Economic benefits of microprocessor controlled prosthetic knees: a modeling study

Comparing the lower limb joint biomechanics of the Power Knee, C-Leg and Rheo Knee during ramp and stair ambulation

One of the most significant developments in prosthetic knee technology has been the introduction of the Microprocessor-Controlled Prosthetic Knee (MPK). However, there is a lack of consensus over how different types of MPKs affect performance in different ambulation modes. In this study, we investigated the biomechanical differences in ramp and stair maneuvers when an individual with transfemoral amputation wears three commercial MPKs: the Össur Power Knee, the Össur Rheo Knee and the Ottobock C-Leg 4. The primary outcome variable for this study was the lower limb biological joint work, inclusive of the intact leg and prosthetic side hip. We hypothesized that (1) the Power Knee would result in lower biological work during ascent activities than the C-Leg and Rheo, both passive MPKs, and (2) the C-Leg and Rheo would result in lower biological work during descent activities than the Power Knee. During ramp ascent, the C-Leg was associated with lower biological joint work (p < 0.05) than the Power Knee. However, this relationship did not hold during stair ascent, where the Power Knee showed advantages for stair ascent with net reductions in biological joint work of 14.1% and 23.3% compared to the Rheo and C-leg, respectively. There were no significant differences in biological joint work between the knees during ramp and stair descent, indicating that choice of MPK may not be as important for descent activities. Our results demonstrate that differences are present between different types of MPKs during ascent activities which could prove useful in the prescription of these devices.

A disparity in prosthetic access for Ecuadorians with lower-limb amputation

BACKGROUND

Individuals with disabilities in low- and middle-income countries face barriers to rehabilitation services, including prosthetic care. Many countries, such as Ecuador, have adapted policies toward achieving universal health care coverage. For optimal functional outcomes, understanding the physical potential of prosthetic users is critical for appropriate prosthetic services.

OBJECTIVE

To determine the association between the functional level of Ecuadorians with lower-limb amputations and the functional level of their prosthetic componentry.

STUDY DESIGN

Retrospective study.

METHODS

A data set containing functional level (K-Level) of Ecuadorians with lower-limb amputations and the K-Level of their prosthesis was analyzed.

RESULTS

A diverse cohort of 164 participants with unilateral lower-limb amputation was recruited. Most participants were male (76.8%) with transfemoral amputations (56.1%) due to traumatic causes (51.2%). There was a small, positive, and statistically significant correlation between participants' functional levels and prosthetic componentry. Participants's functional levels were typically superior (median = 3) to their prostheses' functional abilities (median = 1), and 37.2% of participants did not have a prosthesis at the time of assessment.

CONCLUSIONS

These data indicated that participants whose physical ability exceeded basic ambulation lacked access to prostheses to match their functional abilities. The detailed disparity between physical potential and prosthetic access derived from the study's analysis supports investment into high functioning prosthetic componentry and further investigation into where gaps in care exist.

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.

Cost-effectiveness analysis of prosthesis provision for patients with transfemoral amputation in Tanzania

BACKGROUND

Limb loss leads to significant disability. Prostheses may mitigate this disability but are not readily accessible in low- and middle-income countries (LMICs). Cost-effectiveness data related to prosthesis provision in resource-constrained environments such as Tanzania is greatly limited.

OBJECTIVES

This study aimed to compare the cost-effectiveness of a prosthesis intervention compared with that of no prosthesis for persons with transfemoral amputations in an LMIC.

STUDY DESIGN

This is a prospective cohort study.

METHODS

Thirty-eight patients were prospectively followed up. Clinical improvement with prosthesis provision was measured using EuroQuol-5D, represented as quality-adjusted life years gained. Direct and indirect costs were measured. The primary outcome was incremental cost per quality-adjusted life year, measured at 1 year and projected over a lifetime using a Markov model. Reference case was set as a single prosthesis provided without replacement from a payer perspective. Additional scenarios included the societal perspective and replacement of the prosthesis. Uncertainty was measured with one-way probabilistic sensitivity analysis.

