Effect of Fixed Axes of Rotation on the Varus-Valgus and Torsional Load-Displacement Characteristics of the In-Vitro Human Knee

1979 ◽  
Vol 101 (2) ◽  
pp. 134-140 ◽  
Author(s):  
J. Rastegar ◽  
R. L. Piziali ◽  
D. A. Nagel ◽  
D. J. Schurman
Keyword(s):  
Least Squares ◽  
Cubic Spline ◽  
Nonlinear Load ◽  
Human Knee ◽  
Torsional Load ◽  
Axis Of Rotation ◽  
Second Derivatives ◽  
Load Displacement ◽  
Coupled Loads

The effects of fixed axes of rotation on the varus-valgus and torsional load-displacement characteristics of the human knee have been determined. The location of the axes of varus-valgus and torsional rotations resulting in minimum resisting loads are also determined, and it is shown that they correspond to minimal coupled load levels. The coupled loads are seen to be sensitive to the location of the axis of rotation. The nonlinear load-displacement data is fitted with a four interval least-squares cubic spline with matching first and second derivatives at nodes. The data from two fresh human knees are presented.

An Apparatus for Measuring the Load-Displacement and Load-Dependent Kinematic Characteristics of Articulating Joints—Application to the Human Ankle Joint

1980 ◽  
Vol 102 (3) ◽  
pp. 208-213 ◽  
Author(s):  
J. Rastegar ◽  
N. Miller ◽  
R. Barmada
Keyword(s):  
Ankle Joint ◽  
Structural Characteristics ◽  
Accurate Description ◽  
Axis Of Rotation ◽  
Kinematic Characteristics ◽  
Joint Resistance ◽  
Human Ankle ◽  
Load Displacement ◽  
Coupled Loads

An apparatus is described which is capable of measuring the load-displacement characteristics as well as determining the loci of centers of rotation of articulating joints. The apparatus employs a floating head which permits the axis of rotation to coincide with the position of minimum joint resistance, thus eliminating non-physiological rotations at the joint. The coupled loads are also measured, thus providing an accurate description of the joint structural characteristics. Data taken from a freshly amputated human ankle joint is presented.

The Three-Dimensional Kinematics and Flexibility Characteristics of the Human Ankle and Subtalar Joint—Part II: Flexibility Characteristics

1988 ◽  
Vol 110 (4) ◽  
pp. 374-385 ◽  
Author(s):  
Jie Chen ◽  
Sorin Siegler ◽  
Carson D. Schneck
Keyword(s):  
Ankle Joint ◽  
Angular Displacement ◽  
Three Dimensional ◽  
Anterior Talofibular Ligament ◽  
Neutral Position ◽  
Nonlinear Load ◽  
Highly Nonlinear ◽  
Human Ankle ◽  
Load Displacement

The objective of the present study was to investigate the in-vitro, coupled, three-dimensional load-displacement and flexibility characteristics of the human ankle joint complex consisting of the talocrural and the talocalcaneal joints and to determine the effects that sectioning of the anterior talofibular ligament has on these characteristics. Similar to other anatomical joints such as the knee and the intervertebral joint, the ankle joint complex was found to exhibit highly nonlinear load-displacement characteristics with the angular displacement approaching asymptotic values as the external load was increased. Therefore, a procedure of incremental linearization was used to derive the flexibility characteristics of this structure. According to this procedure, external loads were applied to the calcaneus in small increments and its resulting three dimensional displacements were recorded. The incremental flexibility coefficients were then derived by assuming linear load-displacement relationship for each increment. From the results obtained from fifteen human ankle specimens, it was evident that the ankle joint complex exhibit highly coupled flexibility and load-displacement characteristics. It was further concluded that the ankle joint complex is the most flexible in the neighborhood of the unloaded, neutral position and that all the flexibility coefficients of the structure decrease rapidly toward the extremes of the range of motion. Rupture of the anterior talofibular ligament was found to have a significant effect on the load-displacement and flexibility characteristics of the ankle joint complex. This effect was manifested as a change in the load-displacement characteristics and a large increase in the flexibility coefficients primarily in those corresponding to rotations in the transverse and the coronal plane. The results of the present study can provide the necessary data base for the development of quantitative diagnostic technique for identifying the site and the extent of injury to the collateral ligaments of the ankle.

