'A whole different ball game': the qualitative experience of older adults with a transtibial amputation and the use of a self-aligning prosthetic ankle-foot on the STEPFORWARD trial.

BACKGROUND: Older patients with lower limb amputation, categorised as having "limited community mobility", are under-researched. Understanding their experience with a new prosthetic ankle-foot is important when designing clinical trials. The aim of this qualitative study was to explore the adjustments they made after amputation and the acceptability of a self-aligning ankle-foot (SA-AF) to older adults. METHODS: Fourteen participants, who took part in the STEPFORWARD randomised controlled feasibility trial (ISRCTN15043643), were purposively recruited; nine were intervention participants and five were standard care participants. They were asked to reflect on their life prior to and consider the adjustments they made following their amputation. Participants in the intervention group were also asked about their views of the new SA-AF compared to their standard non-SA-AF. A thematic analysis was undertaken. RESULTS: Three broad themes were identified: The impact of the amputation; Role of clinical support; and Experiences of the SA-AF. The findings tell a narrative of the long-term impact that amputation has on these individuals' lives. Participants randomised to receive the SA-AF were very positive about it, reporting less pain, greater mobility and being able to do more.Participants who used the SA-AF found it an acceptable intervention. These findings suggest that a full-scale RCT is warranted.IMPLICATIONS FOR REHABILITATIONThere is a high degree of acceptability among an older patient group with a transtibial amputation to use a self-aligning ankle foot.Patients reported experiencing better mobility and more prosthetic comfort with the self-aligning ankle-foot.Key outcomes important to participants include engagement in social and daily activities and balance confidence.

Reliability of three different methods for assessing amputee residuum shape and volume: 3D scanners vs. circumferential measurements.

BACKGROUND: Objective and reliable methods are necessary to monitor and manage amputee residuum shape and volume and design prosthetic residuum-prosthesis interfaces. Portable 3D scanners are potential solutions for digitally recording the amputee residuum characteristics. OBJECTIVE: To investigate test-operator reliability when measuring lower limb residuum shape and volume using two different types of 3D laser-free scanners compared with tape measurements generally adopted in clinic. STUDY DESIGN: Ten lower limb amputees took part in this study. Residuum volume, cross sectional areas, and perimeter lengths were measured by three different operators on three different occasions using two types of 3D scanners (Artec Eva scanner and OMEGA Scanner 3D) and circumferential measurements. METHODS: Variance components, intraclass correlation coefficients and intra-rater and inter-rater reliability coefficients were calculated for all measurement conditions. RESULTS: Residuum volume outputs ranged from 569 to 3115 mL. The factor contributing mostly to the residuum volume error variance was the shape of the residuum (75.85%). Volume intraclass correlation coefficients for both intra-rater and inter-rater reliability exceeded 0.9 for all three conditions. Volume reliability coefficients ranged from 70.68 mL (Artec Eva intra-rater reliability) to 256.85 mL (circumferential measurements inter-rater reliability). Shape relative error reached the highest values for the circumferential measurements (>10% for the cross-sectional areas and >5% for the perimeters). CONCLUSIONS: The Artec Eva scanner resulted in the lowest test-operator reliability coefficients. However, both investigated scanners are a potential alternative for measuring small and macroscopic changes in residuum characteristics.

Improving Competency in Safe Patient Handling Through Online Learning Beyond the Classroom: A Longitudinal Study.