RESULTS

From the payer perspective, the incremental cost-effectiveness ratio (ICER) was $242 for those without prosthetic replacement over a lifetime, and the ICER was $390 for those with prosthetic replacement over a lifeime. From the societal perspective, prosthesis provision was both less expensive and more effective. One-way sensitivity analysis demonstrated the ICER remained below the willingness to pay threshold up to prosthesis costs of $763.

CONCLUSIONS

These findings suggest prosthesis provision in an LMIC may be cost-effective, but further studies with long-term follow up are needed to validate the results.

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.

Can microprocessor knees reduce the disparity in trips and falls risks between above and below knee prosthesis users?

While all lower limb prosthesis walkers have a high risk of tripping and/or falling, above knee prosthesis users are reported to fall more frequently. Recognising this, engineers designed microprocessor knees (MPK) to help mitigate these risks, but to what extent these devices reduce this disparity between above and below knee users is unclear. A service review was carried out in a prosthetic limb centre regarding the frequency of trips and falls in the previous four weeks. Data from unilateral, community ambulators were extracted. Ordered logistic regressions were applied to investigate whether MPKs mitigated the increased risk of trips and falls for prosthetic knee users, compared to below knee prosthesis users. Socio-demographics (sex, age), prosthesis (prosthesis type, years of use), health (comorbidities, vision, contralateral limb status, medication), and physical function (use of additional walking aids, activity level) were included as covariates. Of the 315 participants in the analysis, 57.5% reported tripping and 20.3% reported falling. Non-microprocessor prosthetic knee (non-MPK) users were shown to trip significantly more than below knee prosthesis users (OR = 1.96, 95% CI = 1.17–3.28). Other covariates showing a significant association included contralateral limb injuries (OR = 1.91, 95% CI = 1.15–3.18) and using an additional walking aid (OR = 1.99, 95% CI = 1.13–3.50). Non-MPK users were also shown to fall significantly more than below knee prosthesis users (OR = 3.34, 95% CI = 1.73–6.45), with no other covariates showing a significant association. MPK users did not show an increased frequency of trips (OR = 0.74, 95% CI = 0.33–1.64) or falls (OR = 0.34, 95% CI = 0.18–2.62), compared to below knee prosthesis users. Of those who tripped at least once in the previous four weeks, those using a non-MPK (OR = 2.73, 95% CI = 1.30–5.74) presented an increased frequency of falling. These findings provide evidence to suggest that the use of MPKs reduces the difference in falls risk between above knee and below knee prosthesis users, providing justification for their provision.

Editorial Opinion: Value Within the Prosthetic and Orthotic Provision Process

This Editorial presents an overview of the uptake of clinical outcome measures in the prosthetics and orthotics sector and considers how the use of objective measures contribute to demonstrating value provided. A decade ago, payors began to demand objective data to document costs vs. benefits from prosthetic and orthotic providers. The speed with which the sector responded to help develop measures and to begin to integrate them into practice is remarkable. This suggests an encouraging resilience and ability to adapt on the part of the sector as other trends such as Values-Based Health Care emerge to challenge the sector.

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.

Factors influencing physical activity among individuals with lower limb amputations: a qualitative study

PURPOSE

The purpose of this study was to explore the barriers and facilitators to physical activity from multiple stakeholder perspectives including individuals with LLA and health professionals.

MATERIALS AND METHODS

A qualitative descriptive study situated within an interpretive research paradigm was conducted. Semi-structured interviews were held with individuals with LLA recruited from rehabilitation hospitals in a metropolitan city in Canada. Health professionals with experience in amputation care were recruited from across Canada. Data were analysed using codebook thematic analysis.

RESULTS

Thirty-three individuals with LLA and eighteen health professionals participated. Six themes were generated which represent the perceived barriers and facilitators to physical activity. Themes including Informal and Formal Supports, Availability of and Access to Community Resources, and Fit and Function of the Prosthesis were perceived by many individuals as facilitators, while acting as a barrier for others depending on an individual's circumstances.

