Reaction Forces and Flexion-Extension Moments Imposed On Functional Spinal Units with Constrained and Unconstrained in Vitro Testing Systems

2021 ◽  
Author(s):  
Jackie D. Zehr ◽  
Jack P. Callaghan
Keyword(s):  
Dynamic Compression ◽  
Peak Load ◽  
In Vitro Testing ◽  
Floating Base ◽  
Flexion Extension ◽  
Fixed Base ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Six Degree Of Freedom

Abstract A mechanical goal of in vitro testing systems is to minimize differences between applied and actual forces and moments experienced by spinal units. This study quantified the joint reaction forces and reaction flexion-extension moments during dynamic compression loading imposed throughout the physiological flexion-extension range-of-motion. Constrained (fixed base) and unconstrained (floating base) testing systems were compared. Sixteen porcine spinal units were assigned to both testing groups. Following conditioning tests, specimens were dynamically loaded for 1 cycle with a 1 Hz compression waveform to a peak load of 1 kN and 2 kN while positioned in five different postures (neutral, 100% and 300% of the flexion and extension neutral zone), totalling ten trials per FSU. A six degree-of-freedom force and torque sensor was used to measure peak reaction forces and moments for each trial. Shear reaction forces were significantly greater (25.5 N - 85.7 N) when the testing system was constrained compared to unconstrained (p < 0.029). The reaction moment was influenced by posture (p = 0.037), particularly in C5C6 spinal units. In 300% extension (C5C6), the reaction moment was, on average, 9.9 Nm greater than the applied moment in both testing systems and differed from all other postures (p < 0.001). The reaction moment error was, on average, 0.45 Nm at all other postures. In conclusion, these findings demonstrate that comparable reaction moments can be achieved with unconstrained systems, but without inducing appreciable shear reaction forces.

Prediction of Antagonistic Muscle Forces Using Inverse Dynamic Optimization During Flexion/Extension of the Knee

1999 ◽  
Vol 121 (3) ◽  
pp. 316-322 ◽  
Author(s):  
G. Li ◽  
K. R. Kaufman ◽  
E. Y. S. Chao ◽  
H. E. Rubash
Keyword(s):  
Dynamic Optimization ◽  
Optimization Procedure ◽  
Muscle Forces ◽  
Inverse Dynamic ◽  
Optimization Criteria ◽  
Flexion Extension ◽  
Antagonistic Muscle ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Joint Reaction

This paper examined the feasibility of using different optimization criteria in inverse dynamic optimization to predict antagonistic muscle forces and joint reaction forces during isokinetic flexion/extension and isometric extension exercises of the knee. Both quadriceps and hamstrings muscle groups were included in this study. The knee joint motion included flexion/extension, varus/valgus, and internal/external rotations. Four linear, nonlinear, and physiological optimization criteria were utilized in the optimization procedure. All optimization criteria adopted in this paper were shown to be able to predict antagonistic muscle contraction during flexion and extension of the knee. The predicted muscle forces were compared in temporal patterns with EMG activities (averaged data measured from five subjects). Joint reaction forces were predicted to be similar using all optimization criteria. In comparison with previous studies, these results suggested that the kinematic information involved in the inverse dynamic optimization plays an important role in prediction of the recruitment of antagonistic muscles rather than the selection of a particular optimization criterion. Therefore, it might be concluded that a properly formulated inverse dynamic optimization procedure should describe the knee joint rotation in three orthogonal planes.

Estimation of Shoulder Joint Reaction Forces and Moments Using MBS Dynamic Modeling

2014 ◽  
Vol 555 ◽  
pp. 701-706 ◽  
Author(s):  
Elena Mereuta ◽  
Daniel Ganea ◽  
Claudiu Mereuta
Keyword(s):  
Upper Limb ◽  
Shoulder Joint ◽  
Driving Force ◽  
Biceps Muscle ◽  
The Third ◽  
Flexion Extension ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Human Upper Limb ◽  
Joint Reaction

The paper presents a dynamic model created for estimating the magnitude of reaction forces and moments in the shoulder joint of the human upper limb. Considering that the flexion-extension motion of the forearm is simulated under three different conditions, the reaction forces and moments are determined. The first actuating case is corresponding to the case in which the driving force is acting on the long end of the biceps muscle. In the second case the driving force is acting on the short end of the biceps muscle, and in the third case the driving force is acting on both ends of the biceps muscle.

scholarly journals Biomechanics of hip joint: a systematic review

2018 ◽  
Vol 7 (3) ◽  
pp. 1672 ◽  
Author(s):  
Chethan KN ◽  
Shyamasunder Bhat N ◽  
Satish Shenoy B
Keyword(s):  
Hip Joint ◽  
Living Organism ◽  
Upper Body ◽  
Joint Prosthesis ◽  
Load Carrying ◽  
Different Types ◽  
Joint Reaction Forces ◽  
Reaction Forces

Hip joint is the second largest joint in human after knee joint. It is associated with different types of motion which helps in the movement of human body and provide stability. Biomechanics involves the study of movement of living organism. It is important to know and understand the basics of biomechanics of hip joint to define the movement of hip joint along with its load carrying capacity in different day to day activities. Many researchers are worked to know the basics biomechanics of hip joint both in in-vitro and in- vivo conditions. In this paper, it has been reported in detail to know the different biomechanical aspects involved in the hip joint during different movement and also different biomaterials used in the hip joint prosthesis. It is majorly focused on load transmitting by hip joint by upper body to lower body in different activities such as walking, running, stumbling etc. So, these basic understanding helps to understand effectively the joint reaction forces which is acting on hip joint while designing new hip joint prosthesis.  

