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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.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.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.Practitioners may use individual responses to optimize socket vacuum pressure settings, balancing mechanical and physiological effects of EV for improved clinical outcomes.

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 evaluate the effects of orthoses.The aim of this research was to develop items for a new survey instrument to measure mobility of lower limb orthosis users.A qualitative item review process 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.Focus groups were held by video conferencing. Cognitive interviews were conducted by telephone.Focus group and cognitive interview participants were adults with at least six months of experience using a lower limb orthosis that extended from the foot to a level above the ankle.A total of 1,326 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.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. This article is protected by copyright. All rights reserved.

Objective To evaluate test-retest reliability and related measurement properties of items developed to assess best, worst, and average prosthetic socket comfort. Design Methodological research to assess test-retest reliability of four individual socket comfort survey items. Socket comfort items were included in a self-report paper survey, which was administered to participants 2-3 days apart. Setting General community. Participants A minimum convenience sample of 63 participants was targeted for this study; 72 lower limb prosthesis users (>1-year post-amputation) completed the survey and were included in the final dataset. Interventions Not applicable. Main Outcome Measure The Expanded Socket Comfort Score (ESCS) was adapted from the original Socket Comfort Score (SCS). The original SCS is a single-item self-report instrument developed to assess a lower limb prosthesis user's current socket comfort. Three additional items were designed to assess the user's best, worst, and average socket comfort over the previous seven days. Results Best, worst, and average socket comfort items demonstrated better reliability, as indicated by higher intra-class correlation coefficients. As such, these items also exhibited lower measurement error and smaller minimal detectable change values than the item that measured current socket comfort. However, test-retest coefficients for all four items were below the level desired for evaluation of within-individual changes of socket comfort. Conclusions Items that assess best, worst, and average comfort provide a more stable measurement of socket fit than the existing SCS instrument. While administration of all four items may provide more comprehensive assessment of a lower limb prosthesis user's socket fit, administrators should expect variations in scores over time due to the variable nature of the underlying construct over time. Future research should examine whether a multi-item socket comfort scale provides an improved overall assessment of socket fit.

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.

Mechanical testing is the principal method used to quantify properties of commercial prosthetic feet in a controlled and standardized manner. To test feet in a mechanical testing machine without overconstraining the system, tangential shear forces must be minimized. However, there is scant published information comparing techniques for reducing shear forces during mechanical testing. Furthermore, there are no data on variability in linear stiffness across testing sessions.To compare techniques for reducing shear forces during mechanical testing of prosthetic feet and to evaluate variation in linear stiffness across testing sessions.Repeated measures.Force-displacement data were collected at two pylon progression angles, one for the forefoot and one for the heel, and compared across three conditions: roller plate (RoPl), low-friction interface on the shoe (SB), and no method for reducing shear forces (NoSB). Data were collected for a range of commercial prosthetic foot models and sizes. Select data were collected over multiple days to assess variation over test sessions.Differences in stiffness between RoPl and SB test conditions ranged from -0.9% to +2.6% across foot models. By contrast, differences between RoPl and no method for reducing shear conditions ranged from -2.9% to +14.6%. Differences in linear stiffness between test sessions ranged from -2.2% to +3.6%.Methods for reducing shear force in this study demonstrated roughly equivalent effects. Thus, a low-friction interface may be used as a less expensive and less complex method for reducing shear force in prosthetic foot testing. In addition, mechanical testing results were relatively consistent across multiple test sessions, lending confidence to test consistency.

Management of socket fit is challenging for people using lower-limb prostheses because of residual limb volume fluctuation throughout the day. Releasing socket pressures during sitting (partial doffing) may help users increase their limb volume after they have undergone volume loss earlier in the day. The purpose of this research was to develop and evaluate a system to allow for quick and easy locking pin and socket panel release during sitting and relock upon standing. The system was to allow the partial doff tether length to be custom set for each user, accomplish release and relock in less than 2.0 s each, require only one hand, and require a finger push force comparable to a push button on a phone. A motor-driven release/relock system (240 g build weight) housed within the socket adjusts locking pin tether length, and an instrumented ratcheting dial adjusts socket panel position. Three participants with a trans-tibial amputation operated the system properly using one hand. For a partial doff, users preferred a tether length between 5 and 6 cm. All users executed release within 1.5 s and relock within 1.5 s.

The Prosthetic Limb Users Survey of Mobility (PLUS-M) is a self-report item bank designed to measure the abilities with which people with lower limb amputation perform physical activities. Although PLUS-M includes items that span a range of mobility, additional items are needed to accurately measure mobility of highly active prosthesis users, such as athletes and service members with lower limb amputation. The aim of this study was to understand mobility in highly active lower limb prosthesis users to inform the development of new items for the PLUS-M item bank.Focus groups were conducted with active, lower limb prosthesis users from across the USA. In-person and online focus groups were conducted by a trained facilitator using a semi-structured guide. Focus group transcripts were reviewed and coded by two researchers. Thematic analysis was used to identify important experiences across participants.Twenty-nine participants took part in four focus groups. Three resultant themes were identified: mobility after amputation, mobility characteristics, and healthcare providers and systems.Identified themes inform clinician and researcher understanding of mobility in highly active lower limb prosthesis users. The results of this study will be used to inform development of high-activity items for the PLUS-M item bank.Implications for rehabilitationParticipants described engagement in high-level activities as a learning process that included elements such as equipment challenges and modifications, pain and injury, and the need to trust the prosthetic limb.Participants with lower limb amputation who use prostheses identified mobility characteristics, such as postural changes, terrain, and obstacles, that influenced their ability to perform high-level activities.High-level mobility characteristics identified in these focus groups can be integrated into a revised version of the Prosthetic Limb Users Survey of Mobility to assess mobility in active adults and athletes with amputation.Rehabilitation professionals play an important role in facilitating access to specialized prosthetic components and training that can help patients achieve their mobility goals and potential.