CONCLUSIONS

These findings provide us with a basis of understanding from which we can begin addressing barriers to physical activity for individuals with LLA, in support of developing patient-centred interventions and physical activity programs for this population. IMPLICATIONS FOR REHABILITATIONIrrespective of amputation etiology, individuals who have lower limb amputation experience several barriers to engaging in physical activity.Many system-level barriers to physical activity exist for people with lower limb amputation, which include lack of availability and access to community resources and specialised prostheses conducive to physical activity participation.A participatory approach engaging both patients and rehabilitation professionals can address the patient-provider discordance with respect to a patient's motivation and attitude towards physical activity participation by creating a supportive environment conducive to behaviour change.The development of future, patient-centered interventions, and physical activity programs for individuals with lower limb amputation must consider fear of falling as a prominent barrier to physical activity and devise potential strategies to address this barrier, by setting realistic and actionable goals.

Degree of Safety Against Falls Provided by 4 Different Prosthetic Knee Types in People With Transfemoral Amputation: A Retrospective Observational Study

OBJECTIVE

People with transfemoral amputation have balance and mobility problems and are at high risk of falling. An adequate prosthetic prescription is essential to maximize their functional levels and enhance their quality of life. This study aimed to evaluate the degree of safety against falls offered by different prosthetic knees.

METHODS

A retrospective study was conducted using data from a center for prosthetic fitting and rehabilitation. Eligible individuals were adults with unilateral transfemoral amputation or knee disarticulation. The prosthetic knee models were grouped into 4 categories: locked knees, articulating mechanical knees (AMKs), fluid-controlled knees (FK), and microprocessor-controlled knees (MPK). The outcome was the number of falls experienced during inpatient rehabilitation while wearing the prosthesis. Association analyses were performed with mixed-effect Poisson models. Propensity score weighting was used to adjust causal estimates for participant confounding factors.

RESULTS

Data on 1486 hospitalizations of 815 individuals were analyzed. Most hospitalizations (77.4%) were related to individuals with amputation due to trauma. After propensity score weighting, the knee category was significantly associated with falls. People with FK had the highest rate of falling (incidence rate = 2.81 falls per 1000 patient days, 95% CI = 1.96 to 4.02). FK significantly increased the risk of falling compared with MPK (incidence rate ratio [IRRFK-MPK] = 2.44, 95% CI = 1.20 to 4.96). No other comparison among knee categories was significant.

CONCLUSIONS

Fluid-controlled prosthetic knees expose inpatients with transfemoral amputation to higher incidence of falling than MPK during rehabilitation training.

IMPACT

These findings can guide clinicians in the selection of safe prostheses and reduction of falls in people with transfemoral amputation during inpatient rehabilitation.

Microprocessor knee technology reduces odds of incurring an injurious fall for individuals with diabetic/dysvascular amputation

Individuals with lower limb amputation have a high incidence of falls. An above-the-knee amputation and diabetes/vascular disease are both risk factors for falls. Microprocessor knee (MPK) technology may reduce falls in this population. The objective was to determine the association of MPKs and reduced injurious falls. A retrospective analysis of injurious falls within a large, national outcomes database was conducted. Inclusion was limited to adult K3 ambulators with unilateral, transfemoral or knee disarticulation amputation due to diabetes/vascular disease. There were 744 out of 881 individuals that did not receive an MPK. Results showed that 16.3% of non-MPK users experienced an injurious fall compared to 7.3% of MPK users (p=0.007). Not having an MPK resulted in significantly increased odds (unadjusted: OR: 2.47, 95% CI: 1.26 - 4.83, p=0.009; adjusted for confounders: OR: 2.52, 95% CI: 1.28 - 4.94, p=0.007) of incurring an injurious fall over a 6-month period. In conclusion, the current study found use of an MPK strongly associated with reduced injurious falls in a population of patients with amputation due to diabetes/vascular disease. The findings strongly support the use of MPK technology to mitigate fall risk, and in particular injurious falls requiring medical intervention.

Exploring the interaction of knee and ankle component use on mobility test performance in people with unilateral transfemoral amputation

BACKGROUND

Ankle-foot and knee components are important determinants of mobility for individuals with transfemoral amputation. Individually, advanced ankle-foot and knee components have been shown to benefit mobility in this group of people. However, it is not clear what effect a variety of combinations of ankle-foot and knee components have on mobility test performance.