In Vitro Measurement of the Tracking Pattern of the Human Patella

1999 ◽  
Vol 121 (2) ◽  
pp. 222-228 ◽  
Author(s):  
A. M. Ahmed ◽  
N. A. Duncan ◽  
M. Tanzer
Keyword(s):  
Coefficient Of Variation ◽  
Normal Population ◽  
General Pattern ◽  
Three Dimensional ◽  
Knee Extension ◽  
Flexion Extension ◽  
Average Coefficient ◽  
Fresh Frozen ◽  
Six Degree Of Freedom

This study sought to determine whether a general pattern describing the three-dimensional tracking characteristics of the human patella could be established, and if not, then to determine the extent and nature of interspecimen variations in the characteristics in a normal population. Using 32 fresh-frozen knees subjected to extensor moment magnitudes similar to those in “static-lifting” and “leg-raising against resistance” maneuvers, patellar displacements were measured in the knee extension range 120 to 0 deg. For static-lifting, a constant foot-floor reaction of 334 N was applied. For leg-raising, a constant net quadriceps tension of 668 N was used throughout the extension range. Measurements were taken with a calibrated six-degree-of-freedom electromechanical goniometer and a displacement coordinate system referenced to the geometry of individual specinens. The three patellar displacements in the plane of knee extension/flexion (extension rotation, and anterior and proximal translations) consistently demonstrated the same pattern in the entire knee extension range with an average coefficient of variation of 13 percent. For knee angles greater than 45 deg, the three other displacements (medial lateral translation, and rotations about the anterior–posterior and proximal–distal axes) followed a general pattern. However, for knee angles less than 45 deg, these displacements differed considerably between specimens for each loading condition, both in terms of magnitude (average coefficient of variation: 70 percent), and direction.

scholarly journals A Critical Analysis of TKR In Vitro Wear Tests Considering Predicted Knee Joint Loads

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1597 ◽  
Author(s):  
Saverio Affatato ◽  
Alessandro Ruggiero
Keyword(s):  
Knee Joint ◽  
Detailed Knowledge ◽  
Musculoskeletal Modelling ◽  
Assessment Protocol ◽  
Joint Forces ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Wear Tests

Detailed knowledge about loading of the knee joint is essential for preclinical testing of total knee replacement. Direct measurement of joint reaction forces is generally not feasible in a clinical setting; non-invasive methods based on musculoskeletal modelling should therefore be considered as a valid alternative to the standards guidelines. The aim of this paper is to investigate the possibility of using knee joint forces calculated through musculoskeletal modelling software for developing an in vitro wear assessment protocol by using a knee wear simulator. In particular, in this work we preliminarily show a comparison of the predicted knee joint forces (in silico) during the gait with those obtained from the ISO 14243-1/3 and with those measured in vivo by other authors. Subsequently, we compare the wear results obtained from a knee wear joint simulator loaded by calculated forces in correspondence to the “normal gait” kinematics with those obtained in correspondence to the loads imposed by the ISO. The obtained results show that even if the predicted load profiles are not totally in good agreement with the loads deriving from ISO standards and from in vivo measurements, they can be useful for in vitro wear tests, since the results obtained from the simulator in terms of wear are in agreement with the literature data.

scholarly journals Incorporating Six Degree-of-Freedom Intervertebral Joint Stiffness in a Lumbar Spine Musculoskeletal Model—Method and Performance in Flexed Postures

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Xiangjie Meng ◽  
Alexander G. Bruno ◽  
Bo Cheng ◽  
Wenjun Wang ◽  
Mary L. Bouxsein ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Compressive Loading ◽  
Joint Stiffness ◽  
Musculoskeletal Model ◽  
Implant Design ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
And Performance ◽  
Six Degree Of Freedom

Intervertebral translations and rotations are likely dependent on intervertebral stiffness properties. The objective of this study was to incorporate realistic intervertebral stiffnesses in a musculoskeletal model of the lumbar spine using a novel force-dependent kinematics approach, and examine the effects on vertebral compressive loading and intervertebral motions. Predicted vertebral loading and intervertebral motions were compared to previously reported in vivo measurements. Intervertebral joint reaction forces and motions were strongly affected by flexion stiffness, as well as force–motion coupling of the intervertebral stiffness. Better understanding of intervertebral stiffness and force–motion coupling could improve musculoskeletal modeling, implant design, and surgical planning.

Urokinase Evaluated with the Experimental Radioactive Embolus

1967 ◽  
Vol 17 (03/04) ◽  
pp. 405-411
Author(s):  
M Hume
Keyword(s):  
Animal Experiment ◽  
Blood Clot ◽  
In Vitro Testing ◽  
Effective Agent

SummaryUrokinase and urokinase-activated plasmin have been given to the dog and rabbit. A thrombolytic state has been induced. Purified urokinase has induced lysis of the experimental radioactive blood clot embolus in the circulation. Demonstration of effectiveness in this animal experiment is hampered by inhibition of the agents in the circulation to a degree much greater than was noted in previous experiments with streptokinase. In vitro testing indicates that under proper conditions urokinase will be an effective agent in the treatment of human thromboembolism.

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