Impact of mobile phone use on accidental falls risk in young adult pedestrians.

Background: Mobile phone use is known to be a distraction to pedestrians, increasing their likelihood of crossing into oncoming traffic or colliding with other people. However, the effect of using a mobile phone to text while walking on gait stability and accidental falls in young adults remains inconclusive. This study uses a 70 cm low friction slip hazard and the threat of hazard to investigate the effects of texting while walking on gait stability, the ability to recover balance after a slip hazard and accidental falls. Methods: Fifty healthy young adults performed six walking tasks, and one seated texting task in random order. The walks were conducted over a 10-m walkway. Four progressive hazard levels were used: 1) Seated; 2) Normal Walk (walking across the walkway with no threat of a slip); 3) Threat (walking with the threat of a slip); and 4) Slip (walking with an actual 70 cm slip hazard). The three walking conditions were repeated twice with and without the mobile phone texting dual-task. Gait kinematics and trunk posture were recorded using wearable sensors attached to the head, trunk, pelvis and feet. Study outcomes were analyzed using repeated measures analysis of variance with significance set to P≤.05. Results: Mobile phone use significantly impaired postural balance recovery when slipping, as demonstrated by increased trunk sway. Mobile phone use negatively impacted gait stability as demonstrated by increased step time variability and decreased harmonic ratios. Increased hazard levels also led to reduced texting accuracy. Conclusions: Using a mobile phone to text while walking may compete with locomotor tasks, threat assessment and postural balance control mechanisms, which leads to an increased risk of accidental falls in young adults. Pedestrians should therefore be discouraged through new educational and technology-based initiatives (for example a "texting lock" on detection of walking) from texting while walking on roadside footpaths and other environments where substantial hazards to safety exist.

Validation of a Custom Interface Pressure Measurement System to Improve Fitting of Transtibial Prosthetic Check Sockets.

Achievement of fit between the residual limb and prosthetic socket during socket manufacture is a priority for clinicians and is essential for safety. Clinicians have recognised the potential benefits of having a sensor system that can provide objective socket-limb interface pressure measurements during socket fitting, but the cost of existing systems makes current technology prohibitive. This study will report on the characterisation, validation and preliminary clinical implementation of a low cost, portable, wireless sensor system designed for use during socket manufacture. Characterisation and benchtop testing demonstrated acceptable accuracy, behaviour at variable temperature, and dynamic response for use in prosthetic socket applications. Our sensor system was validated with simultaneous measurement by a commercial sensor system in the sockets of three transtibial prosthesis users during a fitting session in the clinic. There were no statistically significant differences between the sensor system and the commercial sensor for a variety of functional activities. The sensor system was found to be valid in this clinical context. Future work should explore how pressure data relates to ratings of fit and comfort, and how objective pressure data might be used to assist in clinical decision making.

Transtibial prosthetic socket fitting: Australian prosthetist perspectives on primary challenges, management strategies, and opportunities for workflow and technological innovation.

BACKGROUND: Following transtibial amputation, a custom-built socket is the most common interface between the prosthesis and residual limb. Desire from both prosthetists and prosthesis users for improved socket fitting processes have been well documented. However, there is currently limited information available about prosthetists' experiences of how prosthetic manufacturing workflow can contribute to socket fit problems. OBJECTIVES: This study aims to determine how socket fit problems are currently detected and managed by prosthetists and to identify challenges, management strategies, and opportunities for workflow and technological innovation during prosthesis manufacture and socket fitting. STUDY DESIGN: Mixed-method (quantitative and qualitative) survey. METHODS: An online survey was developed and piloted in consultation with members of the Australian Orthotic Prosthetic Association. The final 25-question survey was distributed through their membership database. Mixed methods were used to analyze survey items. Qualitative items were grouped and coded under themes relating to challenges, management strategies, and opportunities. Quantitative data were analyzed using nonparametric descriptive methods. RESULTS: Twenty-three respondents with a range of experience completed the survey. Seven of eight major Australian states/territories were represented. Primary workflow stages presenting challenges with limited strategies/solutions available to the prosthetists were roll-on liner selection, mold or cast modifications, communication with the client, and check socket fitting. Suggested solutions included improved socket-limb interface monitoring technology. CONCLUSIONS: This study provides the first insights into prosthetist-identified challenges and limitations at different stages of the socket workflow and presents a starting point for more targeted research into innovation that may assist in these processes.

