Normal Six-Degree-of-Freedom Motions of Knee Joint During Level Walking

1996 ◽  
Vol 118 (2) ◽  
pp. 258-261 ◽  
Author(s):  
Xue Mei Li ◽  
Bo Liu ◽  
Bo Deng ◽  
Shi Ming Zhang
Keyword(s):  
Degree Of Freedom ◽  
Joint Measurement ◽  
Knee Motion ◽  
In Vivo Test ◽  
In Vivo Measurement ◽  
Level Walking ◽  
Flexion Extension ◽  
Posterior Translation ◽  
Six Degree Of Freedom

The purpose of this study was to find an effective way for in vivo measurement of joint motion and give the normal knee motion according to this method. The joint model proposed by Grood and Suntay (1983) was chosen; the origin of the tibia was modified for the convenience of in vivo test. A computerized 6 degree-of-freedom electrogoniometer (EGM) was used in the measurement. Repeated tests on one subject were performed to establish the reliability of the method. Knee motions obtained from 42 males during level walking were expressed as flexion-extension, abduction-adduction, external-internal rotation, lateral-medial translation, anterior-posterior translation, and superior-inferior translation. The results showed that, with the proper choice of the origin of the tibia, the EGM could depend much less on external landmarks and be more effective for the joint measurement.

scholarly journals Force Analysis of Human Lumbar Spine Using a Forward Kinematics Model

2021 ◽  
Author(s):  
Krunal Patel
Keyword(s):  
Lumbar Spine ◽  
In Vivo Studies ◽  
Forward Kinematics ◽  
Compression Force ◽  
Trunk Flexion ◽  
Kinematics Model ◽  
In Vivo Measurement ◽  
Human Lumbar Spine ◽  
Flexion Extension

The purpose of this study is to present a forward kinematics model of the human lumbar spine and to compare the internal loads and trunk flexion extension with existing literature. The forward kinematics model of lumbar spine with 30 DOF was designed using Solidworks and used Matlab to simulate the results for different postures. The forward kinematics model predicted similar trend for trunk flexion extension, compression force, shear forces and moment as described in literature for in vivo studies. The comparison between the proposed model and in vivo measurement showed a pressure difference of less than 15% on the disc L4-L5 for all activities whereas the compression force and moment differed by ~17% on the disc L5-S1. The modeling methodology presented in this thesis provides a more accurate representation of compression forces and moments of the human lumbar spine since the model makes no assumptions regarding muscle force and does not rely on any other software for kinematics data.

Effect of Potting Technique on the Measurement of Six Degree-of-Freedom Viscoelastic Properties of Human Lumbar Spine Segments

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Dhara B. Amin ◽  
Isaac M. Lawless ◽  
Dana Sommerfeld ◽  
Richard M. Stanley ◽  
Boyin Ding ◽  
...  
Keyword(s):  
Phase Angle ◽  
Viscoelastic Properties ◽  
Biomechanical Testing ◽  
Axial Rotation ◽  
Intervertebral Discs ◽  
Degree Of Freedom ◽  
Potting Medium ◽  
Significant Difference ◽  
Flexion Extension ◽  
Six Degree Of Freedom

Polymethyl methacrylate (PMMA) and Wood's Metal are fixation media for biomechanical testing; however, the effect of each potting medium on the measured six degree-of-freedom (DOF) mechanical properties of human lumbar intervertebral discs is unknown. The first aim of this study was to compare the measured 6DOF elastic and viscoelastic properties of the disc when embedded in PMMA compared to repotting in Wood's Metal. The second aim was to compare the surface temperature of the disc when potted with PMMA and Wood's Metal. Six human lumbar functional spinal units (FSUs) were first potted in PMMA, and subjected to overnight preload in a saline bath at 37 °C followed by five haversine loading cycles at 0.1 Hz in each of 6DOF loading directions (compression, left/right lateral bending, flexion, extension, left/right axial rotation, anterior/posterior, and lateral shear). Each specimen was then repotted in Wood's Metal and subjected to a 2-h re-equilibrating preload followed by repeating the same 6DOF tests. Outcome measures of stiffness and phase angle were calculated from the final loading cycle in each DOF and were expressed as normalized percentages relative to PMMA (100%). Disc surface temperatures (anterior, left/right lateral) were measured during potting. Paired t-tests (with alpha adjusted for multiple DOF) were conducted to compare the differences in each outcome parameter between PMMA and Wood's Metal. No significant differences in stiffness or phase angle were found between PMMA and Wood's Metal. On average, the largest trending differences were found in the shear DOFs for both stiffness (approximately 35% greater for Wood's Metal compared to PMMA) and phase angle (approximately 15% greater for Wood's Metal). A significant difference in disc temperature was found at the anterior surface after potting with Wood's Metal compared to PMMA, which did not exceed 26 °C. Wood's Metal is linear elastic, stiffer than PMMA and may reduce measurement artifact of potting medium, particularly in the shear directions. Furthermore, it is easier to remove than PMMA, reuseable, and cost effective.