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Previous studies investigating limb volume change with elevated vacuum have shown inconsistent results and have been limited by out-of-socket volume measurements and short, single-activity protocols.To evaluate the effectiveness of elevated vacuum for managing limb fluid volume compared to suction suspension with an in-socket measurement modality during many hours of activity.Fixed-order crossover design with a standardized out-of-laboratory activity protocol.Transtibial electronic elevated vacuum users participated in two sessions. Elevated vacuum was used during the first session, and suction suspension in the second. Participants completed a 5.5-h protocol consisting of multiple intervals of activity. In-socket residual limb fluid volume was continuously measured using a custom portable bioimpedance analyzer.A total of 12 individuals participated. Overall rate of fluid volume change was not significantly different, though the rate of posterior fluid volume change during Cycle 3 was significantly lower with elevated vacuum. Although individual results varied, 11 participants experienced lower overall rates of fluid volume loss in at least one limb region using elevated vacuum.Elevated vacuum may be more effective as a volume management strategy after accumulation of activity. Individual variation suggests the potential to optimize the limb fluid volume benefits of elevated vacuum by reducing socket vacuum pressure for some users.A better understanding of how elevated vacuum (EV) affects residual limb fluid volume will allow prosthetists to make more informed clinical decisions regarding accommodation strategies designed to improve daily socket fit.

Objective A major barrier to reducing falls among users of lower limb prostheses (LLP) has been an absence of statistical indices required for clinicians to select and interpret scores from performance-based clinical tests. The study aimed to derive estimates of reliability, measurement error, and minimal detectable change values in performance-based clinical tests administered to unilateral LLP users. Methods A total of 60 unilateral LLP users were administered the Narrowing Beam Walking Test, Timed ``Up and Go'' (TUG), Four Square Step Test (FSST), and 10-Meter Walk Test on 2 occasions, 3 to 9 days apart. Intraclass correlation coefficients (ICCs) were calculated to assess interrater and test-retest reliability, while standard error of measurement (SEM) and minimal detectable change (MDC90) were derived to establish estimates of measurement error in individual scores or changes in score for each test. Results Interrater reliability ICCs (1,1) were high for all tests (ie, ≥0.98). Test-retest ICCs (2,1) varied by test, ranging from .88 for the TUG to .97 for the FSST. SEM and MDC90 varied between .39 and .96 and between .91 seconds and 2.2 seconds for the time-based tests (FSST, TUG, 10-Meter Walk Test). SEM and MDC90 for the Narrowing Beam Walking Test were .07 and .16, respectively. Conclusion With the exception of the TUG, studied tests had test-retest ICCs (2,1) that exceeded the minimum required threshold to be considered suitable for group- and individual-level applications (ie, ICC ≥ 0.70 and ≥ 0.90, respectively). Future research on individuals with dysvascular and transfemoral amputations or in specific age categories is required. Impact Along with published validity indices, these reliability, error, and change indices can help clinicians select balance tests suitable for LLP users. They can also help clinicians interpret test scores to make informed, evidence-based clinical decisions.

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, ppp

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.

Objective To determine if the two-minute walk test (2MWT) could serve as an alternative measure of high-level mobility in lower limb prosthesis users when circumstances preclude administration of the Comprehensive High-level Activity Mobility Predictor (CHAMP). Design Cross-sectional study. Setting Indoor recreational athletic field and gymnasium Subjects Fifty-eight adult lower limb prosthesis users with unilateral or bilateral lower limb amputation who participate in recreational athletic activities. Intervention N/A Main Measures The 2MWT and CHAMP while using their preferred prosthesis(es) on an indoor artificial athletic field or hardwood gymnasium floor. Results Thirty-nine men and nineteen women with a median age of 38.3 years participated in the study. Most participants experienced amputation(s) due to trauma (62%) or tumor (10%) and were generally higher functioning (K4 (91.4%) and K3 (8.6%)). The median (range) score for the CHAMP was 23.0 points (1.5–33.5) and the mean ± standard deviation (range) 2MWT distance walked was 188.6 ± 33.9 m (100.2–254.3 m). The CHAMP demonstrated a strong positive relationship with 2MWT (r = 0.83, p Conclusions Although the 2MWT does not test multi-directional agility like the CHAMP, they were found to be highly correlated. If space is limited, the two-minute walk test can serve as an alternative measure for assessing high-level mobility capabilities in lower limb prosthesis users.