Estimating Lower Limb Kinematics Using a Reduced Wearable Sensor Count.

GOAL: This paper presents an algorithm for accurately estimating pelvis, thigh, and shank kinematics during walking using only three wearable inertial sensors. METHODS: The algorithm makes novel use of a constrained Kalman filter (CKF). The algorithm iterates through the prediction (kinematic equation), measurement (pelvis position pseudo-measurements, zero velocity update, flat-floor assumption, and covariance limiter), and constraint update (formulation of hinged knee joints and ball-and-socket hip joints). RESULTS: Evaluation of the algorithm using an optical motion capture-based sensor-to-segment calibration on nine participants (7 men and 2 women, weight [Formula: see text] kg, height [Formula: see text] m, age [Formula: see text] years old), with no known gait or lower body biomechanical abnormalities, who walked within a [Formula: see text] m 2 capture area shows that it can track motion relative to the mid-pelvis origin with mean position and orientation (no bias) root-mean-square error (RMSE) of [Formula: see text] cm and [Formula: see text], respectively. The sagittal knee and hip joint angle RMSEs (no bias) were [Formula: see text] and [Formula: see text], respectively, while the corresponding correlation coefficient (CC) values were [Formula: see text] and [Formula: see text]. CONCLUSION: The CKF-based algorithm was able to track the 3D pose of the pelvis, thigh, and shanks using only three inertial sensors worn on the pelvis and shanks. SIGNIFICANCE: Due to the Kalman-filter-based algorithm's low computation cost and the relative convenience of using only three wearable sensors, gait parameters can be computed in real-time and remotely for long-term gait monitoring. Furthermore, the system can be used to inform real-time gait assistive devices.

Clinical utility of pressure feedback to socket design and fabrication.

BACKGROUND: The clinical utility of measuring pressure at the prosthetic socket-residual limb interface is currently unknown. OBJECTIVES: This study aimed to identify whether measuring interface pressure during prosthetic design and fabrication results in closer agreement in pressure measurements between sockets made by different clinicians, and a reduction in pressure over areas of concern. It also investigated whether clinicians value knowing the interface pressure during the fabrication process. STUDY DESIGN: Mixed methods. METHODS: Three prosthetists designed a complete prosthetic system for a transtibial residual limb surrogate. Standardised mechanical testing was performed on each prosthetic system to gain pressure measurements at four key anatomical locations. These measurements were provided to the clinicians, who subsequently modified their sockets as each saw fit. The pressure at each location was re-measured. Each prosthetist completed a survey that evaluated the usefulness of knowing interface pressures during the fabrication process. RESULTS: Feedback and subsequent socket modifications saw a reduction in the pressure measurements at three of the four anatomical locations. Furthermore, the pressure measurements between prosthetists converged. All three prosthetists found value in the pressure measurement system and felt they would use it clinically. CONCLUSIONS: Results suggest that sensors measuring pressure at the socket-limb interface has clinical utility in the context of informing prosthetic socket design and fabrication. If the technology is used at the check socket stage, iterative designs with repeated measurements can result in increased consistency between clinicians for the same residual limb, and reductions in the magnitudes of pressures over specific anatomical landmarks. CLINICAL RELEVANCE: This study provides new information on the value of pressure feedback to the prosthetic socket design process. It shows that with feedback, socket modifications can result in reduced limb pressures, and more consistent pressure distributions between prosthetists. It also justifies the use of pressure feedback in informing clinical decisions.

Reliability and Validity of Measurement Tools for Residual Limb Volume in People With Limb Amputations: A Systematic Review.