Motion Analysis Evaluation of Knee Braces During Level Walking

1997 ◽  
Vol 01 (01) ◽  
pp. 71-80
Author(s):  
F. C. Su ◽  
C. H. Lin
Keyword(s):  
Knee Joint ◽  
Motion Analysis ◽  
Cruciate Ligament ◽  
Control Group ◽  
Helical Axis ◽  
Injured Limb ◽  
Knee Motion ◽  
Level Walking ◽  
Flexion Extension ◽  
Knee Braces

The purpose of this study is to evaluate the influence of two currently available rehabilitative knee braces on knee motion and their ability to protect against the knee displacement. Using the Eulerian angle, finite helical axis and three-dimensional motion analysis system, we measured all six degrees of freedom (DOF) of knee motion during level walking. The experimental group consisted of seven left anterior cruciate ligament deficient patients. Six normal subjects comprised the control group. Four test conditions were investigated: 1) injured limb; 2) injured limb with a range of motion (ROM) splint; 3) injured limb with 4-Point brace; and 4) control limb. Among the three knee joint angles, the maximal change induced by the brace occurred in flexion/extension, whereas the minimum occurred in abduction / adduction. Among the three translations, the maximal change appeared in the anterior / posterior displacement, whereas the minimum appeared in the medial / lateral displacement. Both knee braces were shown to significantly reduce three rotations and three translations of knee motion. The ROM splint restricted more knee motion than 4-Point brace, but no noticeable changes in the kinematic patterns, walking speed, and the percentage of left or right stance phase in the gait cycle could be demonstrated between two designs. In vivo measurements of translation of knee joint gave important information in the study of cruciate ligament injury problems or knee brace design.

scholarly journals Force Analysis of Human Lumbar Spine Using a Forward Kinematics Model

2021 ◽  
Author(s):  
Krunal Patel
Keyword(s):  
Lumbar Spine ◽  
In Vivo Studies ◽  
Forward Kinematics ◽  
Compression Force ◽  
Trunk Flexion ◽  
Kinematics Model ◽  
In Vivo Measurement ◽  
Human Lumbar Spine ◽  
Flexion Extension

The purpose of this study is to present a forward kinematics model of the human lumbar spine and to compare the internal loads and trunk flexion extension with existing literature. The forward kinematics model of lumbar spine with 30 DOF was designed using Solidworks and used Matlab to simulate the results for different postures. The forward kinematics model predicted similar trend for trunk flexion extension, compression force, shear forces and moment as described in literature for in vivo studies. The comparison between the proposed model and in vivo measurement showed a pressure difference of less than 15% on the disc L4-L5 for all activities whereas the compression force and moment differed by ~17% on the disc L5-S1. The modeling methodology presented in this thesis provides a more accurate representation of compression forces and moments of the human lumbar spine since the model makes no assumptions regarding muscle force and does not rely on any other software for kinematics data.

scholarly journals Validation of a portable marker-based motion analysis system

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shaobai Wang ◽  
Xiaolong Zeng ◽  
Liang Huangfu ◽  
Zhenyan Xie ◽  
Limin Ma ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
External Rotation ◽  
Pearson Correlation ◽  
Knee Kinematics ◽  
Level Walking ◽  
Flexion Extension ◽  
Two Systems ◽  
Posterior Translation ◽  
Analysis System ◽  
Biplanar Fluoroscopy

Abstract Background The Opti_Knee system, a marker-based motion capture system, tracks and analyzes the 6 degrees of freedom (6DOF) motion of the knee joint. However, the validation of the accuracy of this gait system had not been previously reported. The objective of this study was to validate and the system. Two healthy subjects were recruited for the study. Methods The 6DOF kinematics of the knee during flexion–extension and level walking cycles of the knee were recorded by Opti_Knee and compared to those from a biplanar fluoroscopy system. The root mean square error (RMSE) of knee kinematics in flexion–extension cycles were compared between the two systems to validate the accuracy at which they detect basic knee motions. The RMSE of kinematics at key events of gait cycles (level walking) were compared to validate the accuracy at which the systems detect functional knee motion. Pearson correlation tests were conducted to assess similarities in knee kinematic trends between the two systems. Results In flexion–extension cycles, the average translational accuracy (RMSE) was between 2.7 and 3.7 mm and the average rotational accuracy was between 1.7 and 3.8°. The Pearson correlation of coefficients for flexion–extension cycles was between 0.858 and 0.994 for translation and 0.995-0.999 for angles. In gait cycles, the RMSEs of angular knee kinematics were 2.3° for adduction/abduction, 3.2° for internal/external rotation, and 1.4° for flexion/extension. The RMSEs of translational kinematics were 4.2 mm for anterior/posterior translation, 3.3 mm for distal/proximal translation, and 3.2 mm for medial/lateral translation. The Pearson correlation of coefficients values was between 0.964 and 0.999 for angular kinematics and 0.883 and 0.938 for translational kinematics. Conclusion The Opti_Knee gait system exhibited acceptable accuracy and strong correlation strength compared to biplanar fluoroscopy. The Opti _Knee may serve as a promising portable clinical system for dynamic functional assessments of the knee.