OBJECTIVES

To assess whether outcomes from mobility tests in people with unilateral transfemoral amputation are influenced by varying combinations of ankle-foot and knee components.

STUDY DESIGNS

Repeated measures.

METHODS

Nine adults with unilateral transfemoral amputation completed the two-minute walk test, the timed up-and-go test, the L-test, and a custom locomotion course in four randomized prosthetic conditions. These conditions were each a combination of an ankle-foot component (rigid, nonarticulating [RIG] or hydraulically articulating [HYD]) and a knee component (non-microprocessor-controlled [NMPK] or microprocessor-controlled [MPK]). The test-retest reliability and concurrent validity of the custom locomotion course were also established.

RESULTS

The best performance in all mobility tests was associated with the MPK + HYD combination, followed by the MPK + RIG, NMPK + HYD, and NMPK + RIG combinations. This effect was statistically significant for the two-minute walk test (P = 0.01, = 0.36) and on threshold for the L-test (P = 0.05, = 0.36), but not statistically significant for the locomotion course (P = 0.07, = 0.38) or the timed up-and-go test (P = 0.12, = 0.22). Locomotion course performance had good to excellent test-retest reliability and strong concurrent validity.

CONCLUSION

Using a combination of a HYD ankle-foot and a MPK knee resulted in the highest performance in mobility tests. This was observed in contrast to combinations of prosthetic components that included a rigid ankle-foot component and/or a NMPK knee component.

Health Economics in the Field of Prosthetics and Orthotics: A Global Perspective

The rapid advancement of prosthetic and orthotic (P&O) technology raises the question how the industry can ensure that patients have access to the benefits and providers get paid properly and fairly by healthcare payers. This is a challenge that not only P&O but all areas of health technology face. In many areas of medicine and health products, such as drugs and medical devices, health-technology assessments (HTA) have become a standard procedure in the coverage and reimbursement process. In most countries, P&O is lagging behind that development, although some countries have already formalized HTA for prosthetic and orthotic products and may even use cost-effectiveness analyses to determine pricing and payment amounts. This article gives an overview on the coverage and reimbursement processes in the United States, Canada, Germany, France, Sweden, the United Kingdom, Poland, Japan, and China. This selection reflects the variety and diversity of coverage and reimbursement processes that the P&O industry faces globally. The paper continues with an overview on the necessary research and investment efforts that manufacturers will have to make in the future, and contemplates the likely consequences for the manufacturer community in the market place. Health economics may help support the transition from price-based to value-based coverage and reimbursement but will come at considerable costs to the industry.

A systematic review of health economic evaluation in orthotics and prosthetics: Part 2-orthotics

BACKGROUND

Health economic evaluations (HEEs) in orthotics are in their infancy. Identification of evidence gaps and method design issues will inform the design of future HEEs that advance knowledge and contributes to policy and investment decisions.

OBJECTIVES

The aim of this systematic review was to critically appraise the existing orthotic/prosthetic health economic evaluation literature and therefore determine evidence gaps, critical method design issues, and the extent to which the literature informs orthotic policy and investment decisions.

STUDY DESIGN

Systematic review.

METHODS

A range of databases were searched using intervention- and HEE-related terms. The Consolidated Health Economic Checklist-Extended and the Checklist for Health Economic Evaluation Reporting Standards were used to identify issues with method design and reporting.

RESULTS

Nine orthotic HEEs were narrowly focused on the cost-effectiveness of low-cost orthotic devices (eg, ankle orthoses for ankle sprains). Method design (eg, cost identification and valuation) and reporting issues (eg, lack of detail about the study population) limited the extent to which this literature can inform policy and investment decisions.

CONCLUSIONS

HEEs comparing a wider variety of interventions are required, particularly for commonly used orthoses (eg, ankle-foot orthoses) and clinical presentations (eg, post-stroke). There are opportunities to strengthen future orthotic HEEs by adopting method design features (eg, microcosting and sensitivity analyses) as recommended by HEE appraisal and reporting tools.

