Development of the AMPDECIDE Decision Aid to Facilitate Shared Decision Making in Patients Facing Amputation Secondary to Chronic Limb Threatening Ischemia.

INTRODUCTION: We developed a patient decision aid to enhance patient participation in amputation level decision making when there is a choice between a transmetatarsal or transtibial amputation. METHODS: In accordance with International Patient Decision Aid Standards, we developed an amputation level patient decision aid for patients who are being considered for either a transmetatarsal or transtibial amputation, incorporating qualitative literature data, quantitative literature data, qualitative provider and patient interviews, expert panel input and iterative patient feedback. RESULTS: The rapid qualitative literature review and qualitative interviews identified five domains outcome priority domains important to patients facing amputation secondary to chronic limb threatening ischemia: 1) the ability to walk, 2) healing and risk for reamputation, 3) rehabilitation program intensity, 4) ease of prosthetic use, and 5) limb length after amputation. The rapid quantitative review identified only two domains with adequate evidence comparing differences in outcomes between the two amputation levels: mobility and reamputation. Patient, surgeon, rehabilitation and decision aid expert feedback allowed us to integrate critical facets of the decision including addressing the emotional context of loss of limb, fear and anxiety as an obstacle to decision making, shaping the decision in the context of remaining life years, and how to facilitate patient knowledge of value tradeoffs. CONCLUSIONS: Amputation level choice is associated with significant outcome trade-offs. The AMPDECIDE patient decision aid can facilitate acknowledgment of patient fears, enhance knowledge of amputation level outcomes, assist patients in determining their personal outcome priorities, and facilitate shared amputation level decision making.

The Effect of Prosthetic Limb Sophistication and Amputation Level on Self-reported Mobility and Satisfaction With Mobility.

OBJECTIVE: To determine if lower limb prosthesis (LLP) sophistication is associated with patient-reported mobility and/or mobility satisfaction, and if these associations differ by amputation level. DESIGN: Cohort study that identified participants through a large national database and prospectively collected self-reported patient outcomes. SETTING: The Veterans Administration (VA) Corporate Data Warehouse, the National Prosthetics Patient Database, participant mailings, and phone calls. PARTICIPANTS: 347 Veterans who underwent an incident transtibial (TT) or transfemoral (TF) amputation due to diabetes and/or peripheral artery disease and received a qualifying LLP between March 1, 2018, and November 30, 2020. INTERVENTIONS: Basic, intermediate, and advanced prosthesis sophistication was measured by the accurate and reliable PROClass system. MAIN OUTCOME MEASURE: Patient-reported mobility using the advanced mobility subscale of the Locomotor Capabilities Index-5; mobility satisfaction using a 0-10-point Likert scale. RESULTS: Lower limb amputees who received intermediate or advanced prostheses were more likely to achieve advanced mobility than those who received basic prostheses, with intermediate nearing statistical significance at nearly twice the odds (adjusted odds ratio (aOR)=1.8, 95% confidence interval (CI), .98-3.3; P=.06). The association was strongest in TF amputees with over 10 times the odds (aOR=10.2, 95% CI, 1.1-96.8; P=.04). The use of an intermediate sophistication prosthesis relative to a basic prosthesis was significantly associated with mobility satisfaction (adjusted ß coefficient (aß)=.77, 95% CI, .11-1.4; P=.02). A statistically significant association was only observed in those who underwent a TT amputation (aß=.79, 95% CI, .09-1.5; P=.03). CONCLUSIONS: Prosthesis sophistication was not associated with achieving advanced mobility in TT amputees but was associated with greater mobility satisfaction. In contrast, prosthesis sophistication was associated with achieving advanced mobility in TF amputees but was not associated with an increase in mobility satisfaction.

Gender differences in prosthesis-related outcomes among veterans: Results of a national survey of U.S. veterans.

