Falls perceived as significant by lower limb prosthesis users are generally associated with fall consequences rather than circumstances.

PURPOSE: To determine if falls perceived as significant by lower limb prosthesis (LLP) users were associated with fall circumstances and/or consequences. MATERIALS AND METHODS: The circumstances and consequences of LLP users' most significant fall in the past 12-months were collected using the Lower Limb Prosthesis User Fall Event Survey. Participants rated fall significance from 0 (not significant) to 10 (extremely significant), which was then dichotomized into "low" and "high". Binary logistic regression was used to assess associations between fall significance and fall circumstances and consequences. RESULTS: Ninety-eight participants were included in the analysis. Five fall consequences were associated with greater significance: major injury (OR = 26.7, 95% CI: 1.6-459.6, p = 0.024), need to seek medical treatment (OR = 19.0, 95% CI: 1.1-329.8, p = 0.043), or allied-health treatment (OR = 18.2, 95% CI: 2.3-142.4, p = 0.006), decreased balance confidence (OR = 10.9, 95% CI: 2.4-49.3, p = 0.002), and increased fear of falling (OR = 7.5, 95% CI: 2.4-23.8, p = 0.001), compared to two fall circumstances: impact to the arm (OR = 5.0, 95% CI: 2.0-12.1, p = 0.001), and impact to the face, head, or neck (OR = 9.7, 95% CI: 1.2-77.4, p = 0.032). CONCLUSIONS: Significant falls were generally more associated with fall consequence than fall circumstances.

Falls remain common, injurious, costly, and socially isolating events for lower limb prosthesis (LLP) users.Falls perceived as most significant by LLP users were associated with injury, reduced balance confidence, and increased fear-of-falling.Studying falls perceived by LLP users as significant may help reduce falls that matter most to LLP users.

Use of standardized outcome measures for people with lower-limb amputation: A survey of prosthetic practitioners in Canada.

BACKGROUND: Outcome measures (OMs) are useful tools; however, clinicians may find implementing them into clinical practice challenging. OBJECTIVES: To characterize Canadian prosthetists' use of OMs for people with lower-limb amputation, including motivations for use, comfort selecting OMs, resources available for administration, and barriers to implementation. METHODS: A cross-sectional study was conducted between March and July 2021. Orthotics Prosthetics Canada sent Canadian prosthetists an invitation to take the online survey. RESULTS: Forty-nine Certified Prosthetists completed the survey. Only 16% of participants reported that they were expected to use OMs. Participants reported being more comfortable administering performance-based OMs than self-report surveys. More than two-thirds of participants agreed that OMs "can be administered with knowledge they have" and are "within their scope of practice." However, less than 25% agreed that OMs are "administered in a standardized way in the profession," and less than 40% indicated they are "easy to make part of my routine." Participants reported they generally have time and space to do OMs, but there was no agreed-on reason to use them. CONCLUSIONS: Use of OMs among Canadian prosthetists seems to be low relative to prosthetists in the United States. Education, financial incentives, or changes to professional expectations are likely needed to increase routine OM use. Efforts to improve the standardization of OM administration and ease the incorporation of OMs into routine practice may also increase use. Canadian prosthetists may elevate their standards of clinical practice and better understand the impact of prosthetic treatments on their patients by more routinely using OMs.

The development of rating scales to evaluate experiential prosthetic foot preference for people with lower limb amputation.

BACKGROUND: Selection of a foot is an important aspect of prosthetic prescription and vital to maximizing mobility and functional goals after lower limb amputation. Development of a standardized approach to soliciting user experiential preferences is needed to improve evaluation and comparison of prosthetic feet. OBJECTIVE: To develop rating scales to assess prosthetic foot preference and to evaluate use of these scales in people with transtibial amputation after trialing different prosthetic feet. DESIGN: Participant-blinded, repeated measures crossover trial. SETTING: Veterans Affairs and Department of Defense Medical Centers, laboratory setting. PARTICIPANTS: Seventy-two male prosthesis users with unilateral transtibial amputation started, and 68 participants completed this study. INTERVENTIONS: Participants trialed three mobility-level appropriate commercial prosthetic feet briefly in the laboratory. MAIN OUTCOME MEASURES: "Activity-specific" rating scales were developed to assess participants' ability with a given prosthetic foot to perform typical mobility activities (eg, walking at different speeds, on inclines, and stairs) and "global" scales to rate overall perceived energy required to walk, satisfaction, and willingness to regularly use the prosthetic foot. Foot preference was determined by comparing the rating scale scores, after laboratory testing. RESULTS: The greatest within-participant differences in scores among feet were observed in the "incline" activity, where 57% ± 6% of participants reported 2+ point differences. There was a significant association (p < .05) between all "activity-specific" rating scores (except standing) and each "global" rating score. CONCLUSIONS: The standardized rating scales developed in this study could be used to assess prosthetic foot preference in both the research and clinical settings to guide prosthetic foot prescription for people with lower limb amputation capable of a range of mobility levels.