IMPORTANCE: Safe patient handling is intrinsic in health care provision, yet education in the skills required for safe patient handling is inconsistently delivered, with limited evidence that traditional face-to-face training reduces risk. OBJECTIVE: To assess the long-term effectiveness of replacing annual practical handling updates with an online training system, combined with competency assessment of skill and safety. DESIGN: Quasi-experimental longitudinal 3-yr study to track practical people handling skill development among undergraduate occupational therapy students. All participants had access to a multimedia online training system (that replaced tutor-led practical training), used in combination with annual competency evaluations to measure skills and safety in four people handling tasks. SETTING: All competency assessment took place on site in the School of Health and Society, University of Salford (Salford, United Kingdom). PARTICIPANTS: Undergraduate BSc(Hons) occupational therapy students (N = 243). Outcomes and Measures: Participants attended individual 45-min competency evaluations at three data collection points: beginning of Years 2 and 3 and end of Year 3. Data were collected by trained assessors using a competency assessment tool. RESULTS: Results demonstrate significant increases in skill level for sit-to-stand and repositioning in the chair (p < .05) and for hoisting and slide sheet maneuvers (p < .0001). Participants achieved 100% safety scores for repositioning in the chair and hoisting. CONCLUSIONS AND RELEVANCE: Students using the online system performed significantly better than students receiving traditional annual practical updates, providing an evidence base to reduce tutor-led training hours while increasing skill and safety levels using a combination of the online system and competency assessment. What This Article Adds: This approach was found to reinforce safe handling techniques and increase independence, competency, and safety of service users and caregivers working in health and social care environments while reducing time spent delivering annual people handling updates. The findings support replacement of face-to-face training updates, particularly in the current climate of social distancing.

STEPFORWARD study: a randomised controlled feasibility trial of a self-aligning prosthetic ankle-foot for older patients with vascular-related amputations.

OBJECTIVES: To determine the feasibility of conducting a full-scale randomised controlled trial (RCT) of the effectiveness and cost-effectiveness of a self-aligning prosthetic ankle-foot compared with a standard prosthetic ankle-foot. DESIGN: Multicentre parallel group feasibility RCT. SETTING: Five prosthetics centres in England recruiting from July 2018 to August 2019. PARTICIPANTS: Adults aged ≥50 years with a vascular-related or non-traumatic transtibial amputation for 1 year or longer, categorised as having 'limited community mobility' and using a non-self-aligning ankle-foot. INTERVENTION: Participants were randomised into one of two groups for 12 weeks: self-aligning prosthetic ankle-foot or existing non-self-aligning prosthetic ankle-foot. OUTCOMES: Feasibility measures: recruitment, consent and retention rates; and completeness of questionnaire and clinical assessment datasets across multiple time points. Feasibility of collecting daily activity data with wearable technology and health resource use data with a bespoke questionnaire. RESULTS: Fifty-five participants were randomised (61% of the target 90 participants): n=27 self-aligning ankle-foot group, n=28 non-self-aligning ankle-foot group. Fifty-one participants were included in the final analysis (71% of the target number of participants). The consent rate and retention at final follow-up were 86% and 93%, respectively. The average recruitment rate was 1.25 participants/site/month (95% CI 0.39 to 2.1). Completeness of questionnaires ranged from 89%-94%, and clinical assessments were 92%-95%, including the activity monitor data. The average completion rates for the EQ-5D-5L and bespoke resource use questionnaire were 93% and 63%, respectively. CONCLUSIONS: This feasibility trial recruited and retained participants who were categorised as having 'limited community mobility' following a transtibial amputation. The high retention rate of 93% indicated the trial was acceptable to participants and feasible to deliver as a full-scale RCT. The findings support a future, fully powered evaluation of the effectiveness and cost-effectiveness of a self-aligning prosthetic ankle-foot compared with a standard non-self-aligning version with some adjustments to the trial design and delivery. TRIAL REGISTRATION NUMBER: ISRCTN15043643.

Can high-functioning amputees with state-of-the-art prosthetics walk normally? A kinematic and dynamic study of 40 individuals.