BACKGROUND: Women with lower extremity amputations (LEAs) tend to have poorer prosthesis-related outcomes than men, although the literature is sparse. To our knowledge, there are no prior studies examining prosthesis-related outcomes of women veterans with LEAs. OBJECTIVE: To examine gender differences (overall and by type of amputation) among veterans who underwent LEAs between 2005 and 2018, received care at the Veterans Health Administration (VHA) prior to undergoing amputation, and were prescribed a prosthesis. It was hypothesized that compared to men, women would report lower satisfaction with prosthetic services, poorer prosthesis fit, lower prosthesis satisfaction, less prosthesis use, and worse self-reported mobility. Furthermore, it was hypothesized that gender differences in outcomes would be more pronounced among individuals with transfemoral than among those with transtibial amputations. DESIGN: Cross-sectional survey. Linear regressions were used to assess overall gender differences in outcomes and gender differences based on type of amputation in a national sample of veterans. SETTING: VHA medical centers. PARTICIPANTS: The sample consisted of 449 veterans who self-identified their gender (women = 165, men = 284) with transtibial (n = 236), transfemoral (n = 135), and bilateral LEAs (n = 68) including all amputation etiologies. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Orthotics and Prosthetics User's Survey, Trinity Amputation and Prosthesis Experiences Scale, and Prosthetic Limb Users Survey of Mobility-Short Form were used to assess satisfaction with prosthetic services, prosthesis fit, prosthesis satisfaction, prosthesis use, and self-reported mobility. RESULTS: Women had poorer self-reported mobility than men (d = -0.26, 95% confidence interval -0.49 to -0.02, p < .05); this difference was small. There were no statistically significant gender differences in satisfaction with prosthetic services, prosthesis fit, prosthesis satisfaction, daily hours of prosthesis use, or by amputation type. CONCLUSIONS: Contrary to the hypothesis, prosthesis-related outcomes were similar between men and women with LEAs. Minimal differences may in part be due to receiving care from the VHA's integrated Amputation System of Care.

The effect of depression on prosthesis prescription in men and women who have undergone a lower limb amputation.

PURPOSE: To determine gender disparities and potential factors that modify prosthesis prescription practices in veteran patients who have undergone their first major unilateral amputation due to diabetes or peripheral arterial disease. MATERIALS AND METHODS: A retrospective cohort study using the VA Corporate Data Warehouse to compare prosthesis prescription rates and time to prescription between men and women veterans. The primary exposure was gender. The primary outcome was a qualifying prosthesis prescription within 12 months of the incident amputation. The secondary outcome was time to prosthesis prescription. Multiple logistic and linear regression was used to control for potential confounders and identify potential effect modification. RESULTS: 2,862 individuals met study criteria, with 1690 (60%) prescribed a qualifying prosthesis. Men were more likely to receive a prosthesis prescription than women (59% versus 45%, respectively; p = 0.03). This difference was observed primarily among those with a diagnosis of major depressive disorder. In this subgroup, the odds of men receiving a prosthesis over women was over 3 times (adjusted odds ratio = 3.3; 95% Confidence Interval, 1.5, 7.4). Men had a mean shorter time to prescription compared to women (112 ± 72 versus 136 ± 79 days, respectively, p = 0.08).Depression in women negatively impacts their prosthesis prescription rates and time to prescription compared to men. This disparity may have significant impacts on future function and quality of life.Implications for RehabilitationThis study found that men more commonly received a prosthesis prescription and received it earlier than women.This disparity was most extreme among women who had been diagnosed with major depressive disorder.Providers should identify at risk patients early and consider targeted interventions to address depression during the preoperative and immediate postoperative phases.Future research should continue to work to identify gender-specific needs that exacerbate disparity.

PROClass: The Development and Validation of a Novel Prosthetic Component Sophistication Classification System.