Development and initial validation of the Orthotic Patient-Reported Outcomes-Mobility (OPRO-M): An item bank for evaluating mobility of people who use lower-limb orthoses.

Lower limb orthoses (LLOs) are externally-applied leg braces that are designed to improve or maintain mobility in people with a variety of health conditions that affect lower limb function. Clinicians and researchers are therefore often motivated to measure LLO users' mobility to select or assess the effectiveness of these devices. Patient-reported outcome measures (PROMs) can provide insights into important aspects of a LLO user's mobility for these purposes. However, few PROMs are available to measure mobility of LLO users. Those few that exist have issues that may limit their clinical or scientific utility. The objective of this study was to create a population-specific item bank for measuring mobility of LLO users. Previously-developed candidate items were administered in a cross-sectional study to a large national sample of LLO users. Responses from study participants (n = 1036) were calibrated to a graded response statistical model using Item Response Theory methods. A set of 39 items was found to be unidimensional, locally independent, and function without bias due to characteristics unrelated to mobility. The set of final calibrated items, termed the Orthotic Patient-Reported Outcomes-Mobility (OPRO-M) item bank, was evaluated for initial evidence of convergent, divergent, and known groups construct validity. OPRO-M was strongly correlated with existing PROMs designed to measure aspects of physical function. Conversely, OPRO-M was weakly correlated with PROMs that measured unrelated constructs, like sleep disturbance and depression. OPRO-M also showed an ability to differentiate groups with expected mobility differences. Two fixed-length short forms were created from the OPRO-M item bank. Items on the short forms were selected based on statistical and clinical criteria. Collectively, results from this study indicate that OPRO-M can effectively measure mobility of LLO users, and OPRO-M short forms can now be recommended for use in routine clinical practice and research studies.

Perceptions of prosthetic attention among lower limb prosthesis users: a focus group study.

PURPOSE: Use of a lower limb prosthesis generally requires increased cognitive effort to compensate for missing motor and sensory inputs. This study sought to examine how lower limb prosthesis users perceive paying attention to their prosthesis(es) in daily life. MATERIALS AND METHODS: Focus groups with lower limb prosthesis users were conducted virtually using semi-structured questions. Verbatim transcripts were excerpted, coded, and reconciled. Inductive thematic analysis was undertaken to identify experiences shared by participants. RESULTS: Five themes emerged from five focus groups conducted with thirty individuals: Paying attention to my prosthesis is just what I have to do; I pay attention to how my prosthetic socket fits and feels every day; I pay attention because I don't want to fall; I pay attention because I have to learn to do things in a new way; and If I can trust that my prosthesis will do what I want, I can pay less attention to it. CONCLUSIONS: Prosthetic attention, including both background and foreground attention, is a shared experience among lower limb prosthesis users. The amount and frequency of prosthetic attention fluctuates throughout the day and changes over time. Measuring attention could inform the evaluation and prescription of technology intended to reduce cognitive effort.

Walking or performing mobility tasks with a prosthesis requires increased attention and may limit the cognitive resources available for other important activities.Lower limb prosthesis users report paying attention to their prosthesis(ses) to avoid falling, to maintain the fit of their prosthetic socket, and to learn to complete mobility tasks with a prosthesis.Clinicians should discuss prosthetic attention with new prosthesis users and explain how it is expected to decrease over time.Prosthetic technology may affect prosthetic attention but development of a measure to assess prosthetic attention is needed to accurately evaluate this relationship.

Categorization and recommendations for outcome measures for lower limb absence by an expert panel.