To assess the clinical resources available for the assessment of health outcomes in people with lower limb amputation and to understand barriers and facilitators associated with use of standardized outcome measures in clinical practice.Cross-sectional survey.General community (online).A volunteer sample of prosthetic practitioners was recruited through national professional organizations. Eligible participants were practitioners certified by a professional prosthetics organization and currently practicing as a prosthetist, prosthetist-orthotist, or prosthetic assistant.Not applicable.A custom-designed online survey on clinical use of patient-reported and performance-based standardized outcome measures to assess patients with lower limb amputation.A total of 375 participants completed the survey. Most participants (79%) reported that they are encouraged or required to administer standardized outcome measures in their clinic or facility. Most participants reported that use of patient-reported and performance-based outcome measures are within their scope of practice (88%) and that they have the knowledge required for outcomes measurement (84%). Few participants agreed that outcomes measurement is standardized across the profession (30%). Most participants had access to small spaces and equipment for outcomes measurement, such as short hallways (65%-94%), stairs (69%), and tablets with wireless internet connection (83%). Most participants reported that they would be willing to spend between 5 (36% of participants) and 10 (43% of participants) minutes on self-reported surveys, and between 10 (41% of participants) and 20 (28% of participants) minutes on performance-based tests.Outcomes measurement is encouraged or expected in contemporary prosthetic practice. Strategies to improve standardization and efficiency of administration are needed to facilitate routine use of outcome measures in clinical care.

PURPOSE People with lower limb impairments are often prescribed orthoses to preserve or enhance their mobility. Exploration of mobility experiences common among orthosis users may provide insights into how orthoses, and other mobility aids, are utilized and regarded. The objective of this study was to broadly explore how lower limb orthosis users describe their mobility. MATERIALS AND METHODS Four focus groups were held online with participants who lived in the U.S. or Canada. Participants had at least six months of experience using an ankle-foot- and/or a knee-ankle-foot-orthosis for one or both legs. All discussions were transcribed and coded. Thematic analysis was used to identify cross-cutting themes. RESULTS Participants included 29 orthosis users with a variety of health conditions. Inter-related themes, including personal factors, situational contexts, and assistance were identified as elements that influenced participants' mobility. Participants described a process of modifying their mobility through the use and non-use of one or more mobility aids. CONCLUSIONS The current study findings may assist clinicians in developing strategies to optimize orthosis users' mobility in different situations. Experiences described by participants in this study may also help researchers identify aspects of mobility most pertinent to orthosis users and inform the development of new outcome measures.Implications for RehabilitationPeople who use lower-limb orthoses share common mobility experiences, despite differences in health diagnoses.Orthosis users often have opportunities to modify their mobility by choosing to use or not use their brace(s) and/or handheld mobility aids.When providing mobility aid interventions, clinicians should consider how each patient's individual characteristics, including physical characteristics (e.g., the health condition and how it presents, pain, fatigue) and psychosocial characteristics (e.g., fear and confidence, self-motivation, emotional responses), can affect mobility.Clinicians may be able to help patients optimize their mobility by asking about environmental obstacles they regularly encounter and recommending strategies for utilization of mobility aids, including simultaneous use of multiple aids, use of one aid, or choosing not to use any aids, depending on the activity and situation.Clinicians should inquire about all mobility aids available to a patient at home and in the community, including fixed objects, and consider how new mobility aid interventions might affect the patient's mobility when used alone and in combination with other forms of assistance.

The purpose of this research was to pursue an innovative cyclic panel-pull strategy during ambulation to minimize limb fluid volume loss in transtibial prosthesis users. Participants' traditional socket shapes were duplicated, and test sockets prepared with three adjustable motor-driven panels that were controlled by a microprocessor. After donning the prosthesis, participants' liners were fastened to the panels. During a 40 min test session, participants conducted three cycles of sitting (5 min) and walking (8 min). During the 5th and 6th min of each cycle of walking, the panels were cyclically pulled outward in late stance phase, decreasing pressure on the residual limb. Panels were returned to their original position in swing phase. Eight of twelve participants gained more fluid volume while walking when panel-pull was added than when it was removed. When the liner was uncoupled from the panels and panel-pull was executed, eight of twelve participants gained less fluid volume compared to when the liner was fastened to the panels. Panel-pull may facilitate limb fluid volume retention in transtibial prosthesis users. Efforts to simplify the design so that it can be implemented in long-term testing during at-home use should be considered.

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.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.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).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.

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Practice effects have been observed among performance-based clinical tests administered to prosthesis-users. Their impact on test applications remains unknown.To determine whether scoring a clinical balance test using conventional procedures that do not accommodate practice effects reduces its diagnostic accuracy relative to scoring it using recommended procedures that do accommodate practice effects.Cross-sectional study.Narrowing Beam Walking Test data from 40 prosthesis users was scored using recommended methods (i.e. average of trials 3-5) and conventional methods applied to other tests (i.e. mean or best of trials 1-3). Area under the receiver operating characteristic curve for each method was compared to 0.50, to determine if it was better than chance at identifying prosthesis-users with a history of falls, and to 0.80, to determine if it surpassed a threshold recommended for diagnostic accuracy.Receiver operating characteristic curve area decreased when the Narrowing Beam Walking Test was scored using conventional rather than recommended procedures. Furthermore, when scored using conventional procedures, the NBWT no longer discriminated between prosthesis-users with and without a history of falls with a probability greater than chance, or exceeded recommended diagnostic thresholds.Scoring the Narrowing Beam Walking Test using conventional procedures that do not accommodate practice effects decreased its diagnostic accuracy among prosthesis-users relative to recommended procedures. Conventional scoring procedures may limit the effectiveness of performance-based tests used to screen for fall risk in prosthesis-users because they do not mitigate practice effects. The influence of practice effects on other tests, and test applications (e.g. clinical evaluation and prediction), is warranted.Scoring a clinical balance test using conventional procedures that do not mitigate practice effects reduced its diagnostic accuracy. Changing administration and scoring procedures to accommodate practice effects should be considered to improve the diagnostic accuracy of other performance-based balance tests.

