The Impact of Transfemoral Socket Adduction on Pelvic and Trunk Stabilization During Level Walking – a Biomechanical Study

2021 ◽  
Author(s):  
Thomas Maximilian Köhler
Keyword(s):  
Biomechanical Study ◽  
Level Walking ◽  
The Impact ◽  
Trunk Stabilization

scholarly journals Mapping of the Inferior Glenohumeral Ligament for Suture Pullout Strength: A Biomechanical Analysis

2021 ◽  
Vol 9 (1) ◽  
pp. 232596712096964
Author(s):  
Sumit Raniga ◽  
Joseph Cadman ◽  
Danè Dabirrahmani ◽  
David Bui ◽  
Richard Appleyard ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Biomechanical Study ◽  
Labral Repair ◽  
Pullout Strength ◽  
Recurrent Instability ◽  
Glenohumeral Ligament ◽  
Time Zero ◽  
Capsular Plication ◽  
Inferior Glenohumeral Ligament ◽  
The Impact

Background: Suture pullout during rehabilitation may result in loss of tension in the inferior glenohumeral ligament (IGHL) and contribute to recurrent instability after capsular plication, performed with or without labral repair. To date, the suture pullout strength in the IGHL is not well-documented. This may contribute to recurrent instability. Purpose/Hypothesis: A cadaveric biomechanical study was designed to investigate the suture pullout strength of sutures in the IGHL. We hypothesized that there would be no significant variability of suture pullout strength between specimens and zones. Additionally, we sought to determine the impact of early mobilization on sutures in the IGHL at time zero. We hypothesized that capsular plication sutures would fail under low load. Study Design: Descriptive laboratory study. Methods: Seven fresh-frozen cadaveric shoulders were dissected to isolate the IGHL complex, which was then divided into 18 zones. Sutures in these zones were attached to a linear actuator, and the resistance to suture pullout was recorded. A suture pullout strength map of the IGHL was constructed. These loads were used to calculate the load applied at the hand that would initiate suture pullout in the IGHL. Results: Mean suture pullout strength for all specimens was 61.6 ± 26.1 N. The maximum load found to cause suture pullout through tissue was found to be low, regardless of zone of the IGHL. Calculations suggest that an external rotation force applied to the hand of only 9.6 N may be sufficient to tear capsular sutures at time zero. Conclusion: This study did not provide clear evidence of desirable locations for fixation in the IGHL. However, given the low magnitude of failure loads, the results suggest the timetable for initiation of range-of-motion exercises should be reconsidered to prevent suture pullout through the IGHL. Clinical Relevance: From this biomechanical study, the magnitude of force required to cause suture pullout through the IGHL is met or surpassed by normal postoperative early range-of-motion protocols.

Impact of a stance phase microprocessor-controlled knee prosthesis on level walking in lower functioning individuals with a transfemoral amputation

2013 ◽  
Vol 38 (6) ◽  
pp. 447-455 ◽  
Author(s):  
Valerie J Eberly ◽  
Sara J Mulroy ◽  
JoAnne K Gronley ◽  
Jacquelin Perry ◽  
William J Yule ◽  
...  
Keyword(s):  
Knee Prosthesis ◽  
Knee Extension ◽  
Electromyographic Activity ◽  
Transfemoral Amputation ◽  
Prosthetic Limb ◽  
Level Walking ◽  
Single Limb Support ◽  
Hip Flexion ◽  
The Impact ◽  
Improve Stability

Background: For individuals with transfemoral amputation, walking with a prosthesis presents challenges to stability and increases the demand on the hip of the prosthetic limb. Increasing age or comorbidities magnify these challenges. Computerized prosthetic knee joints improve stability and efficiency of gait, but are seldom prescribed for less physically capable walkers who may benefit from them. Objective: To compare level walking function while wearing a microprocessor-controlled knee (C-Leg Compact) prosthesis to a traditionally prescribed non-microprocessor-controlled knee prosthesis for Medicare Functional Classification Level K-2 walkers. Study design: Crossover. Methods: Stride characteristics, kinematics, kinetics, and electromyographic activity were recorded in 10 participants while walking with non-microprocessor-controlled knee and Compact prostheses. Results: Walking with the Compact produced significant increase in velocity, cadence, stride length, single-limb support, and heel-rise timing compared to walking with the non-microprocessor-controlled knee prosthesis. Hip and thigh extension during late stance improved bilaterally. Ankle dorsiflexion, knee extension, and hip flexion moments of the prosthetic limb were significantly improved. Conclusions: Improvements in walking function and stability on the prosthetic limb were demonstrated by the K-2 level walkers when using the C-Leg Compact prosthesis. Clinical relevance Understanding the impact of new prosthetic designs on gait mechanics is essential to improve prescription guidelines for deconditioned or older persons with transfemoral amputation. Prosthetic designs that improve stability for safety and walking function have the potential to improve community participation and quality of life.