BACKGROUND: Understanding the psychometric strengths and limitations of outcome measures for use with people with lower limb absence (LLA) is important for selecting measures suited to evaluating patient outcomes, answering clinical and research questions, and informing health care policy. The aim of this project was to review the current psychometric evidence on outcome measures in people with LLA to determine which measures should be included in a stakeholder consensus process. METHODS: An expert panel was assembled, and a 3-stage review process was used to categorize outcome measures identified in a systematic literature review into 3 distinct categories (recommended for measures with better than adequate psychometric properties; recommended with qualification; and unable to recommend). Panelists were asked to individually categorize measures based on results of a systematic review of identified measures' psychometric properties. Each measure's final categorization was based on ≥70% agreement by all panelists. RESULTS: No outcome measure attained the ≥70% consensus threshold needed to achieve a rating of "recommend." Hence, panelists suggested combining "recommend" and "recommend with qualifications" into a single category of "recommend with qualifications." Using this approach, consensus was reached for 59 of 60 measures. Consensus could not be reached on 1 outcome measure (socket comfort score). Thirty-six outcome measures were categorized as "unable to recommend" based on available evidence; however, 23 (12 patient-reported measures and 11 performance-based measures) demonstrated adequate psychometric properties in LLA samples and were thus rated as "recommend with qualification" by the expert panel. The panel of experts were able to recommend 23 measures for inclusion in the subsequent stakeholder review. A key strength of this process was bringing together international researchers with extensive experience in developing and/or using LLA outcome measures who could assist in identifying psychometrically sound measures to include in a subsequent stakeholder consensus process. CONCLUSION: The above categorizations represent the current state of psychometric evidence on outcome measures for people with LLA and hence may change over time as additional research becomes available. The results will be used to achieve wider consensus from clinicians, health policymakers, health clinic managers, researchers, and end users (i.e., individuals with LLA) on outcome measures for the International Society of Prosthetics and Orthotics lower limb Consensus Outcome Measures for Prosthetic and Amputation ServiceS.

Effects of high-profile crossover feet on gait biomechanics in 2 individuals with Syme amputation.

BACKGROUND: Prosthetic treatment options for people with ankle disarticulation (i.e., Syme amputation) are limited. Prosthetic feet designed for people with Syme amputation are often low profile to accommodate build-height restrictions, resulting in decreased energy return during gait. High-profile crossover feet that attach to the posterior proximal aspect of the prosthetic socket can bypass these restrictions and may promote a more physiologic gait pattern. OBJECTIVES: To compare level-ground gait biomechanics and patient-reported outcomes between crossover and traditional energy-storing feet in people with Syme amputation. STUDY DESIGN: Within-participant pilot study. METHODS: Both participants were fit with energy-storing and crossover feet and were randomized to the order they used the feet. Participants used each foot for 2 weeks before assessment. Step length symmetry, prosthetic ankle range of motion, prosthetic-side energy return, and peak sound-side loading were determined from motion capture data obtained in a laboratory. Mobility and balance confidence were measured using standardized patient-reported outcome measures. Foot preference was assessed with an ad hoc survey. RESULTS: Two participants with Syme amputations completed the study. Prosthetic ankle peak dorsiflexion and push-off power increased with the crossover foot compared with the energy-storing foot for both participants. Both participants reported an overall preference of the crossover foot. Changes in patient-reported outcomes did not exceed published minimum detectable change values. CONCLUSION: Crossover feet increased prosthetic ankle range of motion and energy return compared with traditional energy-storing feet in this pilot investigation of 2 participants. Crossover feet seem to promote physiologic gait and may be a promising alternative to traditional low-profile feet for people with Syme amputation.

Design and testing of a simple quick connect for a prosthetic liner tether.