BACKGROUND: Loss of residual limb volume degrades socket fit and may require accommodation. OBJECTIVES: To examine if either of two accommodation strategies executed during resting, socket release with full socket size return and socket release with partial socket size return, enhanced limb fluid volume retention during subsequent activity. STUDY DESIGN: Two repeated-measures experiments were conducted to assess the effects of socket release on limb fluid volume retention. METHODS: Limb fluid volume was monitored while participants wore a socket with a single adjustable panel. Participants performed eight activity cycles that each included 10 minutes of sitting and 2 minutes of walking. The socket’s posterior panel and pin lock were released during the 5(th) cycle while participants were sitting. In one experiment (Full Return), the socket was returned to its pre-release size; in a second experiment (Partial Return), it was returned to 102% of its pre-release size. Short-term and long-term limb fluid volume retention were calculated and compared to a projected, No Intervention condition. RESULTS: Partial Return and Full Return short-term retentions and Partial Return long-term retention were greater than those projected under the control condition (p

Introduction Prosthetists have limited knowledge of their patients' use of a prosthesis outside of the clinical environment. Prosthesis-mounted monitors can be used to directly measure patients' prosthesis use and activity. Prosthetists' opinions regarding potential clinical applications for sensor-based information may inform further development of this technology. A pilot study was conducted to assess prosthetists' perceptions of prosthesis use and activity information obtained by a monitoring system. Materials and methods Three local prosthetists were recruited to participate in the study. One patient with transtibial amputation from each prosthetist volunteered to wear limb presence and activity monitors for two weeks. Collected data were used to determine prosthesis use and activity. Each prosthetist completed a survey, examined clinical reports of their patient's prosthesis use and activity, and participated in a semi-structured interview. Survey results and interview transcripts were analyzed to identify and compare prosthetists' perceptions. Results Prosthesis use and activity varied among patients. Prosthetists over- and under-estimated patient activity, relative to measurements recorded by the monitors. All three prosthetists selected multiple clinical applications for the prosthesis use and activity information in the survey, and several additional applications were suggested during the interviews. When presented with multiple report formats, prosthetists found features of each to be clinically useful. Conclusions Prosthesis-mounted monitors may provide prosthetists with a better understanding of their patients' prosthesis use and activity. Information provided by the monitoring system may inform clinical decisions and promote evidence-based practices.

Background Small intermittent adjustments of socket size using adjustable sockets may be a means for people with transtibial amputation to better maintain residual limb fluid volume and limb position while using a prosthesis. Methods Socket size, limb fluid volume, and distance from the limb to the socket, termed “sensed distance,” were recorded while participants with transtibial amputation walked on a treadmill wearing a motor-driven, cabled-panel, adjustable socket. Researchers made frequent socket size adjustments using a mobile phone app to identify participants' acceptable socket size range. Limb fluid volume and sensed distance were then monitored as incremental adjustments were made to the socket. Findings Prosthesis users in this study (n = 10) accepted socket sizes between −5% and +5% of their neutral socket volume. There was a rapid increase in limb fluid volume and sensed distance upon socket enlargement, and a rapid decrease upon reduction. Subsequently, there were gradual changes in fluid volume and sensed distance. While visually monitoring limb fluid volume data in real time, researchers were able to adjust socket size to maintain consistent limb fluid volume within a −0.7% to +0.9% volume change for 24 min. Interpretation Participant residual limbs compensated to socket size adjustment. Using socket-mounted sensors to monitor limb-socket mechanics, an automatic adjustable socket that maintains limb fluid volume may be possible and may improve socket fit in instances where fit deteriorates during use.

Background More than 50% of lower limb prosthesis (LLP) users report falling at least once a year, placing them at high risk for adverse health outcomes such as decreased mobility and diminished quality of life. Efforts to decrease falls in LLP users have traditionally focused on developing clinical tests to assess fall risk, designing prosthetic components to improve patient safety, and identifying risk factors to recognize potential fallers. Little attention has been directed toward recording, reporting, and characterizing the circumstances of falls in LLP users. Identifying the most common types of falls could help guide and prioritize clinical and research needs. Objective To characterize the frequency and circumstances of falls reported by unilateral LLP users. Design Secondary analysis of data from 2 cross-sectional studies. Setting Outpatient clinic and research laboratory. Participants Ambulatory unilateral transtibial and transfemoral LLP users (N = 66). Intervention None. Outcome A fall-type classification framework was developed based on biomechanical theory and published falls terminology. Self-reported falls and accompanying narrative descriptions of LLP users’ falls in the previous 12 months were analyzed with the framework. Frequencies, estimated proportions, and estimated counts were compared across fall circumstances using 95% confidence intervals. Results Thirty-eight participants (57.6%) reported 90 falls during the previous year. All reported falls were successfully categorized using the proposed framework. Most falls occurred from disruptions to the base of support, intrinsic destabilizing factors, and a diverse set of fall patterns. Walking on level terrain was the most common activity at the time of a fall. Conclusion This secondary analysis showed that falls remain frequent in ambulatory LLP users and that clinicians and researchers might wish to prioritize falls owing to disruptions of the base of support that occur while walking. Additional research with a larger sample is required to confirm and expand these results. Level of Evidence III

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.