BACKGROUND: Measurements of residual limb volume often guide decisions on the type and timing of prosthetic prescription. To help inform these decisions, it is important that clinicians use measurement tools that are reliable and valid. PURPOSE: The aim of this systematic review was to investigate the reliability and validity of measurement tools for residual limb volume in people with limb amputations. DATA SOURCES: A comprehensive search on MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science was performed on July 11, 2016. STUDY SELECTION: Studies were included if they examined the reliability or validity of measurement tools for residual limb volume, were conducted on humans, and were published in English. DATA EXTRACTION: Data were extracted from 11 reliability and 4 validity studies and included study characteristics, volumetric estimates, and reliability and validity estimates. The quality of the studies was also rated. DATA SYNTHESIS: Data from 2 studies (38 participants) indicated good to excellent intrarater (intraclass correlation coefficient [ICC] ≥0.88) and interrater (ICC ≥0.88) reliability and high between-session reliability (coefficient of variation [CV] = 10%) for water displacement volumetry. One study (28 participants) reported excellent intrarater and interrater reliability (ICC ≥0.93) for the circumferential method, and data from 2 studies (19 participants) indicated high between-session reliability for the optical surface scanner (CV ≤9.8%). Three studies (26 participants) indicated good to excellent between-session reliability results for computed tomography (CV = 9.2%-10.9%). One study (7 participants) showed moderate within-session reliability (CV = 50%). Using water displacement volumetry as the gold standard, 2 studies (79 participants) indicated excellent validity for the circumferential method ( r ≥0.92; ICC ≥0.92). All studies reporting measures of reliability or validity were performed with people who had transtibial amputations. LIMITATIONS: Only studies published in English and in which water displacement volumetry was used as the gold standard were included in this review. The reliability and validity of the quality rating scale used in this review have not been tested. CONCLUSIONS: On the basis of a limited number of moderate- to high-quality studies with small sample sizes, circumferential and water displacement methods were found to be reliable, and the circumferential method was found to be valid in people with transtibial amputations. There are inadequate data for drawing conclusions about volume measurement methods in people with other types of limb amputations.

Reliability and validity of the iSense optical scanner for measuring volume of transtibial residual limb models.

BACKGROUND:: Residual limb volume is often measured as part of routine care for people with amputations. These measurements assist in the timing of prosthetic fitting or replacement. In order to make well informed decisions, clinicians need access to measurement tools that are valid and reliable. OBJECTIVES:: To assess the reliability and criterion validity of the iSense optical scanner in measuring volume of transtibial residual limb models. STUDY DESIGN:: Three assessors performed two measurements each on 13 residual limb models with an iSense optical scanner (3D systems, USA). Intra-rater and inter-rater reliability were calculated using intraclass correlation coefficients. Bland Altman plots were inspected for agreement. Criterion validity was assessed using a steel rod of known dimensions. Ten repeated measurements were performed by one assessor. A t-test was used to determine differences between measured and true rod volume. RESULTS:: Intra-rater reliability was excellent (range of intraclass correlation coefficients: 0.991-0.997, all with narrow 95% confidence intervals). While the intraclass correlation coefficients suggest excellent inter-rater reliability between all three assessors (range of intraclass correlation coefficients: 0.952-0.986), the 95% confidence intervals were wide between assessor 3 and the other two assessors. Poor agreement with assessor 3 was also seen in the Bland-Altman plots. Criterion validity was very poor with a significant difference between the mean iSense measurement and the true rod volume (difference: 221.18 mL; p < 0.001). CONCLUSIONS:: Although intra-rater reliability was excellent for the iSense scanner, we did not find similar results for inter-rater reliability and validity. These results suggest that further testing of the iSense scanner is required prior to use in clinical practice. CLINICAL RELEVANCE: The iSense offers a low cost scanning option for residual limb volume measurement. Intra-rater reliability was excellent, but inter-rater reliability and validity were such that clinical adoption is not indicated at present.

Differences Between Gait on Stairs and Flat Surfaces in Relation to Fall Risk and Future Falls.

We used body-worn inertial sensors to quantify differences in semi-free-living gait between stairs and on normal flat ground in older adults, and investigated the utility of assessing gait on these terrains for predicting the occurrence of multiple falls. Eighty-two community-dwelling older adults wore two inertial sensors, on the lower back and the right ankle, during several bouts of walking on flat surfaces and up and down stairs, in between rests and activities of daily living. Derived from the vertical acceleration at the lower back, step rate was calculated from the signal's fundamental frequency. Step rate variability was the width of this fundamental frequency peak from the signal's power spectral density. Movement vigor was calculated at both body locations from the signal variance. Partial Spearman correlations between gait parameters and physiological fall risk factors (components from the Physiological Profile Assessment) were calculated while controlling for age and gender. Overall, anteroposterior vigor at the lower back in stair descent was lower in subjects with longer reaction times. Older adults walked more slowly on stairs, but they were not significantly slower on flat surfaces. Using logistic regression, faster step rate in stair descent was associated with multiple prospective falls over 12 months. No significant associations were shown from gait parameters derived during walking upstairs or on flat surfaces. These results suggest that stair descent gait may provide more insight into fall risk than regular walking and stair ascent, and that further sensor-based investigation into unsupervised gait on different terrains would be valuable.