BACKGROUND: A limitation of tether lanyards is that fastening and unfastening the tether from the liner, which needs to be performed to clean or replace the liner, is difficult for some users. OBJECTIVE: The purpose of this research was to create a quick connect that allows users to easily attach and detach the tether from the liner. STUDY DESIGN: Mechanical testing and pilot study. METHODS: A slide-and-lock mechanism was used. To operate the quick connect, the prosthesis user turns open the lock, slides it onto a short pin extending from the liner, and releases the mechanism, causing it to spring back to the locked position. RESULTS: Mechanical tests demonstrated that the system well-tolerated tensile loads of 25,000 cycles at 100 N and single cycles at 350 N. Five transtibial users trialed the system and took between 2 and 30 s to fasten and unfasten the quick connect. They found the quick connect intuitive to use, secure, relatively quiet, and stable. However, they preferred their traditional pin lock over the quick connect system, mainly because the quick connect required a multistep procedure (twist-align-slide) that they considered more complex than operating the locking pin to which they were accustomed. CONCLUSIONS: In its current form, the quick connect is likely to be used by limited community ambulators who struggle with the pin lock donning procedure. It also has potential use with powered tethers that use a motor to adjust tether length.

Short partial doffs of release/relock sockets may effectively stabilize limb fluid volume in prosthesis users with transtibial amputation.

BACKGROUND: A challenge often faced by people with lower extremity amputation is management of prosthetic socket fit due to changes in fluid volume within their residual limb. Prior research suggests that intermittently doffing the prosthetic socket may help stabilize daily residual limb fluid volume. METHODS: To assess the effects of partial doff duration on residual limb fluid volume retention, participants with transtibial amputation were tested by walking on a treadmill in a controlled, laboratory setting under three conditions. An automated system to release the locking pin and enlarge the socket was used to produce the partial doffing. Percent limb fluid volume changes after partial doffing for 4 min (Short Rest) and for 10 min (Long Rest) were compared with no partial doffing (No Release). Limb fluid volume was monitored using bioimpedance analysis. FINDINGS: Mean percent fluid volume changes in the posterior region were  -1.2% for No Release, 2.7% for Short Rest, and 1.0% for Long Rest. Short and Long Rests had larger increases than No Release (P = 0.005 and 0.03, respectively); Short and Long Rests were not statistically different (P = 0.10). Eight of the thirteen participants experienced a higher percent fluid volume gain for both release protocols while four experienced a higher percent fluid volume gain for only one release protocol. INTERPRETATION: A partial doff duration as short as 4 min may be an effective strategy to stabilize limb fluid volume in prosthesis users with transtibial amputation. Trials in at-home settings should be pursued.

Learning Health Systems Research Competencies: A Survey of the Rehabilitation Research Community.

OBJECTIVE: The Learning Health Systems Rehabilitation Research Network (LeaRRn), an NIH-funded rehabilitation research resource center, aims to advance the research capacity of learning health systems (LHSs) within the rehabilitation community. A needs assessment survey was administered to inform development of educational resources. METHODS: The online survey included 55 items addressing interest in and knowledge of 33 LHS research core competencies in 7 domains and additional items on respondent characteristics. Recruitment targeting rehabilitation researchers and health system collaborators was conducted by LeaRRn, LeaRRn health system partners, rehabilitation professional organizations, and research university program directors using email, listservs, and social media announcements. RESULTS: Of the 650 people who initiated the survey, 410 respondents constituted the study sample. Respondents indicated interest in LHS research and responded to at least 1 competency item and/or demographic question. Two-thirds of the study sample had doctoral research degrees, and one-third reported research as their profession. The most common clinical disciplines were physical therapy (38%), communication sciences and disorders (22%), and occupational therapy (10%). Across all 55 competency items, 95% of respondents expressed "a lot" or "some" interest in learning more, but only 19% reported "a lot" of knowledge. Respondents reported "a lot" of interest in a range of topics, including selecting outcome measures that are meaningful to patients (78%) and implementing research evidence in health systems (75%). "None" or "some" knowledge was reported most often in Systems Science areas such as understanding the interrelationships between financing, organization, delivery, and rehabilitation outcomes (93%) and assessing the extent to which research activities will improve the equity of health systems (93%). CONCLUSION: Results from this large survey of the rehabilitation research community indicate strong interest in LHS research competencies and opportunities to advance skills and training. IMPACT: Competencies where respondents indicated high interest and limited knowledge can inform development of LHS educational content that is most needed.

Beyond step counts: Including wear time in prosthesis use assessment for lower-limb amputation.