Despite the effects of prosthetic foot mechanical properties on gait of people with lower limb amputation, scant forefoot and heel stiffness data exist to help guide prosthetic foot prescription.To measure forefoot and heel linear stiffness properties across commonly prescribed commercial prosthetic foot models and to describe variations in stiffness across feet targeted for users with different body weights and foot sizes.Mechanical testing of five types of commercial prosthetic feet across nine user body weight and foot size combinations.Linear forefoot and heel stiffness (force vs. displacement) data were collected for 41 prosthetic feet. Quasistatic testing was conducted at -15 and +20 degrees to isolate loading of the heel and forefoot, respectively.Overall, there was a significant relationship between user body weight and both forefoot and heel stiffness, when adjusted for foot size and type ( P0.001). However, there were a substantial number of inconsistencies across foot type within example user body weight and foot sizes combination. Furthermore, the relative order of forefoot stiffness across foot type differed from the relative order of heel stiffness across foot type.The inconsistencies and differences in relative order of forefoot and heel stiffness across commercial foot type suggest the importance of publishing objective stiffness and other mechanical properties of prosthetic feet. These data can aid clinicians in better matching mechanical properties of prosthetic feet with the functional goals and abilities of prosthesis users.

To explore lived experiences, and identify common themes as well as vocabulary associated with fall-related events in lower limb prosthesis (LLP) users.Five focus groups of LLP users from across the United States were conducted remotelyFocus group participants (n = 25) described experiences associated with fall-related events that resulted in the identification of six themes: (1) memories of fall-related events are shaped by time and context, (2) location and ground conditions influence whether falls occur, (3) some activities come with more risk, (4) fall-related situations are multi-faceted, and often involve the prosthesis, (5) how LLP users land, but not the way they go down, tends to vary, and (6) not all falls affect LLP users, but some near-falls do.Consideration for where LLP users fall, what they are doing when they fall, how they fall, what occurs as a result of a fall, and how well memory of a fall persists may enhance recording and reporting of falls, contribute to development of improved fall risk assessment tools, and inspire the design and function of prosthetic componentry for patient safety.Implications for rehabilitationFalls are a common problem in lower limb prosthesis (LLP) users that can lead to adverse health outcomes.Concerns over near falls, not just falls, may merit greater attention from rehabilitation professionals.Elements of the lived experience that appear unique to LLP users include the role of prosthetic fit, function, and comfort in losing and/or recovering balance; as well as the tendency of LLP users to modify rather than stop or avoid activities associated with falls.

Objective Falls are a frequent and costly concern for lower limb prosthesis (LLP) users. At present, there are no models that clinicians can use to predict the incidence of future falls in LLP users. Assessing who is at risk for falls, therefore, remains a challenge. The purpose of this study was to test whether easily accessible clinical attributes and measurements predict the incidence of future falls in LLP users. Methods In this prospective observational study, a secondary analysis of data from 60 LLP users was conducted. LLP users reported the number of falls that they recalled over the past year before prospectively reporting falls over a 6-month observation period via monthly telephone calls. Additional candidate predictor variables were recorded at baseline. Negative binomial regression was used to develop a model intended to predict the incidence of future falls. Results The final model, which included the number of recalled falls (incidence rate ratio = 1.13; 95% CI = 1.01 to 1.28) and Prosthetic Limb Users Survey of Mobility T-scores (incidence rate ratio = 0.949; 95% CI = 0.90 to 1.01), was significantly better than a null model at predicting the number of falls over the next 6 months (χ22 = 9.76) and fit the observed prospective fall count data (χ256 = 54.78). Conclusion The number of recalled falls and Prosthetic Limb Users Survey of Mobility T-scores predicted the incidence of falls over the next 6 months in established, unilateral LLP users. The success and simplicity of the final model suggests that it may serve as a screening tool for clinicians to use for assessing risk of falls. Additional research to validate the proposed model in an independent sample of LLP users is needed. Impact Owing to its simplicity, the final model may serve as a suitable screening measure for clinicians to ascertain an initial evaluation of fall risk in established unilateral LLP users. Analyzing falls data as counts rather than as a categorical variable may be an important methodological consideration for falls prevention research.

Prosthetic foot stiffness plays a key role in the functional mobility of lower limb prosthesis users. However, limited objective data exists to guide selection of the optimal prosthetic foot stiffness category for a given individual. Clinicians often must rely solely on manufacturer recommendations, which are typically based on the intended user’s weight and general activity level. Availability of comparable forefoot and heel stiffness data would allow for a better understanding of differences between different commercial prosthetic feet, and also between feet of different stiffness categories and foot sizes. Therefore, this study compared forefoot and heel linear stiffness properties across manufacturer-designated stiffness categories and foot sizes. Mechanical testing was completed for five types of commercial prosthetic feet across a range of stiffness categories and three foot-sizes. Data were collected for 56 prosthetic feet, in total. Testing at two discrete angles was conducted to isolate loading of the heel and forefoot components, respectively. Each prosthetic foot was loaded for six cycles while force and displacement data were collected. Forefoot and heel measured stiffness were both significantly associated with stiffness category (p = .001). There was no evidence that the relationships between stiffness category and measured stiffness differed by foot size (stiffness category by size interaction p = .80). However, there were inconsistencies between the expected and measured stiffness changes across stiffness categories (i.e., magnitude of stiffness changes varied substantially between consecutive stiffness categories of the same feet). While statistical results support that, on average, measured stiffness is positively correlated with stiffness category, force-displacement data suggest substantial variation in measured stiffness across consecutive categories. Published objective mechanical property data for commercial prosthetic feet would likely therefore be helpful to clinicians during prescription.