Mechanical characterization and comparison of energy storage and return prostheses.

The suitability of finite element analysis (FEA) for standardizing the mechanical characterization of energy storage and return (ESAR) prostheses was investigated. A methodology consisting of both experimental and numerical analysis was proposed and trialed for the Vari-flex® ModularTM, Flex-foot Cheetah and Cheetah Xtreme by Össur® and a 1E90 Sprinter by Ottobock®. Gait analysis was conducted to determine suitable orientation angles for non-destructive testing (NDT) of the ESAR prostheses followed by a quasi-static inverse FEA procedure within COMSOL Multiphysics®, where the NDT conditions were replicated to determine the homogenized material properties of the prostheses. The prostheses' loading response under bodyweight for an 80kg person was then simulated, using both Eigenfrequency and time-dependent analysis. The apparent stiffness under bodyweight was determined to be 94.7, 48.6, 57.4 and 65.0Nmm-1 for the Vari-flex® ModularTM, Flex-foot Cheetah, Cheetah Xtreme and 1E90 Sprinter, respectively. Both the energy stored and returned by the prostheses varied negatively with stiffness, yet the overall efficiency of the prostheses were similar, at 52.7, 52.0, 51.7 and 52.4% for the abovementioned prostheses. The proposed methodology allows the standardized assessment and comparison of ESAR prostheses without the confounding influences of subject-specific gait characteristics.

A prosthesis-specific multi-link segment model of lower-limb amputee sprinting.

Lower-limb amputees commonly utilize non-articulating energy storage and return (ESAR) prostheses for high impact activities such as sprinting. Despite these prostheses lacking an articulating ankle joint, amputee gait analysis conventionally features a two-link segment model of the prosthetic foot. This paper investigated the effects of the selected link segment model׳s marker-set and geometry on a unilateral amputee sprinter׳s calculated lower-limb kinematics, kinetics and energetics. A total of five lower-limb models of the Ottobock® 1E90 Sprinter were developed, including two conventional shank-foot models that each used a different version of the Plug-in-Gait (PiG) marker-set to test the effect of prosthesis ankle marker location. Two Hybrid prosthesis-specific models were then developed, also using the PiG marker-sets, with the anatomical shank and foot replaced by prosthesis-specific geometry separated into two segments. Finally, a Multi-link segment (MLS) model was developed, consisting of six segments for the prosthesis as defined by a custom marker-set. All full-body musculoskeletal models were tested using four trials of experimental marker trajectories within OpenSim 3.2 (Stanford, California, USA) to find the affected and unaffected hip, knee and ankle kinematics, kinetics and energetics. The geometry of the selected lower-limb prosthesis model was found to significantly affect all variables on the affected leg (p < 0.05), and the marker-set also significantly affected all variables on the affected leg, and none of the unaffected leg variables. The results indicate that the omission of prosthesis-specific spatial, inertial and elastic properties from full-body models significantly affects the calculated amputee gait characteristics, and we therefore recommend the implementation of a MLS model.

Quantifying prosthetic gait deviation using simple outcome measures.

AIM: To develop a subset of simple outcome measures to quantify prosthetic gait deviation without needing three-dimensional gait analysis (3DGA). METHODS: Eight unilateral, transfemoral amputees and 12 unilateral, transtibial amputees were recruited. Twenty-eight able-bodied controls were recruited. All participants underwent 3DGA, the timed-up-and-go test and the six-minute walk test (6MWT). The lower-limb amputees also completed the Prosthesis Evaluation Questionnaire. Results from 3DGA were summarised using the gait deviation index (GDI), which was subsequently regressed, using stepwise regression, against the other measures. RESULTS: Step-length (SL), self-selected walking speed (SSWS) and the distance walked during the 6MWT (6MWD) were significantly correlated with GDI. The 6MWD was the strongest, single predictor of the GDI, followed by SL and SSWS. The predictive ability of the regression equations were improved following inclusion of self-report data related to mobility and prosthetic utility. CONCLUSION: This study offers a practicable alternative to quantifying kinematic deviation without the need to conduct complete 3DGA.