An in vitro biomechanical study of the effects of surgical modification upon the canine lumbosacral spine

2004 ◽  
Vol 17 (01) ◽  
pp. 17-24 ◽  
Author(s):  
T. N. Bebchuk ◽  
C. L. Shmon ◽  
L. G. Watson ◽  
H. Steinmetz ◽  
M. E. H. Smith
Keyword(s):  
Testing Machine ◽  
Biomechanical Study ◽  
Control Group ◽  
Lumbosacral Spine ◽  
Four Point Bending ◽  
Before And After ◽  
Motion Unit ◽  
Dorsal Laminectomy ◽  
The Impact

SummaryThe purpose of this study was to determine the impact of surgical decompressive procedures upon stiffness of cadaveric canine lumbosacral motion units in the dorsoventral plane. Thirty-four grossly normal lumbosacral specimens were potted, in aluminum channeling with polymethylmethacrylate, and subjected to four-point bending in dorsiflexion and ventroflexion, using a universal testing machine (Instron MA). In order to determine its yield point, each specimen was non-destructively tested before and after surgical modification and then tested to failure in ventroflexion. Dorsal laminectomy (L) did not have a significant effect upon stiffness of the lumbosacral motion unit in dorsiflexion or ventroflexion, when compared with the control group. Since this also involved excision of the interspinous and supraspinous ligaments, removal of these structures alone also did not have any significant effect upon dorsoventral stiffness in vitro. Compared with the control group, the stiffness in the other groups changed as follows: addition of discectomy (LD) did not have a statistically significant effect in dorsiflexion, but decreased mean stiffness 33.1% (95% CI 29.0 to 37.2) in ventroflexion. Dorsal laminectomy combined with bilateral facetectomy (LF) decreased stiffness 43.5% (95% CI 39.4 to 47.6) in dorsiflexion, and 30.9% (95% CI 26.8 to 35.0) in ventroflexion. The combination of dorsal laminectomy, facetectomy and discectomy (LFD) decreased the stiffness 47.9% (95% CI 43.8 to 52.0) in dorsiflexion and 56.4% (95% CI 52.3 to 60.5) in ventroflexion. This decrease in stiffness in ventroflexion was significantly greater than with laminectomy and facetectomy alone (25% less stiff; 95% CI 20.9 to 29.1).

scholarly journals Tibiofemoral Cartilage Contact Differences Between Level Walking and Downhill Running

2019 ◽  
Vol 7 (4) ◽  
pp. 232596711983616 ◽  
Author(s):  
Berkcan Akpinar ◽  
Eric Thorhauer ◽  
Scott Tashman ◽  
James J. Irrgang ◽  
Freddie H. Fu ◽  
...  
Keyword(s):  
Contact Area ◽  
Gait Cycle ◽  
Imaging System ◽  
Cartilage Degeneration ◽  
Lateral Compartment ◽  
Medial Compartment ◽  
Downhill Running ◽  
Level Walking ◽  
Impact Phase ◽  
The Impact

Background: Some studies have suggested that altered tibiofemoral cartilage contact behavior (arthrokinematics) may contribute to long-term cartilage degeneration, potentially leading to tibiofemoral osteoarthritis. However, few studies have assessed normal tibiofemoral arthrokinematics during dynamic activities. Purpose: To characterize tibiofemoral arthrokinematics during the impact phase of level walking and downhill running. Study Design: Descriptive laboratory study. Methods: Arthrokinematic data were collected on uninjured knees of 44 participants (mean age, 20.7 ± 6.6 years). Using a dynamic stereoradiographic imaging system with superimposed 3-dimensional bone models from computed tomography and magnetic resonance imaging of participant-specific tibiofemoral joints, arthrokinematics were assessed during the first 15% of the gait cycle during level walking and the first 10% of the gait cycle during downhill running. Results: During level walking and downhill running, the medial compartment had a greater cartilage contact area versus the lateral compartment. Both compartments had a significantly less cartilage contact area during running versus walking (medial compartment gait cycle affected: 8%-10%; lateral compartment gait cycle affected: 5%-10%). Further, medial and lateral compartment tibiofemoral contact paths were significantly more posterior and longer during downhill running. Conclusion: There was a decreased tibiofemoral cartilage contact area during downhill running compared with level walking, suggesting that underlying bone morphology may play a key role in determining the size of cartilage contact regions. Clinical Relevance: This study provides the first data characterizing tibiofemoral cartilage contact patterns during level walking and downhill running. These results provide evidence in support of performing biomechanical assessments during both level walking and downhill running to obtain a comprehensive picture of tibiofemoral cartilage behavior after clinical interventions.