BACKGROUND: Previous work has highlighted the highly functional post-rehabilitation level of military individuals who sustained traumatic amputation. Understanding how these individuals walk with their prosthesis could be key to setting a precedent for what is realistically possible in the rehabilitation of individuals with amputations. OBJECTIVE: The aim of this paper is to answer how "normal" should the gait of an individual with an amputation(s) be and can we aspire to mimic able-bodied gait with the most advanced prosthetics in highly functioning individuals? METHODS: This was a cross-sectional study comparing the gait of severely injured and highly functional UK trans-tibial (n=10), trans-femoral (n=10) and bilateral trans-femoral (n=10) military amputees after completion of their rehabilitation programme to that of able-bodied controls (n=10). Joint kinematics and kinetics of the pelvis, hip, knee and ankle were measured with 3-D gait analysis during 5min of walking on level ground at a self-selected speed. Peak angle, moment or range of motion of intact and prosthetic limbs were compared to control values. RESULTS: Joint kinematics of unilateral trans-tibial amputees was similar to that of controls. Individuals with a trans-femoral amputation walked with a more anterior tilted pelvis (P=0.006), with reduced range of pelvic obliquity (P=0.0023) and ankle plantarflexion (P<0.001) than controls. Across all amputee groups, hip joint moments and power were greater and knee and ankle joint moments were less than for controls. CONCLUSIONS: This is the first study to provide a comprehensive description of gait patterns of unilateral trans-tibial, trans-femoral and bilateral trans-femoral amputees as compared with healthy able-bodied individuals. The groups differed in joint kinematics and kinetics, but these can be expected in part because of limitations in prosthesis and socket designs. The results from this study could be considered benchmark data for healthcare professionals to compare gait patterns of other individuals with amputation who experienced similar injuries and rehabilitation services.

Self-aligning prosthetic device for older patients with vascular-related amputations: protocol for a randomised feasibility study (the STEPFORWARD study).

INTRODUCTION: The majority of older patients with a transtibial amputation are prescribed a standard (more rigid, not self-aligning) prosthesis. These are mostly suitable for level walking, and cannot adjust to different sloped surfaces. This makes walking more difficult and less energy efficient, possibly leading to longer term disuse. A Cochrane Review concluded that there was insufficient evidence to recommend any individual type of prosthetic ankle-foot mechanism. This trial will establish the feasibility of conducting a large-scale trial to assess the effectiveness and cost-effectiveness of a self-aligning prosthesis for older patients with vascular-related amputations and other health issues compared with a standard prosthesis. METHODS AND ANALYSIS: This feasibility trial is a pragmatic, parallel group, randomised controlled trial (RCT) comparing standard treatment with a more rigid prosthesis versus a self-aligning prosthesis. The target sample size is 90 patients, who are aged 50 years and over, and have a transtibial amputation, where amputation aetiology is mostly vascular-related or non-traumatic. Feasibility will be measured by consent and retention rates, a plausible future sample size over a 24-month recruitment period and completeness of outcome measures. Qualitative interviews will be carried out with trial participants to explore issues around study processes and acceptability of the intervention. Focus groups with staff at prosthetics centres will explore barriers to successful delivery of the trial. Findings from the qualitative work will be integrated with the feasibility trial outcomes in order to inform the design of a full-scale RCT. ETHICS AND DISSEMINATION: Ethical approval was granted by Yorkshire and the Humber-Leeds West Research Ethics Committee on 4 May 2018. The findings will be disseminated via peer-reviewed research publications, articles in relevant newsletters, presentations at relevant conferences and the patient advisory group. TRIAL REGISTRATION NUMBER: ISRCTN15043643.

Performance of Optimized Prosthetic Ankle Designs That Are Based on a Hydraulic Variable Displacement Actuator (VDA).

Current energy storage and return prosthetic feet only marginally reduce the cost of amputee locomotion compared with basic solid ankle cushioned heel feet, possibly due to their lack of push-off at the end of stance. To the best of our knowledge, a prosthetic ankle that utilizes a hydraulic variable displacement actuator (VDA) to improve push-off performance has not previously been proposed. Therefore, here we report a design optimization and simulation feasibility study for a VDA-based prosthetic ankle. The proposed device stores the eccentric ankle work done from heel strike to maximum dorsiflexion in a hydraulic accumulator and then returns the stored energy to power push-off. Optimization was used to establish the best spring characteristic and gear ratio between ankle and VDA. The corresponding simulations show that, in level walking, normal push-off is achieved and, per gait cycle, the energy stored in the accumulator increases by 22% of the requirements for normal push-off. Although the results are promising, there are many unanswered questions and, for this approach to be a success, a new miniature, low-losses, and lightweight VDA would be required that is half the size of the smallest commercially available device.