Objective: To develop a lower limb prosthesis (LLP) sophistication classification system that categorizes prosthetic component prescriptions into "basic," "intermediate," and "advanced" and assess its content validity, reliability, and accuracy. Design: Classification development and validation study. Setting: The Veterans Affairs (VA) Corporate Data Warehouse database and National Prosthetics Patient Database were used to identify patients undergoing their first amputation at the transtibial or transfemoral level due to diabetes or peripheral artery disease and to identify the associated codes for each LLP. Participants: An expert panel of 6 nationally recognized certified prosthetists, a national expert in VA prosthetics data and coding, a physical medicine and rehabilitation physician, and an epidemiologist developed an LLP classification system (PROClass) using 30 transfemoral and transtibial lower limb amputees. Main Outcome Measures: The expert panel reviewed 20 consecutive participants meeting study criteria for the development of the PROClass system and a subsequent 30 consecutive cases for assessing the inter- and intra-rater reliability and accuracy. Results: The interrater and intrarater reliability was almost perfect with Gwet's AC1 values ranging from .82 to .96 for both expert panel members and research assistants. The accuracy of the research assistant's classifications to the "criterion standard" was excellent with Gwet's AC1 values ranging between .75 and .92. Conclusions: PROClass is a pragmatic, reliable, and accurate prosthetic classification system with strong face validity that will enable the classification of prosthetic components used for large data set research aimed at evaluating important clinical questions such as the effects of sophistication on patient outcomes.

Comparing Patient and Provider Priorities Around Amputation Level Outcomes Using Multiple Criteria Decision Analysis.

BACKGROUND: Patients with chronic limb threatening ischemia may require a transmetatarsal amputation (TMA) or a transtibial amputation. When making an amputation-level decision, these patients face a tradeoff-a TMA preserves more limb and may provide better mobility but has a lower probability of primary wound healing and may therefore result in additional same or higher level amputation surgeries with an associated negative impact on function. Understanding differences in how patients and providers prioritize these tradeoffs and other outcomes may enhance shared decision-making. OBJECTIVES: Compare patient priorities with provider perceptions of patient priorities using Multiple Criteria Decision Analysis (MCDA). METHODS: The MCDA Analytic Hierarchy Process was chosen due to its low cognitive burden and ease of implementation. We included 5 criteria (outcomes): ability to walk, healing after amputation surgery, rehabilitation program intensity, limb length, and ease of use of prosthetic/orthotic device. A national sample of dysvascular lower-limb amputees and providers were recruited from the Veterans Health Administration with the MCDA administered online to providers and telephonically to patients. RESULTS: Twenty-six dysvascular amputees and 38 providers participated. Fifty percent of patients had undergone a TMA; 50%, a transtibial amputation. When compared to providers, patients placed higher value on TMA (72% vs. 63%). Patient versus provider priorities were ability to walk (47% vs. 42%), healing (18% vs. 28%), ease of prosthesis use (17% vs. 13%), limb length (11% vs. 13%), and then rehabilitation intensity (7% vs. 6%). LIMITATIONS: Our sample may not generalize to other populations. CONCLUSIONS: Provider perceptions aligned with patient values on amputation level but varied around the importance of each outcome. IMPLICATIONS: These findings illuminate some differences between patients' values and provider perceptions of patient values, suggesting a role for shared decision-making. Embedding this MCDA framework into a future decision aid may facilitate these discussions.

Perceived shared decision-making among patients undergoing lower-limb amputation and their care teams: A qualitative study.

BACKGROUND: Shared decision-making (SDM) is increasingly advocated in the care of vascular surgery patients. The goal of this investigation was to gain a greater understanding of the patient and provider experience of SDM during clinical decision-making around the need for lower-extremity amputation and amputation level related to chronic limb-threatening ischemia (CLTI) in the Veterans Health Administration. METHODS: Semistructured interviews in male Veterans with CLTI, vascular surgeons, physical medicine and rehabilitation physicians, and podiatric surgeons. Interviews were analyzed using team-based content analysis to identify themes related to amputation-level decisions. RESULTS: We interviewed 22 patients and 21 surgeons and physicians and identified 4 themes related to SDM: (1) providers recognize the importance of incorporating patient preferences into amputation-level decisions and strive to do so; (2) patients do not perceive that they are included as equal partners in decisions around amputation or amputation level; (3) providers perceive several obstacles to including patients in amputation level decisions; and (4) patients describe facilitators to their involvement in SDM. CONCLUSIONS: Despite the recognized importance SDM in amputation decision-making, patients often perceived that their opinion was not solicited. This may result from provider perception of significant challenges to SDM posed by the clinical context of amputation. Patients identified key features that might enhance SDM including presentation of clear, concise information, and the importance of communicating concern during the discussion. These findings point to gaps in the provision of patient-centric care through SDM discussions at the time of amputation.