Background Energy expenditure (EE) is often greater in people with lower-limb amputation, compared with healthy controls, because of the biomechanical compensations needed to walk with a prosthesis. Compensatory movements are required to stand with a prosthesis; however, little is known about whether standing with a prosthesis also requires greater EE. Objective The goal of this study was to examine the effect of standing and sitting positions on EE in people with transtibial amputation and matched controls. Study design This is a secondary analysis. Methods Energy expenditure data from people with unilateral, transtibial amputation because of nondysvascular causes were compared with data from age- and sex-matched controls without amputation. Energy expenditure was defined as the mean volumetric rate of oxygen consumed over the last 2 of 5 minutes in each position and measured with a portable breath-by-breath metabolic analyzer. Repeated-measures analysis of variance was used to examine the effects of position (sitting and standing) and group (amputation and control) on EE. Results A significant interaction effect indicated participants with amputation showed a significantly greater increase in standing EE relative to sitting EE (26.2%) than did controls (13.4%). Simple main effects showed EE in standing was significantly greater than EE in sitting for both groups, but there were no significant differences in EE between groups during sitting or standing. Conclusions Energy expenditure in standing, when measured relative to EE in sitting, is significantly greater in people with amputation. This result indicates that additional energy may be required to maintain an upright position with a lower-limb prosthesis.

Background Performance-based tests are viewed as a gold standard for measuring physical capability. Practice effects, however, may threaten their predictive, discriminative, and evaluative applications. Despite these potential consequences, practice effects have received limited attention in users of lower limb prostheses (LLP). Objective To perform an initial characterization of the occurrence, time-course, and magnitude of practice effects in three performance-based tests administered to users of LLP. Design Secondary analysis of data from a multisite repeated-measures study. Setting Outpatient clinic and research laboratory. Participants Convenience sample of established ambulatory users of unilateral transtibial and transfemoral prostheses (n = 60). Intervention Not applicable. Main outcome measures Practice effects were identified as significant changes in slope of participants' cumulative trial-by-trial records. The occurrence, time-course, and magnitude of practice effects were computed for the Timed Up and Go (TUG), Four Square Step Test (FSST), and the 10-m Walk Test (10mWT). Results Across tests, practice effects were observed in 45% to 76% of participants. The proportion of participants with practice effects (ie, occurrence) was significantly greater for the FSST than the 10mWT (P = .008). The median number of trials (ie, time-course) required for participants to reach a consistent level of performance was not significantly different between tests (FSST: 4 trials, TUG: 4 trials; 10mWT: 3.5 trials; P = .481). Practice effect magnitude (ie, difference between the mean of trials during the plateau and best performance over the first two trials) was significantly greater than zero for the FSST (1.6 s; 16%) and TUG (1.4 s; 13%) (P Conclusion Results indicate that the FSST, TUG, and 10mWT were susceptible to practice effects in this sample of users of LLP. Practice effects may obscure significant differences in walking and balance ability, and thereby, in the absence of modifications, limit the use of these tests for making individual patient clinical decisions and analyzing group-level data.

Elevated vacuum (EV) is suggested to improve suspension and limb volume management for lower limb prosthesis users. However, few guidelines have been established to facilitate configuration of EV sockets to ensure their safe and proper function. A benchtop model of an EV socket was created to study how prosthetic liner tensile elasticity, socket fit, and socket vacuum pressure affect liner displacement and subsequent pressure on the residual limb. A domed carbon fiber layup was used to represent an EV socket. Inserts were used to simulate various air gaps between the socket and liner. Various prosthetic liner samples were placed under the carbon fiber layup. Liner displacement and the corresponding pressure change underneath the liner were measured as vacuum was applied between the liner sample and socket wall. Tissue vacuum pressure increased linearly with socket vacuum pressure until the liner contacted the socket wall. Predicted tissue vacuum pressure matched well with experimental results. Findings suggest that the effect of vacuum pressure on the residual limb is primarily determined by air gap distance. The developed model may be used to assess effects of EV on residual limb tissues based on an individual's socket fit, liner characteristics, and applied vacuum. Understanding the physiological effects of EV on the residual limb could help practitioners avoid blister formation and improve EV implementation.

IntroductionA challenge in the engineering of auto-adjusting prosthetic sockets is to maintain stable operation of the control system while users change their bodily position and activity. The purpose of this study was to test the stability of a socket that automatically adjusted socket size to maintain fit. Socket release during sitting was conducted between bouts of walking.MethodsAdjustable sockets with sensors that monitored distance between the liner and socket were fabricated. Motor-driven panels and a microprocessor-based control system adjusted socket size during walking to maintain a target sensed distance. Limb fluid volume was recorded continuously. During eight sit/walk cycles, the socket panels were released upon sitting and then returned to position for walking, either the size at the end of the prior bout or a size 1.0% larger in volume.ResultsIn six transtibial prosthesis users, the control system maintained stable operation and did not saturate (move to and remain at the end of the actuator’s range) during 98% of the walking bouts. Limb fluid volume changes generally matched the panel position changes executed by the control system.ConclusionsStable operation of the control system suggests that the auto-adjusting socket is ready for testing in users’ at-home settings.