Introduction: The purpose of this study was to test a novel activity monitor that tracks the time a prosthesis is worn, and the nature of the ambulatory activity conducted with the prosthesis. These capabilities allow prosthesis users' wear and accommodation practices (e.g., temporary doffing) to be monitored, and the intensity of their activities to be assessed. Methods: A portable limb-socket motion sensing system was used to monitor doffs, walk bouts (≥5 steps), low locomotion (2-4 steps), stationary positions, and weight shifts in a group of transtibial prosthesis users. The relationship between doff time and active motion time was investigated, and durations of low and high intensity active motions were compared. Results: For the 14 participants tested, the median prosthesis day duration ranged from 12.8-18.8 h. Eleven participants typically doffed five or fewer times per day, and three participants typically doffed 10 or more times per day. Nine participants demonstrated a positive correlation between daily doff duration and active motion duration. Six participants spent more time in weight shifts than walk bouts, while eight participants spent more time in walk bouts than weight shifts. Conclusion: Capturing don time and temporary doffs and distinguishing weight shifts from walks may provide insight relevant to patient care. Longer-term monitoring studies should be conducted, and the clinical utility of the data evaluated.

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.

Prevalence of secondary prosthesis use in lower limb prosthesis users.

PURPOSE: Prostheses designed for daily use are often inappropriate for high-level activities and/or are susceptible to water damage and mechanical failure. Secondary prostheses, such as activity-specific or back-up prostheses, are typically required to facilitate uninterrupted participation in desired life pursuits. This study estimated the prevalence of secondary prosthesis use in a large, national sample of lower limb prosthesis users (LLPUs). METHODS: We conducted a secondary analysis of survey data from three cross-sectional studies that assessed mobility in LLPUs. Descriptive statistics were used to determine the percentage of secondary prosthesis users and percentages of LLPUs that used different type(s) of secondary prosthesis(es). Secondary prosthesis users and non-users were compared to identify differences in participant characteristics between groups. RESULTS: Of participants in the analysis (n = 1566), most (65.8%) did not use a secondary prosthesis. The most common secondary prosthesis types were back-up (19.2%) and activity-specific prostheses (13.5%). Secondary prosthesis users differed significantly from non-users with respect to gender, race, and other characteristics. CONCLUSIONS: Results suggest that secondary prosthesis use for most LLPUs is limited and may differ based on users' demographic and clinical characteristics. Future research should determine how LLPUs' health-related quality-of-life outcomes are affected by access to and use of secondary prostheses.Implications for RehabilitationSecondary prostheses, including activity-specific, back-up, and shower prostheses, have the potential to improve function, mobility, and participation for people who use lower limb prostheses.Most lower limb prosthesis users do not use secondary prostheses, and access to these devices may be related to users' demographic and clinical characteristics.Rehabilitation professionals play a key role in facilitating prosthesis users' access to secondary prostheses and should advocate for those who need them.

Modifying the five-time sit-to-stand test to allow use of the upper limbs: Assessing initial evidence of construct validity among lower limb prosthesis users.

The Five-time Sit-to-Stand (5xSTS) Test is a performance-based measure used by clinicians and researchers to assess the body functions needed to accomplish sit-to-stand transitions (e.g., lower limb strength, balance, and trunk control). The current requirements for performance of the 5xSTS Test (i.e., crossing arms over the chest) may not be appropriate for many, if not most lower limb prosthesis (LLP) users. The study aims were to (1) develop a modified five-time sit-to-stand (m5xSTS) Test protocol; (2) to examine initial evidence of known-groups construct validity among LLP users by comparing differences in performance by amputation level, amputation etiology, and functional level; and (3) to assess initial evidence of convergent construct validity by examining the correlations between m5xSTS performance with self-reported mobility (Prosthetic Limb Users Survey of Mobility (PLUS-M)), self-reported balance confidence (Activities-balance Confidence Scale (ABC)) and functional capability (comfortable walking speed). Three-hundred sixty-one LLP users participated in this cross-sectional study. The investigators developed a m5xSTS Test protocol that allows tested individuals to use different assistance strategies (i.e., use of upper limbs to push off thighs, push up from the armrests, or use a walker) when needed to perform the test. The investigators recorded m5xSTS Test times and assistance strategies. Significant differences in m5xSTS Test times were found between those who did and did not use an assistance strategy, as well as between participants grouped by different amputation level, etiology, and functional level. Significant moderate negative correlations were found between m5xSTS Test times and PLUS-M T-score (ρ = -0.42, p<0.001), ABC score (ρ = -0.42, p<0.001), and comfortable walking speed (ρ = -0.64, p<0.001), respectively. The m5xSTS Test allows LLP users to perform sit-to-stand transitions in a manner that accounts for their functional impairments, is consistent with post-amputation training, and is safe for the tested individual. Results from this study provide preliminary evidence of known groups and convergent construct validity for the m5xSTS Test with a large national sample of LLP users.