Energy Storage and Return Prostheses: A Review of Mechanical Models.

Conventional lower-limb mechanical models were originally developed for gait analysis of ablebodied Conventional lower-limb mechanical models were originally developed for gait analysis of ablebodied subjects and therefore potentially misrepresent prosthetic foot behavior when applied to modern energy storage and return (ESAR) prostheses. This review investigates the limitations of current models of prosthetic foot dynamics and kinematics. The Scopus online database was used to identify 236 articles on prosthetic foot behavior during either experiments or simulations, categorized into three main types of models: 74% (n = 175) of studies featured a rigid-link model, 17% (n = 39) a lumped-parameter model and 10% (n = 23) finite element (FE) analysis. Notably, 64% (n = 152) of the studies used a conventional two-link segment model, yet only 8% (n = 20) featured the rigid, articulating prosthesis that satisfies this model's underlying rigid-body mechanics assumptions. Conversely, the available preliminary studies on multi-link segment, lumped-parameter and FE models present viable and more mechanically relevant alternatives to conventional techniques, particularly for ESAR prostheses. Expanding these alternative models to include inertial behavior, multiple-degrees of freedom and standardization of boundary conditions will lead towards both accurate and standardized prosthetic foot analysis.

The Hemodynamic Effects of Hemodialysis Needle Rotation and Orientation in an Idealized Computational Model.

Maintaining the patency of vascular access is essential for performing efficient hemodialysis. Appropriate cannulation technique is critical in maintaining the integrity of vascular access. This study focused on analyzing the hemodynamic effect of needle rotation, which is performed to alleviate the pressure if the needle becomes attached to the blood vessel wall. The hemodynamic benefits (normal wall shear stress [WSS] and smooth flow with no oscillatory motion) of this technique are investigated in an idealized model of the cephalic vein in order to determine a needle position that will reduce conditions known to contribute to vascular access failure. A computational fluid dynamics study was conducted, with antegrade and retrograde orientations simulated on the arterial needle, whereas the venous needle is placed in the antegrade orientation. In every case, needle rotation offered no hemodynamic benefit in minimizing the conditions known to cause endothelial damage, a precursor to vascular access failure. Venous needle rotation reduced the maximum WSS by 30%. However, the WSS was above the range, which may damage the endothelial layer. The arterial needle in the antegrade orientation produced a large region of oscillatory shear, whereas a retrograde orientation produced a region of smooth flow in the vicinity of the needle with only a small region of oscillatory shear. The flow through the venous needle back eye was negligible, whereas the arterial needle back eye was more efficient in the retrograde orientation. Therefore, the venous needle should not be rotated, whereas the arterial needle may be rotated to alleviate pressure with consideration given to the orientation of the needle.

Concurrent multibody and Finite Element analysis of the lower-limb during amputee running.

Lower-limb amputee athletes use Carbon fiber Energy Storage and Return (ESAR) prostheses during high impact activities such as running. The advantage provided to amputee athletes due to the energy-storing properties of ESAR prostheses is as yet uncertain. Conventional energy analysis methods for prostheses rely upon multibody models with articulating joints. Alternatively, Finite Element (FE) analysis treats bodies as a deforming continuum and can therefore calculate the energy stored without using these rigid-body mechanics assumptions. This paper presents a concurrent multibody and FE model of the femur, tibia, socket and ESAR prosthesis of a transtibial amputee athlete during sprinting. Gait analysis spatial data was used to conduct an offline simulation of the affected leg's stance phase in COMSOL Multiphysics. The calculated peak elastic strain energy of the prosthesis was 80J, with an overall RMSE of simulated marker displacement of 4.19 mm. This concurrent model presents a novel method for analyzing in vivo ESAR prosthesis behavior.

Instrumented and interactive limb models for biomechanics education: An assessment of efficacy and engagement.