A Finite Helical Axis as a Landmark for Kinematic Reference of the Knee

1991 ◽  
Vol 113 (2) ◽  
pp. 215-222 ◽  
Author(s):  
R. A. Hart ◽  
C. D. Mote ◽  
H. B. Skinner
Keyword(s):  
Soft Tissue ◽  
Human Subjects ◽  
Helical Axis ◽  
Knee Motion ◽  
Axis Orientation ◽  
Motion Representation ◽  
Axial Translation ◽  
Six Degree Of Freedom ◽  
Finite Helical Axis

Reference coordinates based on the finite helical axis for flexion of the knee from 0 to 90 deg are proposed. Six degree-of-freedom tracking allows the use of such a helical axis as a kinematic landmark for knee motion representation. Data from five human subjects in vivo are presented as a path of finite helical axes for flexion of the knee from 20 to 80 deg. The finite helical axis rotates by an average of 11.4 deg, the centrode translates an average of 19.8 mm, and the total axial translation averages 0.1 mm during flexion from 20 to 80 deg. Error due to the transducer was measured on a fixed-pivot pendulum and found to be 1.0 deg and 1.9 mm rms for the helical axis orientation and position, respectively, and 0.1 mm for the axial translation. Reproducibility and soft tissue effects on the measurements were repeatable to 4.0 deg and 2.7 mm rms in orientation and position, respectively, and 0.1 mm for the axial translations. Soft tissue errors averaged 4.9 deg and 3.6 mmm in position and orientation, and 0.3 mm in the axial translations.

scholarly journals In vivo six-degree-of-freedom knee-joint kinematics in overground and treadmill walking following total knee arthroplasty

2016 ◽  
Vol 35 (8) ◽  
pp. 1634-1643 ◽  
Author(s):  
Shanyuanye Guan ◽  
Hans A. Gray ◽  
Anthony G. Schache ◽  
Julian Feller ◽  
Richard de Steiger ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Joint ◽  
Knee Arthroplasty ◽  
Joint Kinematics ◽  
Treadmill Walking ◽  
Degree Of Freedom ◽  
Knee Joint Kinematics ◽  
Total Knee ◽  
Six Degree Of Freedom

Development of a six station knee wear simulator and preliminary wear results

1997 ◽  
Vol 211 (1) ◽  
pp. 37-47 ◽  
Author(s):  
I C Burgess ◽  
M Kolar ◽  
J L Cunningham ◽  
A Unsworth
Keyword(s):  
Ex Vivo ◽  
Wear Test ◽  
Total Knee Replacements ◽  
Delamination Wear ◽  
Knee Simulator ◽  
Flexion Extension ◽  
Posterior Translation ◽  
Anterior Posterior

In order to assess the wear performance of different designs of total knee replacements (TKR), a six station multi-axis knee simulator has been designed, built and commissioned. The most important features of a knee simulator are representative angles of flexion-extension synchronized with a dynamically applied load, and a combination of rolling and sliding motion. The simulator typically applies flexion-extension of 0-65°, anterior-posterior translation of up to 15 mm, a dynamic load of up to 5.0 kN, and operates at 1.0 Hz. The loads and motions are applied using computer controlled servohydraulic actuators and hence their profiles are easily modified. A preliminary wear test has been conducted using a Kinemax (Howmedica, United Kingdom) TKR. The test was conducted in 30 per cent bovine serum which was changed every 150 000 cycles, at which time the bearing surfaces were examined and the UHMWPE tibial component was weighed. Over eight million cycles, a tibial wear rate of 2.62 mg/106 cycles was measured. The mild wear observed was characterized by burnishing and slight scratching in the anterior-posterior direction. These observations are broadly in line with both in vitro and ex vivo studies reported in the literature for this type of prosthesis. Delamination wear sometimes observed in vivo was not seen.

Defibrotide Inhibits Platelet Activation by Cathepsin G Released From Stimulated Polymorphonuclear Leukocytes

1992 ◽  
Vol 67 (06) ◽  
pp. 660-664 ◽  
Author(s):  
Virgilio Evangelista ◽  
Paola Piccardoni ◽  
Giovanni de Gaetano ◽  
Chiara Cerletti
Keyword(s):  
Platelet Activation ◽  
Polymorphonuclear Leukocytes ◽  
Direct Interaction ◽  
Cathepsin G ◽  
In Vivo Test ◽  
Cell Functions ◽  
Test Models ◽  
Antithrombotic Effects

SummaryDefibrotide is a polydeoxyribonucleotide with antithrombotic effects in experimental animal models. Most of the actions of this drug have been observed in in vivo test models but no effects have been reported in in vitro systems. In this paper we demonstrate that defibrotide interferes with polymorphonuclear leukocyte-induced human platelet activation in vitro. This effect was not related to any direct interaction with polymorphonuclear leukocytes or platelets, but was due to the inhibition of cathepsin G, the main biochemical mediator of this cell-cell cooperation. Since cathepsin G not only induces platelet activation but also affects some endothelial cell functions, the anticathepsin G activity of defibrotide could help to explain the antithrombotic effect of this drug.

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