Effects of women's footwear on the mechanical function of heel-height accommodating prosthetic feet.
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ABSTRACT:
SUBMITTER: Major MJ
PROVIDER: S-EPMC8786192 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Many Service members and Veterans with lower-limb amputations have the potential for high function and the desire to resume physically demanding occupations that require them to carry heavy loads (e.g., military service, firefighters, farmers, ranchers, construction workers). However, it is currently unclear which prosthetic feet best accommodate heavy load carriage while also providing good overall function and mobility during unweighted activities. The main objective of this study was to investigate the ability of currently available prosthetic ankle-foot systems to accommodate weighted walking by examining the mechanical characteristics (i.e., forefoot stiffness) and dynamic function (i.e., rocker radius, effective foot length ratio, and late-stance energy return) of prosthetic feet designed for high activity users. Load versus deflection curves were obtained for nine prosthetic ankle-foot systems using a servohydraulic test frame and load cell. Effective roll-over shape characteristics and late-stance energy return measures were then obtained using quantitative gait analysis for three users with unilateral, transtibial amputation. Results from mechanical and dynamic testing showed that although forefoot stiffness varied across the nine feet investigated in this study, changes measured in roll-over shape radius and effective foot length ratio were relatively small in response to weighted walking. At the same time, prosthetic feet with more compliant forefoot keel structures appeared to provide more late-stance energy return compared to feet with stiffer forefoot keel structures. These results suggest that prosthetic ankle-foot systems with compliant forefoot keel structures may better accommodate weighted walking by reducing the metabolic cost of physically demanding activities. However, to more fully understand the biomechanical and functional implications of these results, other factors, such as the residual-limb strength of the user and the overall stiffness profile of the prosthetic foot, should also be considered.
| S-EPMC6135372 | biostudies-literature
Project description:BACKGROUND: Plantar heel pain is a common foot disorder aggravated by weight-bearing activity. Despite considerable focus on therapeutic interventions such as orthoses, there has been limited investigation of footwear-related issues in people with plantar heel pain. The aim of this study was to investigate whether people with plantar heel pain experience footwear-related difficulties compared to asymptomatic individuals, as well as identifying factors associated with footwear comfort, fit and choice. METHODS: The footwear domain of the Foot Health Status Questionnaire (FHSQ) was assessed in 192 people with plantar heel pain and 69 asymptomatic controls. The plantar heel pain group was also assessed on a variety of measures including: foot posture, foot strength and flexibility, pedobarography and pain level. A univariate analysis of covariance, with age as the covariate, was used to compare the heel pain and control groups on the FHSQ footwear domain score. A multiple regression model was then constructed to investigate factors associated with footwear scores among participants with plantar heel pain. RESULTS: When compared to asymptomatic participants, people with plantar heel pain reported lower FHSQ footwear domain scores (mean difference -24.4; p?<?0.001; 95 % CI: -32.0 to -17.0). In the participants with heel pain, footwear scores were associated with maximum force beneath the postero-lateral heel during barefoot walking, toe flexor strength and gender. CONCLUSIONS: People with plantar heel pain experience difficulty with footwear comfort, fit and choice. Reduced heel loading during barefoot walking, toe flexor weakness and female gender are all independently associated with reports of footwear difficulties in people with heel pain. Increased focus, in both clinical and research settings, is needed to address footwear-related issues in people with plantar heel pain.
| S-EPMC4539852 | biostudies-literature
Project description: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.
| S-EPMC9089881 | biostudies-literature
Project description:BackgroundHigh heel shoes (HHS) can affect human postural control because elevated heel height (HH) may result in plantar flexed foot and limit ankle joint range of motion during walking. Effects of HH and HHS wearing experience on postural stability during self-initiated and externally triggered perturbations are less examined in the literature. Hence, the objective of the present study is to investigate the influences of HH on human postural stability during dynamic perturbations, perceived stability, and functional mobility between inexperienced and experienced HHS wearers.MethodsA total of 41 female participants were recruited (21 inexperienced HHS wearers and 20 experienced HHS wearers). Sensory organization test (SOT), motor control test (MCT), and limits of stability (LOS) were conducted to measure participant's postural stability by using computerized dynamic posturography. Functional reach test and timed up and go test were performed to measure functional mobility. The participants' self-perceived stability was assessed by visual analog scale. Four pairs of shoes with different HH (i.e., 0.8, 3.9, 7.0, and 10.1 cm) were applied to participants randomly. Repeated measures analysis of variance was conducted to detect the effects of HH and HHS wearing experience on each variable.ResultsDuring self-initiated perturbations, equilibrium score remarkably decreased when wearing 10.1 cm compared with flat shoes and 3.9 cm HHS. The contribution of vision to postural stability was larger in 10.1 cm HHS than in flat shoes. The use of ankle strategy worsened when HH increased to 7 cm. Similarly, the directional control of the center of gravity (COG) decreased for 7 cm HHS in LOS. Experienced wearers showed significantly higher percentage of ankle strategy and COG directional control than novices. Under externally triggered perturbations, postural stability was substantially decreased when HH reached 3.9 cm in MCT. No significant difference was found in experienced wearers compared with novices in MCT. Experienced wearers exhibited considerably better functional mobility and perceived stability with increased HH.ConclusionsThe use of HHS may worsen dynamic postural control and functional mobility when HH increases to 3.9 cm. Although experienced HHS wearers exhibit higher proportion of ankle strategy and COG directional control, the experience may not influence overall human postural control. Sensory organization ability, ankle strategy and COG directional control might provide useful information in developing a safety system and prevent HHS wearers from falling.
