Femur Abduction Associated with Transfemoral Amputation Alters the Profile of Lumbopelvic Mechanical Loads During Generalized End-Limb Loading

Background: A stance-yielding mechanism for prosthetic knees may reduce lower limb loading during specific activities, but quantitative data are insufficient. Objectives: To clarify the biomechanical effect of a non-microprocessor-controlled stance-yielding mechanism on ramp descent for individuals with unilateral transfemoral amputation. Study design: Intra-subject intervention study. Methods: Seven individuals with unilateral transfemoral amputation underwent three-dimensional motion analysis of ramp descent with and without activating a stance-yielding mechanism. Regarding early-stance internal joint moment and ground reaction force, whole-group and subgroup analyses stratified by stance prosthetic knee flexion were performed to verify differences in prosthetic side and contralateral limb loading between conditions. Results: Whole-group analysis revealed significant reduction in early-stance prosthetic knee extension moment with stance-yielding mechanism activation. Changes in prosthetic side hip extension moment and contralateral limb loading were inconsistent between conditions. Subjects with prosthetic stance knee flexion walked slower with a smaller stride and greater increase in aft ground reaction force and ankle dorsiflexion moment when stance-yielding was activated. Conclusion: Stance-yielding mechanism has a biomechanical potential to decrease excessive knee hyperextension. However, prosthetic side stance knee flexion induced by the stance-yielding mechanism might not necessarily reduce the mechanical load on residual hip or contralateral lower limb joints. Clinical relevance This study showed individual variability in the possibility of reducing the load on the remaining lower limb when using a non-microprocessor-controlled stance-yielding knee. This suggests that individualized prosthetic management and monitoring the activities of individuals wearing a stance-yielding prosthetic knee are crucial to maximize the benefits of stance-yielding prosthetic knees.

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The influence of continuous local wound infusion on postoperative pain in patients undergoing transfemoral amputation

VASA ◽

10.1024/0301-1526/a000457 ◽

2015 ◽

Vol 44 (5) ◽

pp. 381-386 ◽

Cited By ~ 1

Author(s):

Christian Uhl ◽

Thomas Betz ◽

Andrea Rupp ◽

Markus Steinbauer ◽

Ingolf Töpel

Keyword(s):

Pain Management ◽

Pilot Study ◽

Local Anaesthetic ◽

Phantom Pain ◽

Transfemoral Amputation ◽

Postoperative Wound ◽

Stump Pain ◽

Management Protocol ◽

Group 2 ◽

Group 1

Abstract. Summary: Background: This pilot study was set up to examine the effects of a continuous postoperative wound infusion system with a local anaesthetic on perioperative pain and the consumption of analgesics. Patients and methods: We included 42 patients in this prospective observational pilot study. Patients were divided into two groups. One group was treated in accordance with the WHO standard pain management protocol and in addition to that received a continuous local wound infusion treatment (Group 1). Group 2 was treated with analgesics in accordance with the WHO standard pain management protocol, exclusively. Results: The study demonstrated a significantly reduced postoperative VAS score for stump pain in Group 1 for the first 5 days. Furthermore, the intake of opiates was significantly reduced in Group 1 (day 1, Group 1: 42.1 vs. Group 2: 73.5, p = 0.010; day 2, Group 1: 27.7 vs. Group 2: 52.5, p = 0.012; day 3, Group 1: 23.9 vs. Group 2: 53.5, p = 0.002; day 4, Group 1: 15.7 vs. Group 2: 48.3, p = 0.003; day 5, Group 1 13.3 vs. Group 2: 49.9, p = 0.001). There were no significant differences between the two groups, neither in phantom pain intensity at discharge nor postoperative complications and death. Conclusions: Continuous postoperative wound infusion with a local anaesthetic in combination with a standard pain management protocol can reduce both stump pain and opiate intake in patients who have undergone transfemoral amputation. Phantom pain was not significantly affected.

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Analysis and design of thermo-mechanical interfaces

Bulletin of the Polish Academy of Sciences Technical Sciences ◽

10.2478/v10175-012-0027-4 ◽

2012 ◽

Vol 60 (2) ◽

pp. 205-213

Author(s):

K. Dems ◽

Z. Mróz

Keyword(s):

Optimality Conditions ◽

Mechanical Loading ◽

Material Properties ◽

Structural Response ◽

External Boundary ◽

Mechanical Loads ◽

Internal Interface ◽

Analysis And Design ◽

First Order ◽

Mechanical Nature

Abstract. An elastic structure subjected to thermal and mechanical loading with prescribed external boundary and varying internal interface is considered. The different thermal and mechanical nature of this interface is discussed, since the interface form and its properties affect strongly the structural response. The first-order sensitivities of an arbitrary thermal and mechanical behavioral functional with respect to shape and material properties of the interface are derived using the direct or adjoint approaches. Next the relevant optimality conditions are formulated. Some examples illustrate the applicability of proposed approach to control the structural response due to applied thermal and mechanical loads.

