting an appropriate prosthetic ankle is critical in enhancing the well-being of these individuals. Despite the availability of various prostheses, their impact on brain neuroplasticity remains poorly understood.

OBJECTIVES

The primary objective is to examine differences in the degree of brain neuroplasticity using magnetic resonance imaging (MRI) between individuals wearing a new passive ankle prosthesis with an articulated ankle joint and a standard passive prosthesis, and to examine changes in brain neuroplasticity within these two prosthetic groups. The second objective is to investigate the influence of prosthetic type on walking performance and quality of life. The final objective is to determine whether the type of prosthesis induces differences in the walking movement pattern.

METHODS

Participants with a unilateral transtibial amputation will follow a 24-week protocol. Prior to rehabilitation, baseline MRI scans will be performed, followed by allocation to the intervention arms and commencement of rehabilitation. After 12 weeks, baseline functional performance tests and a quality of life questionnaire will be administered. At the end of the 24-week period, participants will undergo the same MRI scans, functional performance tests and questionnaire to evaluate any changes. A control group of able-bodied individuals will be included for comparative analysis.

CONCLUSION

This study aims to unravel the differences in brain neuroplasticity and prosthesis type in patients with a unilateral transtibial amputation and provide insights into the therapeutic benefits of prosthetic devices. The findings could validate the therapeutic benefits of more advanced lower limb prostheses, potentially leading to a societal impact ultimately improving the quality of life for individuals with lower limb amputation.

TRIAL REGISTRATION

NCT05818410 (Clinicaltrials.gov).

Impacts of Microprocessor-Controlled Versus Non-microprocessor-Controlled Prosthetic Knee Joints Among Transfemoral Amputees on Functional Outcomes: A Comparative Study

INTRODUCTION

Selecting a prosthetic knee mechanism is an important part of transfemoral (TF) amputee rehabilitation. Prosthetic knee joint selection depends on the users' gait and their energy consumption. This study compares the feedback of transfemoral prosthesis users based on the prosthetic knee design self-reporting responses using the Prosthetic Evaluation Questionnaire (PEQ) outcome measure.

OBJECTIVE

This study aims to assess the impact of using a microprocessor-controlled prosthetic knee (MCPK) compared with a non-microprocessor-controlled prosthetic knee (NMCPK); feedback on the amputee usage can improve the clinical decision for proper prosthetic knee joint selection.

METHODS

This is a cross-sectional study with a total of 76 adult unilateral transfemoral amputees classified into two groups. The participants in the first group (38) used the MCPK (Genium, Otto Bock, Minneapolis, MN, USA), and the participants in the second group (38) used the NMCPK (hydraulic and total knee joints). Enrolment was based on a sequence of appointments where all participants answered the PEQ, with different subscale questions including utility (UT), sounds (SO), appearance (AP), residual limb health (RL), frustration (FR), perceived response (PR), social burden (SB), ambulation (AM), and quality of life (QoL). PEQ was filled out during the follow-up appointments at the prosthetic clinic through a visual analog scale (VAS). All data entered into a database were analyzed.

RESULT

The MCPK participants have significantly improved utility, appearance, ambulation, and total PEQ score, the same results as the male participants. Middle-adulthood (25-40 years) MCPK participants have a significant p-value in the score of utility, frustration, ambulation, and total PEQ score compared to early-adulthood (18-24 years) and late-adulthood (41-60 years) participants. Also, there was a significant improvement in the p-value in ambulation scores in participants using MCPK with amputations caused by diseases compared to amputations caused by trauma and congenital cause.

CONCLUSION

Transfemoral amputee prosthesis utility, natural gait, and ambulation improved when using MCPK compared to when using NMCPK during prosthetic rehabilitation.

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.

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.

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.

The utility of the single-subject method for comparison of temporal-spatial gait changes between a microprocessor and non-microprocessor prosthetic knees

BACKGROUND

Despite increasing knowledge about the potential benefits of advanced user-controlled technology, the decision about switching an individual prosthesis user from a non-microprocessor prosthetic knee to a microprocessor prosthetic knee is mainly based on clinician's experience rather than empirical evidence.

OBJECTIVES

To demonstrate the utility of single-subject design and data analysis for evaluating changes in temporal-spatial gait characteristics between walking with a non-microprocessor prosthetic knee and microprocessor prosthetic knee.

STUDY DESIGN

Single-subject ABA/BAB design.