Evaluation of gait outcomes for individuals with established unilateral transfemoral amputation following the provision of microprocessor controlled knees in the context of a clinical service

BACKGROUND

Microprocessor controlled knees (MPKs) have been shown to improve gait outcomes for individuals with unilateral transfemoral amputation (TFA); however, previous studies have limitations, which may affect their applicability.

OBJECTIVES

To compare gait outcomes between non-MPK and MPK conditions within a large and diverse cohort of established TFAs in the pragmatic context of an operational clinical service and to identify any demographic variables that correlate with changes in gait outcomes.

STUDY DESIGN

This is a retrospective cohort study.

METHODS

Full-body three-dimensional motion capture and a portable breath gas analyser were used to evaluate gait-specific outcomes both pre-MPK and 6 months post-MPK provisions in TFAs (n = 32). The primary outcome measure was gait profile score, along with the following secondary outcome measures: walking velocity, step length, step length symmetry ratio, step time symmetry ratio, vertical ground reaction force symmetry index, base of support, center of mass deviation, and oxygen cost of walking.

RESULTS

Data showed statistically significant improvement in gait profile score from 11.2° ± 2.2° to 10.1° ± 2.1° (p < 0.01) between non-MPK and MPK conditions. Other outcomes which showed significant improvement were walking velocity (p < 0.01), step length (p < 0.01), vertical ground reaction force symmetry index (p < 0.01), and center of mass deviation (p < 0.05).

CONCLUSIONS

MPK provision offered significant gait improvements to this cohort of TFAs in an operational clinical setting. There still remains a large gap in gait outcomes between this cohort and those of healthy unimpaired adults. Improvements in socket design, prosthetic foot design, and physiotherapy intervention could further reduce this gap.

Cost Analyses of Prosthetic Devices: A Systematic Review

OBJECTIVE

To synthesize extant literature on the cost-effectiveness of prosthetic interventions and explore applicability to low- and middle-income country (LMIC) settings.

DATA SOURCES

A systematic literature review using subject headings including "prosthetics," "amputation," and "cost analysis" was performed with PubMed, Embase, and Web of Science search engines, yielding 1194 articles. An additional 22 articles were identified via backward citation searching for 1144 total after duplicate removal. The search was last run in May of 2019.

STUDY SELECTION

Studies were included if they conducted an economic analysis of an upper or lower extremity prosthetic device. Studies were excluded if (1) full text was unavailable in English; (2) study was a systematic review or meta-analysis; or (3) study did not have a prosthetic comparison group. Using DistillerSR software, 2 authors independently conducted title and abstract screening. One author conducted full-text screening. The proportion of initially identified studies that met final inclusion criteria was 1% (12 of 1144).

DATA EXTRACTION

Data were dually extracted by 2 authors and reviewed by 3 additional authors.

DATA SYNTHESIS

All included studies (N=12) examined lower extremity amputations comparing advanced technology. No studies were conducted in LMICs. Comparable data between studies demonstrated (1) the cost-effectiveness of microprocessor- over nonmicroprocessor-controlled knees for transfemoral amputation in high-income settings; (2) equivocal findings regarding osseointegrated vs socket-suspended prostheses; and (3) increased cost for ICEX and modular socket systems over patellar tendon-bearing socket systems with no functional improvement.

CONCLUSIONS

There are few prosthetic cost analyses in the literature. Additional analyses are needed to determine the direct and indirect costs associated with prosthetic acquisition, fitting, and maintenance; the costs of amputee rehabilitation; and long-term economic and quality-of-life benefits. Such studies may guide future prosthetic and rehabilitative care, especially in resource-austere settings where prosthetic needs are greatest.

A systematic review of health economic evaluations in orthotics and prosthetics: Part 1 - prosthetics

BACKGROUND

The extent to which current prosthetic health economic evaluations inform healthcare policy and investment decisions is unclear. To further the knowledge in this area, existing evidence gaps and method design issues must be identified, thereby informing the design of future research.