The impact of a distal expansion mechanism added to a standard pedicle screw on pullout resistance. A biomechanical study

2013 ◽  
Vol 13 (5) ◽  
pp. 532-541 ◽  
Author(s):  
Heiko Koller ◽  
Juliane Zenner ◽  
Wolfgang Hitzl ◽  
Herbert Resch ◽  
Daniel Stephan ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Biomechanical Study ◽  
Pullout Resistance ◽  
Expansion Mechanism ◽  
The Impact

scholarly journals SIMULATION OF WEAR IN A SPHERICAL JOINT WITH A POLYMERIC COMPONENT OF THE TOTAL HIP REPLACEMENT CONSIDERING ACTIVITIES OF DAILY LIVING

2018 ◽  
Vol 16 (1) ◽  
pp. 51 ◽  
Author(s):  
Vladimir Pakhaliuk ◽  
Aleksandr Poliakov
Keyword(s):  
Total Hip Replacement ◽  
Hip Replacement ◽  
Daily Living ◽  
Life Time ◽  
Software Systems ◽  
Spherical Joint ◽  
Element Analysis ◽  
Total Hip ◽  
Level Walking ◽  
The Impact

The present study assesses the impact of the main typical activities of patients' daily living (ADL) after total hip arthroplasty (THA) on the wear parameters of sliding couple's materials by simulating linear and volumetric wear according to the Archard's law in a spherical joint with a polymeric element of the total hip replacement (THR). The mathematical wear model, built on the basis of algorithms and custom codes of the finite element analysis in ANSYS and MATLAB software systems, has been studied numerically. The activities used in the model are: level walking, stair ascending-stair descending, chair sitting-chair rising, and deep squatting. They were described by typical waveforms of the angular displacements of the THR's femoral component and the waveforms of the applied force. The results of the simulation show that for the same duration the overall wear value with ADL is significantly higher than in the case of level walking according to the requirements of ISO 14242-1. Therefore, the evaluation of the wear value for ADL is more informative for predicting the functional life time of the THR. Analysis of the simulation results shows that the amount of wear calculated for all activities separately is practically the same as the overall wear value obtained at summary action of ADL. This effect of the independence of contributions to the total amount of wear of each activity makes it possible to significantly simplify the solution of the problem of wear estimation for typical activities, including stochastic ones.

scholarly journals Comprehensive Biomechanism of Impact Resistance in the Cat’s Paw Pad

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Xueqing Wu ◽  
Baoqing Pei ◽  
Yuyang Pei ◽  
Yan Hao ◽  
Kaiyuan Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Early Stage ◽  
Subcutaneous Tissue ◽  
Preliminary Investigation ◽  
Impact Resistance ◽  
Ct Scanning ◽  
Biomechanical Study ◽  
Cylindrical Shape ◽  
Von Mises ◽  
The Impact

Cats are able to jump from a high-rise without any sign of injury, which is attributed in large part to their impact-resistant paw pads. The biomechanical study of paw pads may therefore contribute to improving the impact resistance of specific biomimetic materials. The present study is aimed at investigating the mechanics of the paw pads, revealing their impact-resistant biomechanism from macro- and microscopic perspectives. Histological and micro-CT scanning methods were exploited to analyze the microstructure of the pads, and mechanical testing was conducted to observe the macroscopic mechanical properties at different loading frequencies. Numerical micromodels of the ellipsoidal and cylindrical adipose compartments were developed to evaluate the mechanical functionality as compressive actions. The results show that the stiffness of the pad increases roughly in proportion to strain and mechanical properties are almost impervious to strain rate. Furthermore, the adipose compartment, which comprises adipose tissue enclosed within collagen septa, in the subcutaneous tissue presents an ellipsoid-like structure, with a decreasing area from the middle to the two ends. Additionally, the finite element results show that the ellipsoidal structure has larger displacement in the early stage of impact, which can absorb more energy and prevent instability at touchdown, while the cylindrical structure is more resistant to deformation. Moreover, the Von Mises of the ellipsoidal compartment decrease gradually from both ends to the middle, making it change to a cylindrical shape, and this may be the reason why the macroscopic stiffness increases with increasing time after contact. This preliminary investigation represents the basis for biomechanical interpretation and can accordingly provide new inspirations of shock-absorbing composite materials in engineering.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

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