METHODS

Seven non-microprocessor prosthetic knee users (all men, age 50-84 years, 3-40 years post-amputation) were transitioned through the ABA or BAB phases (A-NMPK, B-MPK, 5 weeks each). Four weekly gait evaluations were performed at three self-selected speeds with an electronic walkway. The non-microprocessor prosthetic knee-microprocessor prosthetic knee differences in stride length-cadence relationship, prosthetic weight acceptance, single-limb support, and step width were evaluated for each subject using the "non-overlap of all pairs" statistical method.

RESULTS

Most subjects improved temporal-spatial gait while on the microprocessor prosthetic knee; in only one subject, none of the 10 gait parameters were in favor of the microprocessor prosthetic knee. In the BAB group, longer use of the microprocessor prosthetic knee was associated with shorter prosthetic weight acceptance and longer single-limb support times across three speeds. Step width either improved with the microprocessor prosthetic knee or remained unchanged in most subjects.

CONCLUSION

The evidence of individual subject improvements in gait coordination, greater reliance on the prosthetic side, and better stability with the microprocessor prosthetic knee than non-microprocessor prosthetic knee over a range of walking speeds demonstrate the practical utility of the single-subject method in clinical decision-making.

CLINICAL RELEVANCE

The results demonstrate the use of the single-subject method for examining person-specific differences in temporal-spatial gait characteristics between walking with a non-microprocessor prosthetic knee and microprocessor prosthetic knee at three self-selected speeds. The method proved feasible and reliable for documenting changes in gait at the individual level, which is relevant for clinical practice.

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.

A conceptual framework for orthotic and prosthetic education

BACKGROUND

Variables that influence orthotic and prosthetic patient outcomes beyond direct care are poorly conceptualized for orthotic and prosthetic students. Restructuring educational curricula around important clinical reasoning variables (i.e. factors that may influence outcomes) could improve teaching, learning, and clinical practice.

OBJECTIVES

To propose an orthotic and prosthetic education framework to enhance the development of orthotic and prosthetic students' clinical reasoning skills.

STUDY DESIGN

Scoping review.

METHODS

We conducted a scoping review, identified variables of orthotic and prosthetic usability, and performed a qualitative thematic analysis through the lens of orthotic and prosthetic clinical educators to develop a conceptual framework for orthotic and prosthetic education.

RESULTS

Sorting of variables identified from the literature resulted in three thematic areas: (1) the state of functioning, disability, and health (International Classification of Functioning, Disability and Health); (2) orthotic and prosthetic technical properties, procedures, and appropriateness; and (3) professional service as part of orthotic and prosthetic interventions. The proposed orthotic and prosthetic education framework includes these three areas situated within the context of patient-centered care.

CONCLUSIONS

A conceptual framework was developed from variables identified in peer-reviewed literature. This orthotic and prosthetic education framework provides a structure to explore orthotic and prosthetic clinical reasoning and advance our teaching and assessment of students' clinical reasoning skills.

CLINICAL RELEVANCE

The proposed orthotic and prosthetic (O&P) education framework is intended to promote conversation about variables (e.g. health condition, procedures, services, and O&P principles) that influence O&P clinical practice outcomes and further advance our teaching and assessment of students' clinical reasoning skills.

Comparison between three types of prosthetic feet: a randomized double-blind single-subject multiple-rater trial

There are many prosthetic feet (Pfeet) on the market, and those in the same category do not necessarily have the same properties. We assessed three different Pfeet in terms of gait patterns on various terrains, balance and walking speed in a randomized double-blind controlled single-subject multiple-rater clinical trial. The patient was a 43-year old man who was an active prosthesis user and was amputated at transtibial level because of injury 17 years ago. One Solid Ankle Cushion Heel and two Dynamic Elastic Response (DER) Pfeet were tried six times in random order. The patient walked on flat, uneven, sloped terrain and stairs. Gait pattern was rated in comparison with the patient's previous prosthetic foot (Pfoot) by a physiatrist, physiotherapist, prosthetist and the patient; one-leg standing test on the prosthesis and 10-m walking test were also performed. The ratings differed significantly between the raters on each terrain, and there was no agreement among the raters regarding the ranking order of the Pfeet. All the Pfeet were generally rated as worse than the patient's previous one. The patient gave lower ratings on average than the professionals and recognized the order of the tested Pfeet. The results of one-leg standing test with one DER and the Solid Ankle Cushion Heel Pfoot were statistically significant better than with the other DER and the patient's previous Pfoot. Our study therefore indicates that rehabilitation professionals, when blinded, cannot always reliably observe differences in walking on different terrains with different Pfeet. The patient may feel the differences, but those may not match what the manufacturers declare.