People with lower limb amputation report the need to concentrate on walking. Dual-task paradigms are often used to study such interactions between cognition and the control of balance and gait in people with lower limb amputation.To summarize evidence related to dual-task standing and walking in people with lower limb amputation and discuss implications for future research.Structured review.A structured search was completed in PubMed, CINAHL, and Web of Science from database inception to May 2017. Eligible articles were in English, included participants with lower limb amputation, and assessed dual-task standing or walking. Study information was extracted by one reviewer and assessed for accuracy by a second.A total of 12 articles met eligibility criteria. Seven examined differences in dual-task standing or walking, and five assessed dual-task walking across microprocessor-controlled and non-microprocessor-controlled prosthetic knee conditions.Results suggest that (1) dual-task interference in standing is greater for people with lower limb amputation than non-amputees and (2) the use of microprocessor-controlled knees improves dual-task performance for people with limited mobility compared to non-microprocessor-controlled knees. The small number of studies, diversity of dual-task methods, and methodological limitations challenge the synthesis of study results. Future research should assess specific clinical characteristics that can affect dual-task performance in people with lower limb amputation.Understanding how people with lower limb amputation use increased attention in balance and gait to compensate for limb loss can inform prosthetic interventions and training. Dual-task research suggests that people with amputation use increased cognitive control for standing compared to controls and microprocessor-controlled knees improve dual-task walking in people with limited mobility.

Use of elastomeric or “gel” liners in prosthetics practice has become increasingly common, with recent data suggesting that practitioners select gel liners for about 85% of their prosthetic patients.1 To accommodate the clinical needs of a broad range of prosthetic limb users, liner manufacturers have created an array of different liner products. Although elastomeric liners are derived primarily from the same base materials (i.e., urethane, silicone, and thermoplastic elastomer (TPE]), differences in a liner’s chemical composition, shape, geometry, and manufacturing determine a liner’s overall performance. Presence of fabric backing, antibacterial additives, or features such as sealing sleeves, distal pads, or reinforcement can additionally affect mechanical performance of a liner. Given the number of variables that contribute to a liner’s design, it is not surprising that a large number of liner products are commercially available – a recent study identified more than 70 liner products on the market.2 Despite the availability of so many different liner products, a recent survey indicated that a typical practitioner choses among only two or three products when selecting liners for his or her prosthetic patients.2 An explanation for such limited selection among many available options may be a lack of comparable, objective information about the similarities and differences among liner products.3 Without information about how a new liner compares to the two or three familiar products, practitioners are hesitant to change. The same study found that only 33% of practitioners surveyed obtained information from scientific journals, while the majority sought information directly from manufacturers (94%) or clinical magazines (65%). These results suggest there is a need to distinguish liners and provide practitioners with practical information to help them identify products that best match individual patient needs. The purpose of this research study was to characterize mechanical properties of commonly used prosthetic liner products and to compare findings with previous liners characterized in the literature. We also evaluated the influence of design variables fabric backing and liner thickness on testing results. Selecting a liner for an individual patient may require the practitioner optimize the most preferred property or identify a liner that exhibits a balance among several preferred properties.

Residual limb volume loss over the day is a source of socket fit problems for people using transtibial prostheses.1. Research studies have shown that prosthesis users may gain fluid volume during walking, but lose fluid volume during sitting.2 Pin suspension systems may accentuate limb fluid volume loss during sitting. With the distal end of the residual limb held in place by the pin, the posterior proximal residual limb tissues in the popliteal area are stretched tightly over the posterior brim of the socket, focusing stress that may reduce limb fluid volume and cause soft-tissue damage. If the foot is flat on the floor, anterior distal pressures may increase. Intermittent doffing may reduce fluid volume loss and mitigate socket fit problems.3 In a study on 16 people with transtibial amputation, a 30-minute doff performed after activity significantly increased limb fluid volume compared with not doffing. While doffing a prosthesis with locking-pin suspension during sitting either partially or completely may reduce socket fit problems caused by fluid volume loss, re-donning the prosthesis can often be difficult. Typically, donning requires the user has access to the socket (i.e., the user must remove pants or other lower-limb garments). Further, the user may have difficulty aligning the locking pin with the shuttle lock since it is not visible during donning. A mechanism that conveniently allows partial doffing and facilitates easy re-donning may help prosthesis users to implement intermittent doffing practices and overcome discomfort and fluid volume loss during sitting. Several systems have been designed to facilitate re-donning, with most of them using a fabric pull cord that passes through a hole in the distal end of the socket.4 The user draws the cord to pull in and seat the liner. One system (Lanyard Plunger Pin, Bulldog Tools Incorporated, Lewisburg, Ohio) is simply a cord affixed to a locking pin. Other systems eliminate the locking pin and shuttle lock and instead attach the cord to the liner using a threaded fastener5 (Icelock 300, Ossur, Reykjavik, Iceland; Keep It Simple Suspension,6 KISS Technologies, Baltimore, Maryland; Hook and Loop System,7 HOLO). The cord is pulled proximally by the user and held against the socket to maintain tension in the cord. One system uses a ratcheting mechanism that allows tension to be incrementally applied to the cord.5 The primary limitations of all of these systems are that users must have direct access to the socket to operate them, and users must have sufficient dexterity, balance, and strength to pull the cord taut. Further, systems without locking mechanisms would be expected to have weaker socket connections and thus be less secure during active gait than systems that include them. The purpose of this research was to develop and test a suspension system that allowed partial or complete doffing but did not require access to the socket, nor require the user to pull a cord taught during donning. A retractable tethered pin system was developed to operate with a normal shuttle lock suspension. Initial tests with prosthesis users were conducted.