Differences in Prosthetic Prescription Between Men and Women Veterans After Transtibial or Transfemoral Lower-Extremity Amputation: A Longitudinal Cohort Study (2005-2018).

OBJECTIVE: To evaluate whether prosthetic prescription differed by gender and the extent to which differences were mediated by measured factors. DESIGN: Retrospective longitudinal cohort study using data from Veterans Health Administration (VHA) administrative databases. SETTING: VHA patients throughout the United States. PARTICIPANTS: The sample included 20,889 men and 324 women who had an incident transtibial or transfemoral amputation between 2005 and 2018. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Time to prosthetic prescription (up to 1 year). We used parametric survival analysis (an accelerated failure time model) to assess gender differences. We estimated mediation effects of amputation level, pain comorbidity burden, medical comorbidities, depression, and marital status on time to prescription. RESULTS: In the 1 year after amputation, the proportion of women (54.3%) and men (55.7%) prescribed a prosthesis was similar. However, after we controlled for age, race, ethnicity, enrollment priority, VHA region, and service-connected disability, the time to prosthetic prescription was significantly faster among men compared with women (acceleration factor=0.73; 95% confidence interval, 0.61-0.87). The difference in time to prosthetic prescription between men and women was significantly mediated by amputation level (23%), pain comorbidity burden (-14%), and marital status (5%) but not medical comorbidities or depression. CONCLUSIONS: Although the proportion of patients with prosthetic prescription at 1-year postamputation was similar between men and women, women received prosthetic prescriptions more slowly than men, suggesting that more work is needed to understand barriers to timely prosthetic prescriptions among women, and how to intervene to reduce those barriers.

Mortality Conversations Between Male Veterans and Their Providers Prior to Dysvascular Lower Extremity Amputation.

BACKGROUND: Among patients facing lower extremity amputation due to dysvascular disease, the mortality risk is very high. Given this, as well as the importance of a patient-centered approach to medical care, informing patients about their possible risk of dying may be important during preoperative shared decision-making. The goal of this investigation was to gain an understanding of patient and provider experiences discussing mortality within the context of amputation within the Veterans Health Administration. METHODS: Semistructured interviews were performed with Veterans with peripheral arterial disease and/or diabetes, vascular and podiatric surgeons, and physical medicine and rehabilitation physicians. Interviews were analyzed using team-based content analysis to identify themes related to amputation-level decisions. RESULTS: We interviewed 22 patients and 21 surgeons and physicians and identified 3 themes related to conversations around mortality: (1) both patients and providers report that mortality conversations are not common prior to amputation; (2) while most providers find value in mortality conversations, some express concerns around engaging in these discussions with patients; and (3) some patients perceive mortality conversations as unnecessary, but many are open to engaging in the conversation. CONCLUSIONS: Providers may benefit from introducing the topic with patients, including providing the context for why mortality conversations may be valuable, with the understanding that patients can always decline to participate should they not be interested or comfortable discussing this issue.

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.

Full body musculoskeletal model for simulations of gait in persons with transtibial amputation.

