Dataset Information

Using mechanical testing to assess the effect of lower-limb prosthetic socket texturing on longitudinal suspension.

ABSTRACT: To function effectively, a lower limb prosthetic socket must remain securely coupled to the residual limb during walking, running and other activities of daily living; this coupling is referred to as suspension. When this coupling is insufficient longitudinal pistoning of the socket relative to the residual limb occurs. Increasing friction of the socket/liner interface may improve socket suspension and textured sockets may be fabricated relatively easily with 3D printing. The aim of this study was to investigate longitudinal displacement of sockets with different types of textures under two suspension conditions: passive suction and active vacuum. In order to do this, we developed a mock residual limb and mechanical testing protocol. Prosthetic sockets, 14 textured sockets and an Original Squirt-Shape (OSS) Socket, were fabricated from polypropylene copolymer using the Squirt-Shape™ 3D Printer and compared to a smooth socket thermoformed from polypropylene copolymer. Sockets were mounted onto a dual durometer mock residual limb and subjected to four levels of distraction forces (100 N, 250 N, 500 N and 650 N) using a hydraulic material testing system. There was a statistically significant three-way interaction between suspension, force level and texture (p < 0.0005). Longitudinal displacements between textured and reference sockets, for all force levels and both suspension conditions, were significantly different (p < 0.0005). Using these newly developed mechanical testing protocols, it was demonstrated that texturing of polypropylene copolymer sockets fabricated using Squirt-Shape significantly decreased longitudinal displacements compared to a smooth socket. However, none of the novel textured sockets significantly reduced longitudinal displacement compared to the OSS socket under passive suction suspension.

SUBMITTER: Quinlan J

PROVIDER: S-EPMC7437898 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Using mechanical testing to assess the effect of lower-limb prosthetic socket texturing on longitudinal suspension.

Quinlan Julia J Yohay Jessica J Subramanian Vasanth V Poziembo Brad B Fatone Stefania S

PloS one 20200819 8

To function effectively, a lower limb prosthetic socket must remain securely coupled to the residual limb during walking, running and other activities of daily living; this coupling is referred to as suspension. When this coupling is insufficient longitudinal pistoning of the socket relative to the residual limb occurs. Increasing friction of the socket/liner interface may improve socket suspension and textured sockets may be fabricated relatively easily with 3D printing. The aim of this study w ...[more]

PMID: 32813733

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Project description:Creating a secure and comfortable linkage between the residual limb and prosthetic socket in persons with lower limb amputation is a critical factor for successful rehabilitation, including ambulation and other activities of daily living. Unwanted rotation within the socket can be a clinical problem for prosthesis users. One way of addressing issues experienced with transverse plane control of the socket may be through increased friction interface forces. It has been proposed that friction at the residual limb/socket interface may be increased by adding texture to interface components. Three-dimensional (3D) printing may be used to fabricate sockets with texture patterns added to the inner socket surface. Hence, the aim of this study was to investigate the effects of socket texturing on transverse plane rotation of the socket on a mock residual limb under two suspension conditions: passive suction and active vacuum. To conduct this study, we developed a mechanical testing protocol as no standardized tests currently exist to assess prosthetic sockets. Sockets with 14 different texture patterns were fabricated using the Squirt-Shape™ 3D printer. Textured sockets were compared to an Original Squirt-Shape (OSS) socket and a smooth thermoformed socket. Sockets were fitted with a mock residual limb and bi-axially loaded to 350 N compression with simultaneous rotation (2.5°, 5° and 7.5°) using a custom rotation assembly attached to a uniaxial hydraulic material testing system. There was a statistically significant three-way interaction between suspension, angle and texture (p < 0.0005). Torques between textured and reference sockets, for all rotation angles and both suspension conditions, were significantly different (p < 0.0005). Using newly developed testing protocols, it was demonstrated that some texture patterns significantly increased torque (i.e., resistance against unwanted rotation) in the transverse plane compared to both OSS and smooth sockets, especially for passive suction. Rotation testing of sockets may provide insight into socket design to improve suspension in the transverse plane.