Validity and reliability of a novel 3D scanner for assessment of the shape and volume of amputees' residual limb models.

BACKGROUND: Objective assessment methods to monitor residual limb volume following lower-limb amputation are required to enhance practitioner-led prosthetic fitting. Computer aided systems, including 3D scanners, present numerous advantages and the recent Artec Eva scanner, based on laser free technology, could potentially be an effective solution for monitoring residual limb volumes. PURPOSE: The aim of this study was to assess the validity and reliability of the Artec Eva scanner (practical measurement) against a high precision laser 3D scanner (criterion measurement) for the determination of residual limb model shape and volume. METHODS: Three observers completed three repeat assessments of ten residual limb models, using both the scanners. Validity of the Artec Eva scanner was assessed (mean percentage error <2%) and Bland-Altman statistics were adopted to assess the agreement between the two scanners. Intra and inter-rater reliability (repeatability coefficient <5%) of the Artec Eva scanner was calculated for measuring indices of residual limb model volume and shape (i.e. residual limb cross sectional areas and perimeters). RESULTS: Residual limb model volumes ranged from 885 to 4399 ml. Mean percentage error of the Artec Eva scanner (validity) was 1.4% of the criterion volumes. Correlation coefficients between the Artec Eva and the Romer determined variables were higher than 0.9. Volume intra-rater and inter-rater reliability coefficients were 0.5% and 0.7%, respectively. Shape percentage maximal error was 2% at the distal end of the residual limb, with intra-rater reliability coefficients presenting the lowest errors (0.2%), both for cross sectional areas and perimeters of the residual limb models. CONCLUSION: The Artec Eva scanner is a valid and reliable method for assessing residual limb model shapes and volumes. While the method needs to be tested on human residual limbs and the results compared with the current system used in clinical practice, it has the potential to quantify shape and volume fluctuations with greater resolution.

Temporal Spatial and Metabolic Measures of Walking in Highly Functional Individuals With Lower Limb Amputations.

OBJECTIVE: To record the temporal spatial parameters and metabolic energy expenditure during walking of individuals with amputation, walking with advanced prostheses, and after completion of comprehensive rehabilitation compared with able-bodied persons. DESIGN: Cross-sectional. SETTING: Multidisciplinary comprehensive rehabilitation center. PARTICIPANTS: Severely injured UK military personnel with amputation and subsequent completion of their rehabilitation program (n=30; unilateral transtibial: n=10, unilateral transfemoral: n=10, and bilateral transfemoral: n=10) were compared with able-bodied persons (n=10) with similar age, height, and mass (P>.537). Total number of participants (N = 40). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Temporal spatial and metabolic energy expenditure data were captured during walking on level ground at a self-selected speed. RESULTS: The individuals with amputation were all men, with a mean age of 29±4 years and a mean New Injury Severity Score of 31±16. Walking speed, stride length, step length, and cadence of individuals with a unilateral transtibial or transfemoral amputation were comparable with able-bodied persons, and only individuals with a bilateral transfemoral amputation had a significantly slower walking speed (1.12m/s, P=.025) and reduced cadence (96 steps per minute, P=.026). Oxygen cost for individuals with a unilateral transtibial amputation (0.15mL/kg/m) was the same as for able-bodied persons (0.15mL/kg/m) and significantly increased by 20% (0.18mL/kg/m, P=.023) for unilateral transfemoral amputation and by 60% (0.24mL/kg/m, P<.001) for bilateral transfemoral individuals with amputation. CONCLUSIONS: The scientific literature reports a wide range of gait and metabolic energy expenditure across individuals with amputation. The results of this study indicate that individuals with amputation have a gait pattern which is highly functional and efficient. This is comparable with a small number of studies reporting similar outcomes for individuals with a unilateral transtibial amputation, but the results from this study are better than those on individuals with transfemoral amputations reported elsewhere, despite comparison with populations wearing similar prosthetic componentry. Those studies that do report similar outcomes have included individuals who have been provided with a comprehensive rehabilitation program. This suggests that such a program may be as important as, or even more important than, prosthetic component selection in improving metabolic energy expenditure. The data are made available as a benchmark for what is achievable in the rehabilitation of some individuals with amputations, but agreeably may not be possible for all amputees to achieve.

