1,720,962 research outputs found
IMPACT OF AMPUTATION LEVEL AND VAULTING ON LOADING PARAMETERS DURING LEVEL GROUND WALKING
No full textBACKGROUND: Previous studies show that during level walking, the load on the contralateral side increases with more proximal amputation levels. Furthermore, a typical compensation mechanism, vaulting on the contralateral side, may also influence the load. However, no study has compared the load applied to the contralateral side across more than two different amputation levels. OBJECTIVE: The objectives of this study were to analyze the biomechanical impact of different lower limb amputation levels and vaulting on the load applied to the locomotor system. METHODOLOGY: Gait data from 82 individuals with different amputation levels (44 transtibial (TT), 30 transfemoral (TF), and 8 hip disarticulation (HD)) were retrospectively analyzed in this study. Peak knee adduction, flexion and extension moments, vertical ground reaction force peaks, and force rates were statistically analyzed between different amputation levels and between two groups “TF with vaulting” and “TF without vaulting”. FINDINGS: As the level of amputation increases, walking speed decreases and asymmetry of stance duration increases. TF individuals with vaulting tend to walk faster than those without vaulting. The first peak of vertical ground reaction forces, the peak knee adduction and extension moments increase, and the peak knee flexion moments decrease with higher amputation level. The higher the amputation level, the curve of the vertical ground reaction force becomes significantly steeper during the first 5% of the gait cycle (GC). The first peak of ground reaction forces, the knee flexion, extension and adduction moments tend to be higher in TF individuals with vaulting. CONCLUSION: In summary, a higher lower limb amputation level can increase loading on the contralateral limb and contribute to a higher incidence of vaulting during gait. The effect of vaulting as a compensation pattern leads to an additional increase in contralateral limb loading. Layman's Abstract Gait characteristics in people using lower limb prostheses deviate from normal gait patterns in individuals without amputation. Furthermore, some people with amputation rise onto the toes of their intact side (a movement known as vaulting) as a compensatory mechanism during walking, which helps them clear the ground on the prosthetic side. In people with lower limb amputation, the load applied to the intact side during level walking is higher compared to able-bodied individuals, and it increases as the level of amputation progresses from below the knee to hip disarticulation. No previous study has compared the load applied to the intact side across more than two different amputation levels. The aims of the present study were to analyze the influence of the amputation level and of vaulting on the load applied to the lower limb. Therefore, we analyzed previously collected gait data from 82 individuals with amputation (44 transtibial, 30 transfemoral, and 8 with hip disarticulation). As the level of amputation increases, walking speed decreases and individuals tend to spend more time on the intact side than the prosthetic side during each gait cycle. Individuals with transfemoral amputation who use vaulting as a compensatory movement tend to walk faster than those who do not use this strategy and experience higher forces on the intact limb. As the level of amputation increases, most of the forces applied to the body during level walking also increase. Furthermore, vaulting is more common in individuals with higher amputation levels. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/44416/33698 How To Cite: Pröbsting E, Schmalz T, Bellmann M. Impact of amputation level and vaulting on loading parameters during level ground walking. Canadian Prosthetics & Orthotics Journal. 2025; Volume 8, Issue 1, No. 2. Https://doi.org/10.33137/cpoj.v8i1.44416 Corresponding Author: Eva Pröbsting, Dipl.-Ing (FH)Affiliation: Clinical Research and Services, Research Biomechanics, Ottobock SE & Co. KGaA, Göttingen, Germany.E-Mail: [email protected] ID: https://orcid.org/0000-0002-6349-299
Comparative Biomechanical Analysis of Current Microprocessor-Controlled Prosthetic Knee Joints
No full textBellmann M, Schmalz T, Blumentritt S. Comparative biomechanical analysis of current microprocessor-controlled prosthetic knee joints. Arch Phys Med Rehabil 2010; 91:644-52. Objective: To investigate and identify functional differences of 4 microprocessor-controlled prosthetic knee joints (C-Leg, Hybrid Knee [also called Energy Knee], Rheo Knee, Adaptive 2). Design: Tested situations were walking on level ground, on stairs and ramps; additionally, the fall prevention potentials for each design were examined. The measuring technology used included an optoelectronic camera system combined with 2 forceplates as well as a mobile spiroergometric system. Setting: The study was conducted in a gait laboratory. Participants: Subjects with unilateral transfemoral amputations (N=9; mobility grade, 3-4; age, 22-49y) were tested. Interventions: Participants were fitted and tested with 4 different microprocessor-controlled knee joints. Main Outcome Measures: Static prosthetic alignment, time distance parameters, kinematic and kinetic data and metabolic energy consumption. Results: Compared with the Hybrid Knee and the Adaptive 2, the C-Leg offers clear advantages in the provision of adequate swing phase flexion resistances and terminal extension damping during level walking at various speeds, especially at higher walking speeds. The Rheo Knee provides sufficient terminal extension; however, swing phase flexion resistances seem to be too low. The values for metabolic energy consumption show only slight