This paper describes the development, properties, and evaluation of a musculoskeletal model that reflects the anatomical and prosthetic properties of a transtibial amputee using OpenSim. Average passive prosthesis properties were used to develop CAD models of a socket, pylon, and foot to replace the lower leg. Additional degrees of freedom (DOF) were included in each joint of the prosthesis for potential use in a range of research areas, such as socket torque and socket pistoning. The ankle has three DOFs to provide further generality to the model. Seven transtibial amputee subjects were recruited for this study. 3 D motion capture, ground reaction force, and electromyographic (EMG) data were collected while participants wore their prescribed prosthesis, and then a passive prototype prosthesis instrumented with a 6-DOF load cell in series with the pylon. The model's estimates of the ankle, knee, and hip kinematics comparable to previous studies. The load cell provided an independent experimental measure of ankle joint torque, which was compared to inverse dynamics results from the model and showed a 7.7% mean absolute error. EMG data and muscle outputs from OpenSim's Static Optimization tool were qualitatively compared and showed reasonable agreement. Further improvements to the muscle characteristics or prosthesis-specific foot models may be necessary to better characterize individual amputee gait. The model is open-source and available at (https://simtk.org/projects/biartprosthesis) for other researchers to use to advance our understanding and amputee gait and assist with the development of new lower limb prostheses.

AMPREDICT PROsthetics-Predicting Prosthesis Mobility to Aid in Prosthetic Prescription and Rehabilitation Planning.

OBJECTIVE: To develop and validate a patient-specific multivariable prediction model that uses variables readily available in the electronic medical record to predict 12-month mobility at the time of initial post-amputation prosthetic prescription. The prediction model is designed for patients who have undergone their initial transtibial (TT) or transfemoral (TF) amputation because of complications of diabetes and/or peripheral artery disease. DESIGN: Multi-methodology cohort study that identified patients retrospectively through a large Veteran's Affairs (VA) dataset then prospectively collected their patient-reported mobility. SETTING: The VA Corporate Data Warehouse, the National Prosthetics Patient Database, participant mailings, and phone calls. PARTICIPANTS: Three-hundred fifty-seven veterans who underwent an incident dysvascular TT or TF amputation and received a qualifying lower limb prosthesis between March 1, 2018, and November 30, 2020 (N=357). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The Amputee Single Item Mobility Measure (AMPSIMM) was divided into a 4-category outcome to predict wheelchair mobility (0-2), and household (3), basic community (4), or advanced community ambulation (5-6). RESULTS: Multinomial logistic lasso regression, a machine learning methodology designed to select variables that most contribute to prediction while controlling for overfitting, led to a final model including 23 predictors of the 4-category AMPSIMM outcome that effectively discriminates household ambulation from basic community ambulation and from advanced community ambulation-levels of key clinical importance when estimating future prosthetic demands. The overall model performance was modest as it did not discriminate wheelchair from household mobility as effectively. CONCLUSIONS: The AMPREDICT PROsthetics model can assist providers in estimating individual patients' future mobility at the time of prosthetic prescription, thereby aiding in the formulation of appropriate mobility goals, as well as facilitating the prescription of a prosthetic device that is most appropriate for anticipated functional goals.

The Development and Pilot Study of a Multiple Criteria Decision Analysis (MCDA) to Compare Patient and Provider Priorities around Amputation-Level Outcomes.

Background. Patients with chronic limb-threatening ischemia who are facing a lower-limb amputation often require a transmetatarsal amputation (TMA) or a transtibial amputation (TTA). A TMA preserves more of the patient's limb and may provide better mobility but has a lower probability of primary wound healing relative to a TTA and may result in additional amputation surgeries. Understanding the differences in how patients and providers prioritize key outcomes may enhance the amputation decisional process. Purpose. To develop and pilot test a multiple criteria decision analysis (MCDA) tool to elicit patient values around amputation-level selection and compare those with provider perceptions of patient values. Methods. We conducted literature reviews to identify and measure the performance of criteria important to patients. Because the quantitative literature was sparse, we developed a Sheffield elicitation framework exercise to elicit criteria performance from subject matter experts. We piloted our MCDA among patients and providers to understand tool acceptability and preliminarily assess differences in patient and provider priorities. Results. Five criteria of importance were identified: ability to walk, healing after amputation surgery, rehabilitation intensity, limb length, and prosthetic/orthotic device ease. Patients and providers successfully completed the MCDA and identified challenges in doing so. We propose potential solutions to these challenges. The results of the pilot test suggest differences in patient and provider outcome priorities. Limitations. The pilot test study enrolled a small sample of providers and patients. Conclusions. We successfully implemented the pilot study to patients and providers, received helpful feedback, and identified solutions to improve the tool. Implications. Once modified, our MCDA tool will be suitable for wider rollout. Highlights: Patients and providers have successfully completed our MCDA, and patients feel the MCDA may be useful in clinical practice.We encountered several methodologic challenges and identified approaches to ease participant burden.When data are sparse, using the Sheffield elicitation framework is helpful in creating a performance matrix, although patients relied largely on their amputation experiences to complete the exercise. Blinding the alternatives may help patients better understand the process.