The effects of prosthetic ankle stiffness on stability of gait in people with transtibial amputation.

The ability to control balance during walking is a critical precondition for minimizing fall risk, but this ability is compromised in persons with lower-limb absence because of reduced sensory feedback mechanisms and inability to actively modulate prosthesis mechanical function. Consequently, these individuals are at increased fall risk compared with nondisabled individuals. A number of gait parameters, including symmetry and temporal variability in step/stride characteristics, have been used as estimates of gait stability and fall risk. This study investigated the effect of prosthetic ankle rotational stiffness on gait parameters related to walking stability of transtibial prosthesis users. Five men walked with an experimental prosthesis that allowed for independent modulation of plantar flexion and dorsiflexion stiffness. Two levels of plantar flexion and dorsiflexion stiffness were tested during level, uphill, and downhill walking. The results demonstrate that low plantar flexion stiffness reduced time to foot-flat, and this was associated with increased perceived stability, while low dorsiflexion stiffness demonstrated trends in temporal-spatial parameters that are associated with improved gait stability (reduced variability and asymmetry). Prosthesis design and prescription for low rotational stiffness may enhance gait safety for transtibial prosthesis users at risk of unsteadiness and falls.

Restricting ankle motion via orthotic bracing reduces toe clearance when walking over obstacles.

BACKGROUND: When trans-tibial amputees cross obstacles leading with their prosthesis, foot clearance is achieved using compensatory swing-phase kinematics. Such compensation would suggest able-bodied individuals normally use swing-phase ankle dorsiflexion to attain adequate obstacle clearance; however, direct evidence of such contribution is equivocal. This study determined the contribution of sagittal plane ankle motion in achieving lead-limb clearance during obstacle negotiation. METHODS: Twelve male able-bodied individuals (ages 18-30) completed obstacle crossing trials while walking on a flat surface. Lead-limb (right) ankle motion was manipulated using a knee-ankle-foot orthosis. Trials were completed with the ankle restricted at a neutral angle or unrestricted (allowing ∼±15° plantar/dorsiflexion). FINDINGS: Restricted ankle motion caused significant increase in trail-limb foot placement distance before the obstacle (p=0.005); significant decrease in vertical toe clearance (p<0.003), vertical heel clearance (p=0.045), and lead-limb foot placement distance after the obstacle (p=0.045); but no significant changes in knee angle at instant of crossing or in average walking speed. INTERPRETATION: The shifts in foot placements altered the part of swing that the lead-limb was in when the foot crossed the obstacle, which led to a decrease in clearance. These adaptations may have been due to being unable to dorsiflex the ankle to 'lift' the toes in mid-swing or to plantarflex the ankle during initial contact following crossing, which changed how the lead-limb was to be loaded. These findings suggest individuals using ankle bracing or those with ankle arthrodesis, will have reduced gait safety when negotiating obstacles.

A systematic procedure to optimise dose and image quality for the measurement of inter-vertebral angles from lateral spinal projections using Cobb and superimposition methods.