Project description:ObjectiveTo evaluate test-retest reliability and related measurement properties of items developed to assess best, worst, and average prosthetic socket comfort.DesignMethodological research to assess test-retest reliability of 4 individual socket comfort survey items. Socket comfort items were included in a self-report paper survey, which was administered to participants 2 to 3 days apart.SettingGeneral community.ParticipantsA minimum convenience sample of participants (N=63) was targeted for this study; 72 lower limb prosthesis users (>1y postamputation) completed the survey and were included in the final dataset.InterventionsNot applicable.Main outcome measureThe 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 7 days.ResultsBest, worst, and average socket comfort items demonstrated better reliability, as indicated by higher intraclass 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 4 ESCS items were below the level desired for evaluation of within-individual changes of socket comfort.ConclusionsItems that assess best, worst, and average comfort provide a more stable measurement of socket fit than the existing SCS instrument. Although administration of all 4 ESCS items may provide more comprehensive assessment of a lower limb prosthesis user's socket fit, administrators should expect variations in scores over time owing to the variable nature of the underlying construct over time. Future research should examine whether the ESCS provides an improved overall assessment of socket fit.

Project description:BackgroundAchieving 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.ObjectiveTo develop a brief, clinically meaningful, and psychometrically robust PROM to measure prosthetic mobility.DesignA 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.SettingParticipants were recruited using flyers posted in hospitals and prosthetics clinics across the United States, magazine advertisements, notices posted to consumer websites, and direct mailings.ParticipantsAdult prosthesis users (N = 1091) with unilateral lower limb amputation due to traumatic or dysvascular causes.InterventionsNot applicable.Main outcome measuresCandidate 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.ResultsA 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.ConclusionThe 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.

Project description:ObjectiveTo 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).DesignCross-sectional study.SettingPrivate prosthetic clinics (n=37).ParticipantsCurrent 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.InterventionsNot applicable.Main outcome measuresConvergent 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).ResultsPLUS-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.ConclusionsStudy 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.

Project description:PurposeThis study sought to measure and identify factors associated with satisfaction with care among veterans. The metrics were colelcted for those receiving prosthetic limb care at the US Department of Veterans Affairs (VA) and US Department of Defense (DoD) care settings and at community-based care providers.MethodsA longitudinal cohort of veterans with major upper limb amputation receiving any VA care from 2010 to 2015 were interviewed by phone twice, 1 year apart. Care satisfaction was measured by the Orthotics and Prosthetics User's Survey (OPUS) client satisfaction survey (CSS), and prosthesis satisfaction was measured by the OPUS client satisfaction with device (CSD), and the Trinity Amputation and Prosthetic Experience Scale satisfaction scales. The Quality of Care index, developed for this study, assessed care quality. Bivariate analyses and multivariable linear regressions identified factors associated with CSS. Wilcoxon Mann-Whitney rank tests and Fisher exact tests compared CSS and Quality of Care items at follow-up for those with care within and outside of the VA and DoD.ResultsThe study included 808 baseline participants and 585 follow-up participants. Device satisfaction and receipt of amputation care in the prior year were associated with greater satisfaction with care quality. Persons with bilateral amputation were significantly less satisfied with wait times. Veterans who received amputation care in the VA or DoD had better, but not statistically different, mean (SD) CSS scores: 31.6 (22.6) vs 39.4 (16.9), when compared with those who received care outside the VA or DoD. Those with care inside the VA or DoD were also more likely to have a functional assessment in the prior year (33.7% vs 7.1%, P = .06), be contacted by providers (42.7% vs 18.8%, P = .07), and receive amputation care information (41.6% vs 0%, P =.002). No statistically significant differences in CSS, Quality of Care scores, or pain measures were observed between baseline and follow-up. In regression models, those with higher CSD scores and with prior year amputation care had higher satisfaction when compared to those who had not received care.ConclusionsSatisfaction with prosthetic limb care is associated with device satisfaction and receipt of care within the prior year. Veterans receiving amputation care within the VA or DoD received better care quality scores than those receiving prosthetic care outside of the VA or DoD. Satisfaction with care and quality of care were stable over the 12 months of this study. Findings from this study can serve as benchmarks for future work on care satisfaction and quality of amputation rehabilitative care.

Dataset Information

Using mechanical testing to assess the effect of lower-limb prosthetic socket texturing on longitudinal suspension.

Publications

Using mechanical testing to assess the effect of lower-limb prosthetic socket texturing on longitudinal suspension.

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