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

Introduction: The most suitable elevated vacuum (EV) pressure may differ for each individual prosthesis user depending on suspension needs, socket fit, prosthetic components, and health. Mechanical and physiological effects of EV were evaluated in an effort to determine the optimal vacuum pressure for three individuals. Methods: Instrumented EV sockets were created based on the participants' regular EV sockets. Inductive distance sensors were embedded into the wall of the socket at select locations to measure limb movement relative to the socket. Each participant conducted an activity protocol while limb movement, limb fluid volume, and user-reported comfort were measured at various socket vacuum pressure settings. Results: Increased socket vacuum pressure resulted in reduced limb-socket displacement for each participant; however, 81-93% of limb movement was eliminated by a vacuum pressure setting of 12 (approximately -9 inHg). Relative limb-socket displacement by sensor location varied for each participant, suggesting distinct differences related to socket fit or residual limb tissue content. The rate of limb fluid volume change and the change in socket comfort did not consistently differ with socket vacuum pressure, suggesting a more complex relationship unique to each individual. Conclusions: Practitioners may use individual responses to optimize socket vacuum pressure settings, balancing mechanical and physiological effects of EV for improved clinical outcomes.

Voices of Women Veterans with Lower Limb Prostheses: a Qualitative Study.

BACKGROUND: Women Veterans with amputation are a group with unique needs whose numbers have grown over the last 5 years, accounting for nearly 3% of all Veterans with amputation in 2019. Although identified as a national priority by the Veterans Health Administration, the needs of this population have remained largely underrepresented in amputation research. OBJECTIVE: To describe the experiences of women Veterans with lower extremity amputation (LEA) related to prosthetic care provision and devices. DESIGN: National qualitative study using semi-structured individual interviews. PARTICIPANTS: Thirty women Veterans with LEA who had been prescribed a prosthesis at least 12 months prior. APPROACH: Inductive content analysis. KEY RESULTS: Four key themes emerged: (1) a sense of "feeling invisible" and lacking a connection with other women Veterans with amputation; (2) the desire for prosthetic devices that meet their biological and social needs; (3) the need for individualized assessment and a prosthetic limb prescription process that is tailored to women Veterans; the current process was often perceived as biased and either dismissive of women's concerns or failing to adequately solicit them; and (4) the desire for prosthetists who listen to and understand women's needs. CONCLUSIONS: Women Veterans with LEA articulated themes reminiscent of those previously reported by male Veterans with LEA, such as the importance of prostheses and the central role of the provider-patient relationship. However, they also articulated unique needs that could translate into specific strategies to improve prosthetic care, such as integrating formal opportunities for social support and peer interaction for women Veterans with LEA, advocating for administrative changes and research efforts to expand available prosthetic component options, and ensuring that clinical interactions are gender-sensitive and free of bias.

Risks and Risk Factors for Contralateral Amputation in Patients who have Undergone Amputation for Chronic Limb Threatening Ischaemia.