BACKGROUND: Patients with vertebral column deformations are exposed to high risks associated with ionising radiation exposure. Risks are further increased due to the serial X-ray images that are needed to measure and asses their spinal deformation using Cobb or superimposition methods. Therefore, optimising such X-ray practice, via reducing dose whilst maintaining image quality, is a necessity. OBJECTIVES: With a specific focus on lateral thoraco-lumbar images for Cobb and superimposition measurements, this paper outlines a systematic procedure to the optimisation of X-ray practice. METHODS: Optimisation was conducted based on suitable image quality from minimal dose. Image quality was appraised using a visual-analogue-rating-scale, and Monte-Carlo modelling was used for dose estimation. The optimised X-ray practice was identified by imaging healthy normal-weight male adult living human volunteers. RESULTS: The optimised practice consisted of: anode towards the head, broad focus, no OID or grid, 80 kVp, 32 mAs and 130 cm SID. CONCLUSION: Images of suitable quality for laterally assessing spinal conditions using Cobb or superimposition measurements were produced from an effective dose of 0.05 mSv, which is 83% less than the average effective dose used in the UK for lateral thoracic/lumbar exposures. This optimisation procedure can be adopted and use for optimisation of other radiographic techniques.

Validation of the activPAL activity monitor in children with hemiplegic gait patterns resultant from cerebral palsy.

BACKGROUND: Current investigation of treatment outcomes by clinicians is currently hampered by a lack of clinically viable tools. The use of activity monitors specifically validated for a population could help resolve this situation. OBJECTIVES: The purpose of the study was to validate an activity monitor for monitoring children with cerebral palsy. The study was designed to validate the duration of time spent sitting, standing and walking and the number of steps taken when being measured by the activPAL activity monitor. STUDY DESIGN: A validation study was undertaken. METHODS: Observations of participants were carried out while completing a specifically designed activity course using video footage, which were then compared to the output from the activity monitor. RESULTS: The activity monitor was found to be valid for the time spent standing and walking, the number of steps taken and the number of transitions. CONCLUSIONS: The results demonstrated that the monitor may prove useful to clinicians as a measurement outcome device for children with hemiplegic gait patterns resultant from cerebral palsy. However, the sensitivity of the device is variable, and further investigations are necessary to confirm it would also be able to detect minor changes after interventions. CLINICAL RELEVANCE: The monitor may provide clinicians with a simplistic tool that is easily utilised, to enable audit exercises of current and future treatments.

The effects of prosthetic ankle stiffness on ankle and knee kinematics, prosthetic limb loading, and net metabolic cost of trans-tibial amputee gait.

BACKGROUND: Previous studies of commercially-available trans-tibial prosthetic components have been unable to provide clear insight into the relationships between prosthetic mechanical properties and user performance (i.e., gait quality and energy expenditure), the understanding of which is key to improving prosthesis design and prescription. Many of these studies have been limited by not characterising the mechanical properties of the tested prostheses and/or only considered level walking at self-selected speeds. The aim of this study was to conduct a systematic investigation of the effects of ankle rotational stiffness on trans-tibial amputee gait during various walking conditions reflective of those encountered during daily ambulation. METHODS: Ankle and knee kinematics, prosthetic limb normal ground reaction forces, and net metabolic cost were measured in five traumatic unilateral trans-tibial amputees during treadmill walking on the level, a 5% incline and a 5% decline whilst using an experimental articulated prosthetic foot with four different rotational stiffness setups and without changes in alignment between conditions. FINDINGS: Overall, lower dorsiflexion stiffness resulted in greater prosthetic side dorsiflexion motion and sound side knee flexion, reduced normal ground reaction force during the loading phase of prosthetic stance and reduced net metabolic cost. INTERPRETATION: Few differences were observed with changes in plantarflexion stiffness, most likely due to the foot achieving early foot flat. Low dorsiflexion stiffness generally improved gait performance seemingly due to easier tibial progression during stance. However, observed differences were small, suggesting that a wider range of walking and stiffness conditions would be useful to fully explore these effects in future studies.