Rasch validation of the German translation of the Prosthetic Limb Users Survey of Mobility short forms in people with lower limb amputation.

BACKGROUND: Prostheses are a primary rehabilitative intervention for people after lower limb amputation. To appropriately measure the effectiveness of prosthetic interventions, valid and reliable measures of prosthetic mobility are required. The Prosthetic Limb Users Survey of Mobility (PLUS-M) is a promising instrument for measuring prosthesis users' mobility. However, German translations of the PLUS-M short forms have not yet been validated. OBJECTIVES: Rasch validation of the German translation of the PLUS-M short forms in people with lower limb amputation. STUDY DESIGN: This study is based on a cross-sectional survey of prosthesis-using lower limb amputees from a nation-wide cohort. METHODS: PLUS-M data (the 7-item and the 12-item shortforms; PLUS-M-7 and PLUS-M-12, respectively) from 194 lower limb prosthesis users were subjected to Rasch analysis, an advanced statistical method for assessing if the measurement properties of a questionnaire comply with a wide spectrum of psychometric requirements. RESULTS: Analysis showed appropriate rating scale functioning, good internal construct validity (item fit), unidimensionality, and good targeting of the PLUS-M-7 and PLUS-M-12 short forms. Moreover, the greater conditional measurement precision of PLUS-M-12 (regarding higher test information and lower standard error of mobility estimates) was quantified. CONCLUSIONS: Rasch analysis of the German translation of both PLUS-M short forms showed good psychometric qualities. In addition, our study showed that test scores from the PLUS-M-12 are more accurate. Therefore, the PLUS-M-12 is recommended for individual-level clinical applications (e.g., classification or change assessment).

The number of falls recalled in the past year and balance confidence predict the frequency of injurious falls by unilateral lower limb prosthesis users.

INTRODUCTION: Several personal characteristics have been associated with an increased risk of injurious falls by lower limb prosthesis (LLP) users. To date, however, none have been used to effectively predict the occurrence of injurious falls. OBJECTIVE: To develop a model that could predict the number of injurious falls over the next 6 months and identify fall-related circumstances that may increase the odds of a fall being injurious in unilateral LLP users. DESIGN: A secondary analysis of a prospective observational study. SETTING: Research laboratory. PARTICIPANTS: Sixty unilateral LLP users with a transtibial or transfemoral amputation. INTERVENTION: Not applicable. MAIN OUTCOME MEASURE(S): Participants' characteristics were recorded at baseline. Falls and their circumstances and consequences were collected prospectively over 6 months via monthly telephone calls. Multivariate negative binomial regression was used to predict the number of injurious falls over the next 6 months in LLP users. Incidence rate ratios (IRRs) were derived to determine the risk of an injurious fall. Bivariate logistic regression was used to identify the associations between injurious falls and fall-related circumstances. Odds ratios (ORs) were derived to characterize the odds that a fall would be injurious. RESULTS: The final multivariate model, which included the number of falls recalled in the past year (IRR = 1.31, 95% confidence interval [CI]: 1.01-1.71, p = .045) and balance confidence (p = .120), predicted the number of injurious falls in the next 6 months (χ2 (2) = 8.15, p = .017). Two fall-related circumstances were found to increase the odds that a fall would be injurious, fatigue due to activity (OR = 13.5, 95% CI: 3.50-52.3, p  = .001), and tiredness from a lack of sleep (OR = 5.36, 95% CI: 1.22-23.6, p = .026). CONCLUSION: The results suggest that the number of falls recalled in the past year and balance confidence scores predict the number of injurious falls an LLP user will experience in the next 6 months.

Development of a candidate item bank for measuring mobility of lower limb orthosis users.