Custom anatomical and instrumented models of the human arm and leg were designed and manufactured to complement the teaching of introductory biomechanics subjects. The models were assessed for engagement and efficacy via questionnaires and unscheduled pop-quizzes, respectively. Questionnaire results demonstrated the ability of the models to provide assistance with understanding and visualising the fundamental principles of biomechanics. Additionally, the majority of students who participated also stated that the models enhanced their motivation to learn and stimulated their interest in biomechanics. Results from the pop-quizzes were ambiguous about the efficacy of the arm and leg models; only one group (out of five) showed significant improvements in pop-quiz scores following exposure to the models. Significance was not reached in the remaining groups. Further assessment is required to expose the true efficacy of the models.

An eight-legged tactile sensor to estimate coefficient of static friction.

It is well known that a tangential force larger than the maximum static friction force is required to initiate the sliding motion between two objects, which is governed by a material constant called the coefficient of static friction. Therefore, knowing the coefficient of static friction is of great importance for robot grippers which wish to maintain a stable and precise grip on an object during various manipulation tasks. Importantly, it is most useful if grippers can estimate the coefficient of static friction without having to explicitly explore the object first, such as lifting the object and reducing the grip force until it slips. A novel eight-legged sensor, based on simplified theoretical principles of friction is presented here to estimate the coefficient of static friction between a planar surface and the prototype sensor. Each of the sensor's eight legs are straight and rigid, and oriented at a specified angle with respect to the vertical, allowing it to estimate one of five ranges (5 = 8/2 + 1) that the coefficient of static friction can occupy. The coefficient of friction can be estimated by determining whether the legs have slipped or not when pressed against a surface. The coefficients of static friction between the sensor and five different materials were estimated and compared to a measurement from traditional methods. A least-squares linear fit of the sensor estimated coefficient showed good correlation with the reference coefficient with a gradient close to one and an r(2) value greater than 0.9.

In vitro mechanical testing of braided polyurethane elastic fiber and braided polyester for equine laryngoplasty.

OBJECTIVES: In vitro comparison of the mechanical properties of braided polyurethane elastomer (Lycra®) and braided polyester (Ethibond™) (1) when inserted into the muscular process of the arytenoid cartilage and (2) as suture loops. STUDY DESIGN: Experimental. ANIMALS: Equine cadaver larynges (n = 15). METHODS: The muscular processes (n = 30) of the arytenoid cartilages were dissected from each larynx and embedded in a resin base. Lycra® and Ethibond™ prostheses were randomly allocated to the left or right muscular process and each underwent cyclic fatigue (25-50 N) followed by load-to-failure testing. Isolated suture loops of Lycra® (n = 25) and Ethibond™ (n = 25) also underwent the same cyclic fatigue followed by load-to-failure testing (n = 20) or a creep testing protocol (25 N for 10 min; n = 5). RESULTS: Lycra® prostheses pulled through the cartilage in a significantly greater proportion of cyclic tests (P = .015) and at lower mean (±SD) loads, (95.9 ± 23.4 N) during load-to-failure testing than Ethibond™ prostheses (155.2 ± 24.4 N; P = .0041). Lycra® had a significantly greater displacement with and without a cartilage interface when compared to Ethibond™ (P < .001, P < .002). The Lycra® isolated suture loops failed at significantly greater loads (233.0 ± 38.7 N) during load-to-failure testing than Ethibond™ loops (201.6 ± 47.4 N; P = .042). CONCLUSIONS: Lycra® prostheses embedded in laryngeal cartilage pulled through the cartilage at lower loads than Ethibond™ prostheses. Lycra® suture loops were stronger than Ethibond™ suture loops. Lycra® had greater displacement than Ethibond™ in all tests as suture loops or when embedded in cartilage.

Use of gait summary measures with lower limb amputees.