Charting the future : Feedback from Prosthetics and Orthotics International readers and authors

People with transtibial amputation often experience skin breakdown due to the pressures and shear stresses that occur at the limb-socket interface. The purpose of this research was to create a transtibial finite element model (FEM) of a contemporary prosthesis that included complete socket geometry, two frictional interactions (limb-liner and liner-socket), and an elastomeric liner. Magnetic resonance imaging scans from three people with characteristic transtibial limb shapes (i.e., short-conical, long-conical, and cylindrical) were acquired and used to develop the models. Each model was evaluated with two loading profiles to identify locations of focused stresses during stance phase. The models identified five locations on the participants' residual limbs where peak stresses matched locations of mechanically induced skin issues they experienced in the 9 months prior to being scanned. The peak contact pressure across all simulations was 98 kPa and the maximum resultant shear stress was 50 kPa, showing reasonable agreement with interface stress measurements reported in the literature. Future research could take advantage of the developed FEM to assess the influence of changes in limb volume or liner material properties on interface stress distributions. Graphical abstract Residual limb finite element model. Left: model components. Right: interface pressures during stance phase.

People with lower limb amputation are unable to reliably sense ground characteristics due to compromised sensory inputs from the missing limb. As a result, they may rely on compensatory strategies, such as use of cognitive resources, when walking over complex surfaces. This study examined interactions between cognition and walking over a compliant surface in 14 people with transfemoral amputation (TFA) and 14 controls using a dual-task paradigm. Walking was assessed with quantitative motion analysis in both single-task (walking alone) and dual-task (walking while performing a cognitive task) conditions over a compliant foam surface. Outcomes were walking speed, step width, step time asymmetry, step time variability, and the speed and accuracy of cognitive task performance. For each outcome, effects of task (single-task, dual-task) and group (TFA, control) were examined with repeated-measures analysis of variance. No significant group-by-task interactions were observed for cognitive task performance. A significant group-by-task interaction for step time asymmetry indicated that participants with TFA increased temporal asymmetry in dual-task relative to single-task conditions, while control participants maintained symmetrical gait. The addition of a concurrent cognitive task did not differentially affect other aspects of gait between groups. Significant main effects of group for all walking outcomes indicated that participants with TFA walked slower, with wider, more asymmetric, and more variable steps than controls. Results suggest that gait quality degrades in challenging dual-task conditions for people with TFA, but not controls, consistent with the idea that people with TFA may use increased cognitive resources to control walking in complex environments.

Continuing education is intended to facilitate clinicians' skills and knowledge in areas of practice, such as administration and interpretation of outcome measures.To evaluate the long-term effect of continuing education on prosthetists' confidence in administering outcome measures and their perceptions of outcomes measurement in clinical practice.Pretest-posttest survey methods.A total of 66 prosthetists were surveyed before, immediately after, and 2 years after outcomes measurement education and training. Prosthetists were grouped as routine or non-routine outcome measures users, based on experience reported prior to training.On average, prosthetists were just as confident administering measures 1-2 years after continuing education as they were immediately after continuing education. In all, 20% of prosthetists, initially classified as non-routine users, were subsequently classified as routine users at follow-up. Routine and non-routine users' opinions differed on whether outcome measures contributed to efficient patient evaluations (79.3% and 32.4%, respectively). Both routine and non-routine users reported challenges integrating outcome measures into normal clinical routines (20.7% and 45.9%, respectively).Continuing education had a long-term impact on prosthetists' confidence in administering outcome measures and may influence their clinical practices. However, remaining barriers to using standardized measures need to be addressed to keep practitioners current with evolving practice expectations. Clinical relevance Continuing education (CE) had a significant long-term impact on prosthetists' confidence in administering outcome measures and influenced their clinical practices. In all, approximately 20% of prosthetists, who previously were non-routine outcome measure users, became routine users after CE. There remains a need to develop strategies to integrate outcome measurement into routine clinical practice.

To assess construct validity of the Prosthetic Limb Users Survey of Mobility (PLUS-M), a self-report mobility measure for people with lower limb amputation (LLA).Cross-sectional study.Private prosthetic clinics (n=37).Current lower limb prosthesis users (N=199; mean age ± SD, 55.4±14.3y; 71.4% men) were assessed before receiving a replacement prosthesis, prosthetic socket, and/or prosthetic knee.Not applicable.Convergent construct validity was examined using correlations between participants' PLUS-M T-scores and measures of physical function, mobility, and balance, including the Amputee Mobility Predictor (AMP), timed Up and Go (TUG), Patient-Reported Outcomes Measurement Information System-Physical Function (PROMIS-PF), Prosthesis Evaluation Questionnaire-Mobility Subscale (PEQ-MS), and Activities-specific Balance Confidence (ABC) Scale. Known-groups construct validity was evaluated by comparing differences in PLUS-M T-scores among participants grouped by Medicare Functional Classification Level (MFCL).PLUS-M T-scores demonstrated a moderate positive relationship with AMP scores (ρ=.54, P.001) and a moderate negative relationship with TUG times (ρ=-.56, P.001). The PLUS-M also showed a strong positive relationship with PEQ-MS scores (ρ=.78, P.001), ABC Scale scores (ρ=.81, P.001), and PROMIS-PF T-scores (ρ=.81, P.001). Significant differences (P.05) in PLUS-M T-scores were found among groups of people classified by different MFCLs.Study results support the validity of the PLUS-M as a self-report measure of prosthetic mobility. Correlations between PLUS-M and measures of physical function, mobility, and balance indicate convergent construct validity. Similarly, significant differences in PLUS-M T-scores across MFCL groups provide evidence of known-groups construct validity. In summary, evidence indicates that PLUS-M has good construct validity among people with LLA.