The effects of transverse rotation angle on compression and effective lever arm of prosthetic feet during simulated stance.

BACKGROUND AND AIM: Unlike sagittal plane prosthesis alignment, few studies have observed the effects of transverse plane alignment on gait and prosthesis behaviour. Changes in transverse plane rotation angle will rotate the points of loading on the prosthesis during stance and may alter its mechanical behaviour. This study observed the effects of increasing the external transverse plane rotation angle, or toe-out, on foot compression and effective lever arm of three commonly prescribed prosthetic feet. TECHNIQUE: The roll-over shape of a SACH, Flex and single-axis foot was measured at four external rotation angle conditions (0°, 5°, 7° and 12° relative to neutral). Differences in foot compression between conditions were measured as average distance between roll-over shapes. DISCUSSION: Increasing the transverse plane rotation angle did not affect foot compression. However, it did affect the effective lever arm, which was maximized with the 5° condition, although differences between conditions were small. CLINICAL RELEVANCE: Increasing the transverse plane rotation angle of prosthetic feet by up to 12° beyond neutral has minimal effects on their mechanical behaviour in the plane of walking progression during weight-bearing.

Stance phase mechanical characterization of transtibial prostheses distal to the socket: a review.

Achieving the required functionality of a transtibial prosthesis during the stance phase of gait (e.g., shock absorption, close to normal roll-over characteristics, and smooth transition into swing) depends on the Amputee Independent Prosthesis Properties (AIPPs), defined here as the mechanical properties of the prosthesis that directly influence the performance of the amputee. Accordingly, if research studies are to advance the design of prostheses to achieve improved user performance, AIPPs must be a primary consideration. However, the majority of reported studies can be categorized as either human performance testing of commercial prosthetic components or AIPP characterization; only in a few notable cases have studies combined these two approaches. Moreover, very little consistency exists in the current methods used for AIPP characterization, thus making comparisons between the results of such studies very difficult. This article introduces a framework for studying prosthesis design, which includes AIPP characterization, human performance and/or gait simulation studies, and detailed design. This framework provides a structure for reviewing previous approaches to AIPP characterization, discussing both their merits and shortcomings and their use in previous experimental and simulation studies. For the purposes of this review, stance phase AIPP models have been categorized as either lumped parameter or roll-over shape based.

Amputee Independent Prosthesis Properties--a new model for description and measurement.

A model is presented for describing the Amputee Independent Prosthesis Properties (AIPP) of complete assemblies of trans-tibial prosthetic components distal to the socket. This new AIPP model includes features of both lumped parameter and roll-over models and describes prosthesis properties that are of importance in stance phase, including prosthetic foot geometry, normal stiffness, shear stiffness, and damping (energy dissipation). Methods are described for measuring the parameters of the AIPP model using a custom test-rig, commercial load-cell, and a motion capture system. Example data are presented for five pylon angles reflecting the shank angles seen in normal gait. Through the inclusion of measured AIPP in future in-vivo studies comparing different prostheses more generic information, as opposed to product specific claims, will become more widely available to inform future designs, prescription, and alignment procedures.

Transverse rotation and longitudinal translation during prosthetic gait--a literature review.

Improved technology allows for more accurate gait analysis to increase awareness of nonoptimized prosthetic gait patterns and for the manufacture of sophisticated prosthetic components to improve nonoptimized gait patterns. However, prescriptions are often based on intuition rather than rigorous research findings for evidence-based practice. The number of studies found in the literature that are based on prosthetic research regarding transverse rotation and longitudinal translation is small when compared to topics regarding other types of movements. Some design criteria for prosthetic components described in those studies that permit transverse rotation and longitudinal translation can be found in current designs. However, little research has been conducted to establish their effectiveness on the gait parameters and residual limb. This literature review is an investigation into these motions between the socket and the prosthetic foot, with particular reference to gait characteristics and prosthetic design criteria.