OBJECTIVE: The aim of this study was to determine the cumulative incidence of, and the risk factors associated with, contralateral amputation in patients with chronic limb threatening ischaemia (CLTI). METHODS: This was a retrospective cohort study of patients with incident unilateral transmetatarsal (TM), transtibial (TT), or transfemoral (TF) amputation secondary to CLTI, identified from the National Veterans Affairs Surgical Quality Improvement Program database (2004 - 2014). Thirteen potential pre-operative risk factors for contralateral amputation were considered. A competing risk analysis to estimate the cumulative incidence of contralateral amputation was performed using a Fine-Gray subdistribution hazard model. The effect of risk factors on contralateral amputation was estimated by computing subdistribution hazard ratios (sub-HR) with 95% confidence intervals (CI). RESULTS: From the database, 7 360 patients met the inclusion criteria. The contralateral amputation risk was 7.7% and was greatest in those who underwent a TF amputation (9.7%), followed by TT (7.4%) and TM amputation (6.6%) (p < .001). Among the 588 contralateral amputations, 50% were at the TF level, 34% at the TT level, and 16% at the TM level. The adjusted risk of contralateral amputation was greater in those who underwent an incident TF amputation or were Black or Hispanic. The factor that contributed to risk of contralateral amputation to the greatest extent was dialysis (sub-HR, 2.3; 95% CI 1.7 - 3.0; p < .001) while those who were obese (compared with underweight) were at lowest risk (0.67; 95% CI 0.46 - 0.97; p = .030). CONCLUSION: The one year risk of contralateral amputation in patients with CLTI is related to incident amputation level, medical comorbidities, correlates with race/ethnicity, and body mass index at the time of the incident amputation. The identified risk factors are largely not modifiable; however, they can be used to help identify populations at elevated risk.

Understanding the experience of veterans who require lower limb amputation in the veterans health administration.

PURPOSE: There is limited qualitative research on the experience of patients undergoing lower limb amputation due to chronic limb threatening ischemia (CLTI) and their participation in amputation-level decisions. This study was performed to understand patient lived experiences related to amputation and patient involvement in shared decision making. MATERIALS AND METHODS: Phenomenological interviews were conducted with Veterans 6-12 months post transtibial or transmetatarsal amputation due to CLTI. Interviews were read and summarized by two analysts who discussed the contents of each interview and relationships between interviews to identify emergent, cross-cutting elements of patient experience. RESULTS: Twelve patients were interviewed between March and August 2019. Three cross cutting elements of patient lived experience and participation in shared decision making were identified: 1) Lacking a sense of decision making; 2) Actively working towards recovery as response to a perceived loss of independence; and 3) Experiencing amputation as a Veteran. CONCLUSIONS: Patients did not report a high level of involvement in shared decision making about their amputation or amputation level. Understanding patient experiences and priorities is crucial to supporting shared decision making for Veterans with amputation due to CLTI.

Racial and ethnic amputation level disparities in veterans undergoing incident dysvascular lower extremity amputation.

BACKGROUND: The choice of incident amputation level can have a profound effect on clinical outcomes. Amputations at the transmetatarsal (TM) or transtibial (TT) levels result in greater preservation of function and mobility, whereas transfemoral (TF) amputations typically result in a greater adverse impact. Prior investigations have explored racial/ethnic and regional variation in incident amputation level. This study overcomes some of the methodological limitations seen in prior research through the use of a large national, multiyear veteran sample and by including only those who have undergone an incident amputation. OBJECTIVES: (1) Determine if there are national/regional differences in the frequency of incident TF amputation compared with TM and TT amputation, (2) Determine if race/ethnicity and geographic region are associated with incident TF amputation level, and (3) Determine if racial/ethnic disparities of incident TF amputation differ by the presence of diabetes or prior revascularization. DESIGN: Retrospective cohort study of veterans undergoing an incident dysvascular lower extremity amputation. SETTING: One hundred ten Veterans Affairs (VA) Medical Centers. PARTICIPANTS: Seven thousand two hundred ninety-six Veterans undergoing incident unilateral dysvascular lower extremity amputation identified in the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database (2005-2014). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Incident amputation level. RESULTS: The White, Black, and Hispanic risk for an incident TF amputation was 31% (n = 1356), 35% (n = 810), and 46% (n = 293), respectively. In the Continental region, Blacks who had not had a prior revascularization were more likely to undergo a TF amputation compared to Whites both with and without diabetes (odds ratio [OR] = 1.4; 95% confidence interval [CI], 1.1, 1.9 and OR = 1.5; 95% CI, 1.1, 2.1, respectively). In the Southeast region, Hispanics compared with Whites were at increased odds of undergoing a TF amputation, irrespective of a diabetes or a prior revascularization (ORs ≥ 2.9). CONCLUSIONS: Racial and ethnic disparities exist in choice of proximal compared with distal amputation in specific VA geographic regions.