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Transportation loads. Measurement and evaluation of dynamic mechanical loads

10.3403/30143788 ◽

2008 ◽

Keyword(s):

Mechanical Loads ◽

Dynamic Mechanical ◽

Measurement And Evaluation

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Transportation loads. Measurement and evaluation of dynamic mechanical loads

10.3403/30143780u ◽

2015 ◽

Keyword(s):

Mechanical Loads ◽

Dynamic Mechanical ◽

Measurement And Evaluation

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Investigation of Fundamental Processes and Crystal-Level Defect Structures in Metal-Loaded High-Explosive Materials under Dynamic Thermo-Mechanical Loads and their Relationships to Impact Survivability of Munitions (Thrust 4, Topic J)

10.21236/ada606813 ◽

2014 ◽

Author(s):

Donald L. Thompson ◽

Thomas D. Sewell ◽

R. H. Bouma ◽

A. E. van der Heijden

Keyword(s):

High Explosive ◽

Defect Structures ◽

Mechanical Loads ◽

Explosive Materials

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Microstructural Analysis of Fractured Orthopedic Implants

Materials ◽

10.3390/ma14092209 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2209

Author(s):

Mateusz Kopec ◽

Adam Brodecki ◽

Grzegorz Szczęsny ◽

Zbigniew L. Kowalewski

Keyword(s):

Physical Activity ◽

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Fracture Behavior ◽

Locking Plate ◽

Microstructural Analysis ◽

Pure Titanium ◽

Orthopedic Implants ◽

Mechanical Loads ◽

Scanning Electron

In this paper, fracture behavior of four types of implants with different geometries (pure titanium locking plate, pure titanium femoral implant, Ti-6Al-4V titanium alloy pelvic implant, X2CrNiMo18 14-3 steel femoral implant) was studied in detail. Each implant fractured in the human body. The scanning electron microscopy (SEM) was used to determine the potential cause of implants fracture. It was found that the implants fracture mainly occurred in consequence of mechanical overloads resulting from repetitive, prohibited excessive limb loads or singular, un-intendent, secondary injures. Among many possible loading types, the implants were subjected to an excessive fatigue loads with additional interactions caused by screws that were mounted in their threaded holes. The results of this work enable to conclude that the design of orthopedic implants is not fully sufficient to transduce mechanical loads acting over them due to an increasing weight of treated patients and much higher their physical activity.

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An Investigation of the Physical and Electrical Properties of Knitted Electrodes When Subjected to Multi-Axial Compression and Abrasion

Proceedings ◽

10.3390/proceedings2021068002 ◽

2021 ◽

Vol 68 (1) ◽

pp. 2

Author(s):

Arash M. Shahidi ◽

Theodore Hughes-Riley ◽

Carlos Oliveira ◽

Tilak Dias

Keyword(s):

Heart Rate ◽

Electrical Properties ◽

Applied Load ◽

Pressure Sensors ◽

Electrical Performance ◽

Electronic Textiles ◽

Heart Rate Monitors ◽

Mechanical Loads ◽

And Performance ◽

Over Time

Knitted electrodes are a key component to many electronic textiles including sensing devices, such as pressure sensors and heart rate monitors; therefore, it is essential to assess the electrical performance of these knitted electrodes under different mechanical loads to understand their performance during use. The electrical properties of the electrodes could change while deforming, due to an applied load, which could occur in the uniaxial direction (while stretched) or multiaxial direction (while compressed). The properties and performance of the electrodes could also change over time when rubbed against another surface due to the frictional force and generated heat. This work investigates the behavior of a knitted electrode under different loading conditions and after multiple abrasion cycles.

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Thermal Effects on Surface and Subsurface Modifications in Laser-Combined Deep Rolling

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp5020055 ◽

2021 ◽

Vol 5 (2) ◽

pp. 55

Author(s):

Robert Zmich ◽

Daniel Meyer

Keyword(s):

Surface Layer ◽

Residual Stresses ◽

Thermal Loads ◽

Deep Rolling ◽

Mechanical Loads ◽

Thermomechanical Process ◽

Compressive Stresses ◽

New Process ◽

Negative Effect ◽

Compressive Residual Stresses

Knowledge of the relationships between thermomechanical process loads and the resulting modifications in the surface layer enables targeted adjustments of the required surface integrity independent of the manufacturing process. In various processes with thermomechanical impact, thermal and mechanical loads act simultaneously and affect each other. Thus, the effects on the modifications are interdependent. To gain a better understanding of the interactions of the two loads, it is necessary to vary thermal and mechanical loads independently. A new process of laser-combined deep rolling can fulfil exactly this requirement. The presented findings demonstrate that thermal loads can support the generation of residual compressive stresses to a certain extent. If the thermal loads are increased further, this has a negative effect on the surface layer and the residual stresses are shifted in the direction of tension. The results show the optimum range of thermal loads to further increase the compressive residual stresses in the surface layer and allow to gain a better understanding of the interactions between thermal and mechanical loads.

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