differences during level walking. The joint resistances generated for descending stairs and ramps relieve the contralateral side to varying degrees. When walking on stairs, safety-relevant technical differences between the investigated joint types can be observed. Designs with adequate internal resistances offer stability advantages when the foot is positioned on the step. Stumble recovery tests reveal that the different knee joint designs vary in their effectiveness in preventing the patient from falling. Conclusions: The patient benefits provided by the investigated electronic prosthetic knee joints differ considerably. The C-Leg appears to offer the amputee greater functional and safety-related advantages than the other tested knee joints. Reduced loading of the contralateral side has been demonstrated during ramp and stair descent. Metabolic energy consumption does not vary significantly between the tested knees. Hence, this parameter seems not to be a suitable criterion for assessing microprocessor-controlled knee components
Influencing factors on swing phase ground clearance in transfemoral prostheses – A biomechanical study
No full textImmediate Effects of a New Microprocessor-Controlled Prosthetic Knee Joint: A Comparative Biomechanicall Evaluation
No full textBellmann M, Schmalz T, Ludwigs E, Blumentritt S. Immediate effects of a new microprocessor-controlled prosthetic knee joint: a comparative biomechanical evaluation. Arch Phys Med Rehabil 2012;93:541-9. Objective: To investigate the immediate biomechanical effects after transition to a new microprocessor-controlled prosthetic knee joint. Design: Intervention cross-over study with repeated measures. Only prosthetic knee joints were changed. Setting: Motion analysis laboratory. Participants: Men (N=11; mean age +/- SD, 36.7 +/- 10.2y; Medicare functional classification level, 3-4) with unilateral transfemoral amputation. Interventions: Two microprocessor-controlled prosthetic knee joints: C-Leg and a new prosthetic knee joint, Genium. Main Outcome Measures: Static prosthetic alignment, time-distance parameters, kinematic and kinetic parameters, and center of pressure. Results: After a half-day training and an additional half-day accommodation, improved biomechanical outcomes were demonstrated by the Genium: lower ground reaction forces at weight acceptance during level walking at various velocities, increased swing phase flexion angles during walking on a ramp, and level walking with small steps. Maximum knee flexion angle during swing phase at various velocities was nearly equal for Genium. Step-over-step stair ascent with the Genium knee was more physiologic as demonstrated by a more equal load distribution between the prosthetic and contralateral sides and a more natural gait pattern. When descending stairs and ramps, knee flexion moments with the Genium tended to increase. During quiet stance on a decline, subjects using Genium accepted higher loading of the prosthetic side knee joint, thus reducing same side hip joint loading as well as postural sway. Conclusions: In comparision to the C-Leg, the Genium demonstrated immediate biomechanical advantages during various daily ambulatory activities, which may lead to an increase in range and diversity of activity of people with above-knee amputations. Results showed that use of the Genium facilitated more natural gait biomechanics and load distribution throughout the affected and sound musculoskeletal structure. This was observed during quiet stance on a decline, walking on level ground, and walking up and down ramps and stairs
How does ankle power on the prosthetic side influence loading parameters on the sound side during level walking of persons with transfemoral amputation?
No full textIncreased ankle power on the prosthetic side seems to decrease biomechanical loading parameters on the sound side. This assumption is based on biomechanical comparisons of different foot constructions. However, such study designs could not show whether the amount of ankle power solely influences the sound side. OBJECTIVE: To analyze the influence of divergent ankle power, resulting from different foot constructions and from different ankle power settings, on the sound side loading parameters. STUDY DESIGN: Interventional cross sectional study. METHODS: Level walking of transfemoral amputees with a microprocessor knee joint and Solid Ankle Cushioned Heel (SACH), energy storing and returning (ESR) and powered foot (PF) was analyzed. The PF was adapted in three configurations: without power (np), low power (lp), and optimal power (op). An optoelectronic camera system with 12 cameras and two force plates were used. RESULTS: The ankle power on the prosthetic side shows significant differences about foot types and different settings of the PF. The knee adduction moment, the knee flexion moment, and the vertical ground reaction forces on the sound side were significantly reduced with PF_op and ESR in comparison to SACH. When analyzing these parameters for the different PF configurations, only some show significant results at normal velocity. CONCLUSIONS: The additional positive mechanical work for an active push off in the PF tends to have a relieving effect. The biomechanical sound side loading parameters are reduced with PF_op in comparison to SACH and ESR, resulting in a relief of the sound side of lower limb amputees
Effects of sagittal plane axis shifts in hinged ankle-foot orthoses on gait mechanics and shaft-to-leg relative motion
No full textLimitations of standard gait models for the precise and accurate evaluation of prosthetic knee joints regarding their functional quality, reliability, reproducibility and safety
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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