Evaluation of a quasi-passive biarticular prosthesis to replicate gastrocnemius function in transtibial amputee gait.

Lower limb amputees experience gait impairments, in part due to limitations of prosthetic limbs and the lack of a functioning biarticular gastrocnemius (GAS) muscle. Energy storing prosthetic feet restore the function of the soleus, but not GAS. We propose a transtibial prosthesis that implements a spring mechanism to replicate the GAS. A prototype Biarticular Prosthesis (BP) was tested on seven participants with unilateral transtibial amputation. Participants walked on an instrumented treadmill with motion capture, first using their prescribed prosthesis, then with the BP in four different spring stiffness conditions. A custom OpenSim musculoskeletal model, including the BP, was used to estimate kinematics, joint torques, and muscle forces. Kinematic symmetry was evaluated by comparing the amputated and intact angles of the ankle, knee, and hip. The BP knee and ankle torques were compared to the intact GAS. Finally, work done by the BP spring was calculated at the ankle and knee. There were no significant differences between conditions in kinematic symmetry, indicating that the BP performs similarly to prescribed prostheses. When comparing the BP torques to intact GAS, higher spring stiffness better approximated peak GAS torques, but those peaks occurred earlier in the gait cycle. The BP spring did positive work on the knee joint and negative work on the ankle joint, and this work increased as BP spring stiffness increased. The BP has the potential to improve amputee gait compensations associated with the lack of biarticular GAS function, which may reduce their walking effort and improve quality of life.

The Development and Usability of the AMPREDICT Decision Support Tool: A Mixed Methods Study.

OBJECTIVE: Amputation level decision making in patients with chronic limb threatening ischaemia is challenging. Currently, evidence relies on published average population risks rather than individual patient risks. The result is significant variation in the distribution of amputation levels across health systems, geographical regions, and time. Clinical decision support has been shown to enhance decision making, especially complex decision making. The goal of this study was to translate the previously validated AMPREDICT prediction models by developing and testing the usability of the AMPREDICT Decision Support Tool (DST), a novel, web based, clinical DST that calculates individual one year post-operative risk of death, re-amputation, and probability of achieving independent mobility by amputation level. METHODS: A mixed methods approach was used. Previously validated prediction models were translated into a web based DST with additional content and format developed by an expert panel. Tool usability was assessed using the Post-Study System Usability Questionnaire (PSSUQ; a 16 item scale with scores ranging from 1 to 7, where lower scores indicate greater usability) by 10 clinician end users from diverse specialties, sex, geography, and clinical experience. Think aloud, semi-structured, qualitative interviews evaluated the AMPREDICT DST's look and feel, user friendliness, readability, functionality, and potential implementation challenges. RESULTS: The PSSUQ overall and subscale scores were favourable, with a mean overall total score of 1.57 (standard deviation [SD] 0.69) and a range from 1.00 to 3.21. The potential clinical utility of the DST included (1) assistance in counselling patients on amputation level decisions, (2) setting outcome expectations, and (3) use as a tool in the academic environment to facilitate understanding of factors that contribute to various outcome risks. CONCLUSION: After extensive iterative development and testing, the AMPREDICT DST was found to demonstrate strong usability characteristics and clinical relevance. Further evaluation will benefit from integration into an electronic health record with assessment of its impact on physician and patient shared amputation level decision making.