OBJECTIVES

The aim of this systematic review was to identify evidence gaps, critical method design and reporting issues and determine the extent to which the literature informs a wide range of policy and investment decisions.

STUDY DESIGN

Systematic review.

METHODS

A range of databases were searched using intervention- and health economic evaluation-related terms. Issues with methodological design and reporting were evaluated using the Consolidated Health Economic Checklist - Extended and the Checklist for Health Economic Evaluation Reporting Standards.

RESULTS

The existing health economic evaluation literature was narrowly focused on informing within-participant component decisions. There were common method design (e.g. time horizon too short) and reporting issues (e.g. competing intervention descriptions) that limit the extent to which this literature can inform policy and investment decisions.

CONCLUSION

There are opportunities to conduct a wider variety of health economic evaluations to support within- and across-sector policy and investment decisions. Changes to aspects of the method design and reporting are encouraged for future research in order to improve the rigour of the health economic evaluation evidence.

CLINICAL RELEVANCE

This systematic review will inform the clinical focus and method design of future prosthetic health economic evaluations. It will also guide readers and policy-makers in their interpretation of the current literature and their understanding of the extent to which the current literature can be used to inform policy and investment decisions.

Symmetry function in gait pattern analysis in patients after unilateral transfemoral amputation using a mechanical or microprocessor prosthetic knee

BACKGROUND

Above-knee amputations (AKAs) contribute to gait asymmetry. The level of asymmetry is affected by the type of knee prosthetic module. There is limited evidence suggesting that more technically advanced solutions (microprocessor modules; MicPK) are superior to less advanced ones (mechanical modules; MechPK). The study aimed to evaluate the variable range of hip and pelvic joint movements during gait and look for differentiating areas with an increased level of asymmetry of the gait cycle in individuals who underwent an AKA and are equipped with MicPK or MechPK.

METHODS

Twenty-eight individuals participated in the study; 14 were assigned to a study group of individuals who underwent a unilateral AKA, and the other 14 were healthy participants as a control group. The movement task was recorded using the optoelectronic SMART-E system following the standard Davis protocol (the Newington model). A new method of quantifying gait symmetry using the symmetry function (SF) is proposed. SF is an integral measure of absolute differences in time-standardized signals between sides throughout the whole cycle of motion variability.

RESULTS

In the frontal plane, there were significant differences between groups in the asymmetry of the range of movement in the hip joint of the intact limb. In the middle of the support phase, the intact limb was more adducted in individuals with MicPK and less abducted in people with MechPK (differences in mean 180%, p < 0.000; max 63%, p < 0.000; min 65%, p < 0.000). In the sagittal plane, the range of asymmetry of the flexion and thigh extension of the intact limb was similar to and only slightly different from the physiological gait. In the transverse plane, higher asymmetry values were noted for individuals with MicPK. In the final stage of the swing phase, the thigh was more rotated both externally and internally. The size of the asymmetry, when compared to gait of healthy individuals, reached 50% (differences in mean 115%, p < 0.232; max 62% p < 0.26; min 50, p < 0.154).

CONCLUSIONS

In the study group, the assessed ranges of pelvic and thigh movement in the hip joint differed only in the frontal plane. Individuals who underwent a unilateral above-knee amputation may gain less from using MicPK than anticipated.

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.

Canada's Prosthetic Coverage: a Review of Provincial Prosthetic Policy

The Canadian healthcare system serves as an example of equity and federal service to citizens across the world. However, it is not without its challenges. Prosthetic coverage across Canada is highly variable and largely unable to provide equal coverage for Canadian persons living with amputation. Many persons with limb loss are forced to rely upon personal resources, fundraising, or the charity of non-governmental organizations in order to meet this basic healthcare need. This disparity in the Canadian healthcare system is unusual and largely undescribed in the literature. We thus explore the nature of Canadian healthcare prosthetic coverage across Canada, investigating the variability in coverage, presence of prosthetic coverage policies, clarity of policy, eligibility criteria, and interval of prosthetic replacement. Our findings highlight potential areas for improvement within current Canadian healthcare policy.