Gait summary measures have been developed as a convenient method to communicate overall gait pathology. These measures are primarily used in the context of paediatric cerebral palsy and their use remains largely untested in other disability groups. This study assessed the suitability of gait summary measures for use with lower limb amputees. Modified (m) versions of three published gait summary measures were investigated - the Gillette Gait Index (mGGI), the Gait Deviation Index (mGDI) and the Gait Profile Score (mGPS) in conjunction with the Movement Analysis Profile (MAP). Twenty unilateral lower limb amputees underwent three-dimensional gait analysis. All measures reported significant differences between levels of amputation on the prosthetic limb. The mGGI and mGPS detected significant differences between the levels of amputation on the intact side, but the mGDI did not. All gait summary measures were moderately to strongly correlated with leg-length normalised self-selected walking speed and strong correlations were reported between all measures. The MAP exposed common strategies in amputee gait and showed that sagittal hip and knee kinematics contributed predominantly to overall gait deviation in this population group. The mGGI, mGDI and mGPS identified, quantified and stratified gait pathology, indicating that any of the gait measures investigated in this study can be applied as outcome measures in research and case management in lower limb amputees.

The use of the 6-min walk test as a proxy for the assessment of energy expenditure during gait in individuals with lower-limb amputation.

The objective of this study was to determine, and compare, the utility of the 6-min walk test (6 MWT) and self-selected walking speed over 15 m as proxies for the assessment of energy expenditure during gait in individuals with lower-limb amputation. Patients with unilateral, transfemoral amputation (n=6) and patients with unilateral, transtibial amputation (n=10) from community-based support groups participated in this study. Age-matched and body mass index-matched able-bodied controls (n=28) from a sample of convenience also participated. The main outcome measures were as follows: (a) distance, heart rate, oxygen consumption and oxygen cost during the 6 MWT and (b) self-selected walking speed over 15 m. Oxygen cost did not correlate significantly with self-selected walking speed over 15 m (ρ=-0.329) or average walking speed during the 6 MWT (ρ=-0.350). Significant correlations were not present between oxygen cost and the walking speed during the 6 MWT (range, ∣ρ∣: 0.210-0.531), although walking speeds at particular times of the 6 MWT demonstrated stronger correlations than others. Walking speed in the third min of walking during the 6 MWT recorded the strongest correlation with peak oxygen cost (ρ=-0.531). The 6 MWT is a submaximal measure in persons with lower-limb amputation. Self-selected walking speed over 15 m was not an appropriate proxy for the assessment of the energy cost of gait. Individuals with a lower-limb amputation require approximately 3 min of continuous walking to re-establish homoeostasis in heart rate, oxygen consumption and oxygen cost. The nonsignificant correlation between walking speeds during the 6 MWT and oxygen cost suggest that the 6 MWT can provide an indication of oxygen cost, but caution should be exercised when using it as a sole proxy for the measurement of oxygen cost in individuals with lower-limb amputation.

Patient satisfaction following lower-limb amputation: the role of gait deviation.

BACKGROUND: Patient satisfaction is an important measurement in healthcare for administrators, clinicians and patients. OBJECTIVES: This study investigated the role of gait deviation in patient satisfaction following lower-limb amputation and prosthesis prescription. STUDY DESIGN: A cross-sectional study was done. METHODS: Twenty community-based unilateral lower-limb amputees, 12 transtibial and 8 transfemoral, were recruited from support groups. Participants completed the prosthesis evaluation questionnaire (PEQ) with embedded satisfaction-related questions, the timed-up-and-go test and the six-minute walk test, and also underwent quantitative three-dimensional analysis. Kinematic deviation was summarized using the gait profile score (GPS). RESULTS: Satisfaction levels were generally high (median 80 + /100). Sociodemographic variables did not correlate significantly with any of the satisfaction measures (-0.35 ≤ r ≤ 0.54). Satisfaction correlated strongly with the PEQ scales, particularly ambulation, prosthetic utility, frustration, perceived response and social burden (r ≥ 0.70). By contrast, the relationships between satisfaction and performance-based outcome measures were not significant (-0.45 ≤ r ≤ 0.43), and the GPS did not correlate with any satisfaction measures (-0.23 ≤ r ≤ 0.15). CONCLUSIONS: In this study of high functioning amputees, gait deviation was unimportant to the amputee, while self-reported functional ability and attitudes toward the prosthesis were the strongest correlates of satisfaction following lower-limb amputation. CLINICAL RELEVANCE: For the high functioning individuals with lower-limb amputation in this study, gait deviation was not a significant correlate of patient satisfaction. RESULTS suggest that improving self-perceived functional ability and attitudes toward the prosthesis, rather than minimizing gait deviation, will improve patient satisfaction.