| S-EPMC7602679 | biostudies-literature
Project description:BackgroundThe cost of losing foot health is significant to the person, healthcare systems, and economy, with diabetes related foot health issues alone costing over £1 billion annually in the UK. Yet many foot health problems are preventable through alternative health behaviour. It is therefore important to understand how feet, foot health and footwear are conceptualised to gain understanding about how these might influence foot health behaviour and inform health messages that seek to protect or improve foot health through altered health behaviour. This research seeks to explore attitudes and beliefs and identify phenomena that may act as barriers or motivators to the proactive self-management of foot health.MethodsPublic conversations involving 2,699 expressions related to feet, footwear or foot health on Facebook, Twitter, and Instagram were extracted. Conversations on Facebook and Twitter were scraped with NVivo's NCapture plugin whereby data is extracted and downloaded to NVivo. Extracted files were uploaded to the Big Content Machine (software developed at the University of Salford) which facilitated the search for keywords 'foot', 'feet', 'footwear', 'shoe', and 'shoes'. Instagram was scraped by hand. Data was analysed using a Thematic Analysis approach.ResultsThree themes were identified; 1) connections and disconnections derived from social and cultural constructs, 2) phenomena beyond attitudes and beliefs that relate to symbolic representations and the impact when foot health is lost, and 3) phenomena relating to Social Media as a conduit for the exploration of attitudes and beliefs.ConclusionsThis novel research exemplifies complex and sometimes incongruous perspectives about feet including their value for what they facilitate, contrasted with negative feelings about the negative impact that can have aesthetically when feet work hard. Sometimes feet were devalued, with expressions of disgust, disconnection, and ridicule. The importance of contextual, social, and cultural phenomena with implications for optimising foot health messages. Knowledge gaps including factors related to children's foot health and development, and how to treat foot health problems. The power of communities with shared experience to influence decisions, theories, and behaviour about foot health was also revealed. While people do talk about feet in some social contexts, it is not always in a way that promotes overt, positive foot health behaviour. Finally, this research demonstrates the benefit of exploring perspectives in uncontrived settings and illuminates the potential utility of social media (SoMe) platforms Facebook, Instagram, and Twitter as vehicles to promote foot health self-management behaviour that is responsive to the social and demographic variances of engagers who inhabit those spaces.
| S-EPMC10141949 | biostudies-literature
Project description:PurposeAccommodating intraocular lenses (A-IOLs) require capturing the ciliary muscle forces. Prior work demonstrated strong photo-initiated bonding between strips of capsular bag and poly(2-hydroxyethyl methacrylate); (pHEMA) polymer in an extraocular setting. We demonstrate that photobonding can be achieved intraocularly.MethodsPhacoemulsification was performed in porcine eyes (<24 hours postmortem). A commercial intraocular lens (IOL; pHEMA-MMA material) was inserted in the capsular bag. Surface contact between the lens and capsular bag was ensured by continuous air infusion into the anterior chamber of the eye, which provided sufficient pressure at the interface, as well as oxygen. The capsular bag and IOL then were stained with 0.1% photosensitizer Rose Bengal (RB) solution. A fiberoptic probe connected to a diode-laser (532 nm) was used to locally irradiate the capsular bag-IOL interface intraocularly. The bonding breaking load was evaluated in a uniaxial stretcher.ResultsPhotobonding occurred in the 0.8 to 1.6 W/cm2 irradiance range and 2.5 to 7 minutes irradiation time. Average forces of 0.12 N stretched but did not break the bond. These forces, applied uniaxially, are higher than the summed net accommodating force of the ciliary muscle along the entire equator (0.08 N). In two cases, the zonulae broke before the bonded region.ConclusionsPhotobonding between the capsular bag and IOL polymer can be achieved intraocularly, in a procedure compatible with standard cataract surgery. This technique will enable the mechanisms of A-IOLs not to rely on capsular bag integrity or natural haptic fibrosis.Translational relevanceIntraocular photobonding holds promise to enable operation of A-IOLs to restore accommodation in presbyopia, affecting 100% of the population >45 years old. Intraocular bonding of polymer material to ocular tissue also may find other applications in ophthalmology.