BACKGROUND: Orthoses are often prescribed to improve mobility of people with chronic health conditions that affect lower limb function. Patient-reported survey instruments can be used to measure aspects of mobility that cannot be easily assessed in clinical or research settings. A population-specific item bank could be designed to measure aspects of mobility that are most important to lower limb orthosis users and used to evaluate the effects of orthoses. OBJECTIVE: To develop items for a new survey instrument to measure mobility of lower limb orthosis users. DESIGN: Survey items were developed using a qualitative item review process. SETTING: Focus groups were held by video conferencing. Cognitive interviews were conducted by telephone. PARTICIPANTS: Focus group and cognitive interview participants were adults with at least 6 months of experience using a lower limb orthosis that extended from the foot to a level above the ankle. METHODS: Research methods included focus groups with lower limb orthosis users, an item generation and reduction process that involved a stakeholder advisory panel, and cognitive interviews with target respondents. RESULTS: A total of 1180 extant items were identified in a literature review. Focus group participants (n = 29) provided feedback that informed the suitability of a construct definition and conceptual model. An advisory panel contributed to the selection of 118 candidate items for measuring orthotic mobility. Feedback from cognitive interview participants (n = 30) informed removal or revision of problematic items, resulting in a candidate bank of 100 mobility items. CONCLUSIONS: The rigorous qualitative methods applied here resulted in a large set of candidate items that spanned a range of situations relevant to moving with a lower limb orthosis. Next steps include administration of the candidate items to a large sample of lower limb orthosis users and calibration of the item bank.

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.

A novel portable sensor to monitor bodily positions and activities in transtibial prosthesis users.

BACKGROUND: Step activity monitors provide insight into the amount of physical activity prosthesis users conduct but not how they use their prosthesis. The purpose of this research was to help fill this void by developing and testing a technology to monitor bodily position and type of activity. METHODS: Thin inductive distance sensors were adhered to the insides of sockets of a small group of transtibial prosthesis users, two at proximal locations and two at distal locations. An in-lab structured protocol and a semi-structured out-of-lab protocol were video recorded, and then participants wore the sensing system for up to 7 days. A data processing algorithm was developed to identify sit, seated shift, stand, standing weight-shift, walk, partial doff, and non-use. Sensed distance data from the structured and semi-structured protocols were compared against the video data to characterize accuracy. Bodily positions and activities during take-home testing were tabulated to characterize participants' use of the prosthesis. FINDINGS: Sit and walk detection accuracies were above 95% for all four participants tested. Stand detection accuracy was above 90% for three participants and 62.5% for one participant. The reduced accuracy may have been due to limited stand data from that participant. Step count was not proportional to active use time (sum of stand, walk, and standing weight-shift times). INTERPRETATION: Step count may provide an incomplete picture of prosthesis use. Larger studies should be pursued to investigate how bodily position and type of activity may facilitate clinical decision-making and improve the lives of people with lower limb amputation.

A survey for characterizing details of fall events experienced by lower limb prosthesis users.

Despite their importance to fall prevention research, little is known about the details of real-world fall events experienced by lower limb prosthesis users. This gap can be attributed to the lack of a structured, population-specific fall survey to document these adverse health events. The objective of this project was to develop a survey capable of characterizing the circumstances and consequences of fall events in lower limb prosthesis users. Best practices in survey development, including focus groups and cognitive interviews with diverse samples of lower limb prosthesis users, were used to solicit input and feedback from target respondents, so survey content would be meaningful, clear, and applicable to lower limb prosthesis users. Focus group data were used to develop fall event definitions and construct a conceptual fall framework that guided the creation of potential survey questions and response options. Survey questions focused on the activity, surroundings, situation, mechanics, and consequences of fall events. Cognitive interviews revealed that with minor revisions, survey definitions, questions, and response options were clear, comprehensive, and applicable to the experiences of lower limb prosthesis users. Administration of the fall survey to a national sample of 235 lower limb prosthesis users in a cross-sectional preliminary validation study, found survey questions to function as intended. Revisions to the survey were made at each stage of development based on analysis of participant feedback and data. The structured, 37-question lower limb prosthesis user fall event survey developed in this study offers clinicians and researchers the means to document, monitor, and compare fall details that are meaningful and relevant to lower limb prosthesis users in a standardized and consistent manner. Data that can be collected with the developed survey are essential to establishing specific goals for fall prevention initiatives in lower limb prosthesis users.