| S-EPMC6183327 | biostudies-literature
Project description:The aim of this study was to investigate whether accommodating elastic bands with barbell back squats (BSQ) increase muscular force during the deceleration subphase. Ten healthy men (mean ± standard deviation: Age: 23 ± 2 years; height: 170.5 ± 3.7 cm; mass: 66.7 ± 5.4 kg; and BSQ one repetition maximum (RM): 105 ± 23.1 kg; BSQ 1RM/body mass: 1.6 ± 0.3) were recruited for this study. The subjects performed band-resisted parallel BSQ (accommodating elastic bands each sides of barbell) with five band conditions in random order. The duration of the deceleration subphase, mean mechanical power, and the force and velocity during the acceleration and deceleration subphases were calculated. BSQ with elastic bands elicited greater mechanical power output, velocity, and force during the deceleration subphase, in contrast to that elicited with traditional free weight (p < 0.05). BSQ with elastic bands also elicited greater mechanical power output and velocity during the acceleration subphase. However, the force output during the acceleration subphase using an elastic band was lesser than that using a traditional free weight (p < 0.05). This study suggests that BSQ with elastic band elicit greater power output during the acceleration and deceleration subphases.
| S-EPMC6316108 | biostudies-literature
Project description:The mechanical behavior of the foot is often studied through the movement of the segments composing it and not through the movement of each individual bone, preventing an accurate and unambiguous study of soft tissue strains and foot posture. In order to describe the internal behavior of the foot under static load, we present here an original methodology that automatically tracks bone positions and ligament deformations through a series of CT acquisitions for a foot under load. This methodology was evaluated in a limited clinical study based on three cadaveric feet in different static load cases, first performed with bare feet and then with a sports shoe to get first insights on how the shoe influences the foot's behavior in different configurations. A model-based tracking technique using hierarchical distance minimization was implemented to track the position of 28 foot bones for each subject, while a mesh-morphing technique mapped the ligaments from a generic model to the patient-specific model in order to obtain their deformations. Comparison of these measurements between the ex vivo loaded bare foot and the shod foot showed evidence that wearing a shoe affects the deformation of specific ligaments, has a significant impact on the relative movement of the bones and alters the posture of the foot skeleton (plantar-dorsal flexion, arch sagging, and forefoot abduction-adduction on the midfoot). The developed method may provide new clinical indicators to guide shoe design and valuable data for detailed foot model validation.
| S-EPMC7316961 | biostudies-literature
Project description:Increasingly more young patients have been submitted to reconstruction of the Temporomandibular Joint (TMJ), so, the prostheses must to present more functional longevity.ObjectiveTo evaluate the effect of diamond-like carbon film (DLC) over titanium alloy (Ti6Al4V) and polyethylene (UHWPE) samples, their mechanical and chemical properties and cellular cytotoxicity.MethodsTitanium and UHWPE specimens, with 2.5 cm in diameter and 2 mm thickness were coated through plasma enhanced chemical vapor deposition (PECVD) with DLC or DLC doped with silver (DLC-Ag). Scanning electron microscopy (SEM) morphological analysis, Energy-dispersive spectroscopy (EDS) chemical analysis, scratching test, mechanical fatigue test, surface roughness analysis, and cellular cytotoxicity were performed. Data were statistically analyzed using one-way ANOVA (p < 0.05) or two-way ANOVA and multiple comparison Tukey test.ResultsIn the SEM analysis, morphological differences were observed on substrates after DLC deposition. The film chemically modified the substrate surfaces, according to the EDS analysis. The initial critical load failure occurred at 6.1 N for DLC and 9.7 N for the DLC-Ag film. The DLC film deposition over the polyethylene promoted a decrease in the polymer's damaged area after mechanical fatigue cycling. The cytotoxicity analysis demonstrated less biocompatibility in experimental groups, when compared to control, however, increased biocompatibility was observed, at 10 days, in all groups.ConclusionThe diamond-like carbon coating enhanced the chemical and mechanical properties from substrates, however modified biological interaction course of the titanium alloy (Ti6Al4V) and polyethylene (UHWPE) samples. Parameters for film deposition remain to be improved in order to obtain best biocompatibility.
| S-EPMC6510974 | biostudies-literature
Project description:In this study, we analyzed the influence of prosthetic abutment height on marginal bone loss (MBL) around implants in the posterior maxilla. In this retrospective cohort study, the radiographically determined MBL was related to the height of the abutments of internal conical connection implants at 6 and 18 months post-loading. Data were gathered on age, sex, bone substratum, smoking habit, history of periodontitis, and prosthetic features, among other variables. A linear mixed model was used for statistical analysis. The study included 131 patients receiving 315 implants. MBL rates at 6 and 18 months were mainly affected by the abutment height but were also significantly influenced by the bone substratum, periodontitis, and smoking habit. MBL rates were higher for prosthetic abutment < 2 mm vs. ≥ 2 mm, for periodontal vs. non-periodontal patients, for grafted vs. pristine bone, and for a heavier smoking habit. The abutment height is a key factor in MBL. MBL rates followed a non-linear trend, with a greater MBL rate during the first 6 months post-loading than during the next 12 months.
| S-EPMC4293716 | biostudies-literature