Cervical Plate Stiffness Affects the Distribution of Loads and the Location of the Instantaneous Axis of Rotation of the Spine In Vitro

2016 ◽  
Vol 16 (10) ◽  
pp. S260-S261 ◽  
Author(s):  
Josh Peterson ◽  
Carolyn Chlebek ◽  
Ashley Clough ◽  
Alexandra Wells ◽  
Eric H. Ledet
Keyword(s):  
Instantaneous Axis Of Rotation ◽  
Axis Of Rotation ◽  
Cervical Plate ◽  
Instantaneous Axis

A New Load Application System for In Vitro Study of Ligamentous Injuries to the Human Knee Joint

1995 ◽  
Vol 117 (4) ◽  
pp. 373-382 ◽  
Author(s):  
J. M. Bach ◽  
M. L. Hull
Keyword(s):  
Knee Joint ◽  
Degree Of Freedom ◽  
Load Application ◽  
Accuracy Evaluation ◽  
Application System ◽  
Human Knee ◽  
Human Knee Joint ◽  
Flexion Extension ◽  
External Loads

This paper describes the design and accuracy evaluation of a new six degree of freedom load application system for in vitro testing of the human knee joint. External loads of both polarity in all six degrees of freedom can be applied either individually or in any combination while the knee is permitted to move unconstrained in response to applied loads. The flexion/extension degree of freedom permits the full physiological range of motion. In addition to external loads, forces of the three major muscle groups (quadriceps, hamstrings, gastrocnemius) crossing the joint can be developed. Full automation and rapid convergence of loads to programmed values are achieved through a computer which feeds command signals to servo controller/electro-pneumatic servo valves. The servo valves regulate pressure to pneumatic actuators which develop the various loads. Experiments undertaken to quantify the accuracy of both load and displacement measurements reveal that errors particularly in load measurement are effectively controlled through the apparatus design.

scholarly journals An Experimental Approach to Evaluate the Dynamic Behavior of the Human Knee

1988 ◽  
Vol 110 (1) ◽  
pp. 69-73 ◽  
Author(s):  
H. W. J. Jans ◽  
L. J. M. G. Dortmans ◽  
A. A. H. J. Sauren ◽  
A. Huson
Keyword(s):  
Experimental Approach ◽  
Function Analysis ◽  
Measuring System ◽  
Dynamic Force ◽  
Force Transmission ◽  
Human Knee ◽  
Human Knee Joint ◽  
In Vitro Investigation ◽  
Transfer Function Analysis

An experimental approach for an in vitro investigation of some aspects of dynamic force transmission through the human knee joint is presented. Essentially, the behavior of the joint was analyzed by measuring the responses to low level random excitation of the tibia while the femur was clamped. A global equilibrium position of the joint was attained by exerting static forces on the tibia via three tendinous muscle attachments. The responses to the applied dynamic loads were measured using a multi-channel dynamic measuring system and quantified by means of transfer function analysis techniques. Some preliminary experimental results are presented to illustrate the effects of variation of the direction and the magnitude of the applied dynamic and static loads.

282 DIFFERENT CONCENTRATIONS OF FORSKOLIN FOR MEIOSIS BLOCK AND TO IMPROVE IN VITRO PRODUCTION OF BOVINE EMBRYOS

2015 ◽  
Vol 27 (1) ◽  
pp. 230
Author(s):  
D. Paschoal ◽  
R. Maziero ◽  
M. Sudano ◽  
M. Guastali ◽  
L. Crocomo ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Least Squares ◽  
Control Group ◽  
In Vitro Production ◽  
Intact Cells ◽  
Significance Level ◽  
Nuclear Maturation ◽  
Oocyte Meiosis ◽  
Group Control

The inhibition of nuclear maturation allows time for the oocyte to accumulate molecules that are important for embryonic development. It was suggested that the inhibition of spontaneous nuclear IVM might allow for more time to accumulate the molecules important for embryonic development. The objective of this work was to evaluate blocking oocyte meiosis with the addition of forskolin. Slaughterhouse-derived bovine Zebu ovaries were collected and carried to the laboratory. Oocytes (n = 584) with at least 3 intact layers of cumulus cells and homogeneous cytoplasm were selected for IVM. The oocytes were transferred to drops of TCM 199 plus 10% FCS and hormones. The oocytes remained in IVM medium in 3 different concentrations of forskolin (6886), 0.1, 0.05, 0.025 mM, and a control group (withouth forskolin), for 6 h. Then they were maturated for an additional 18 h in forskolin-free medium. The first period above was an attempt to block (Block) and the second to resume (Res) the oocyte meiosis. The oocytes were incubated in a humidified atmosphere with 5% CO2 at 38.5°C in an air incubator. The oocytes were assessed for the stage of nuclear maturation, to see if they were in M II. Then oocytes were in vitro fertilized (IVF) with frozen Nelore bull semen (Bos taurus indicus). Presumptive zygotes (20–30/group) were cultured in SOFaa (synthetic oviducal fluid) supplemented with 5 mg mL–1 of BSA; the embryos were kept in an incubator with 5% CO2, 5% O2, and 90% N2 at 38.5°C and absolute humidity. On Day 7 (Day 0 = IVF) the blastocyst, the number of viable cells, and apoptosis rate (terminal deoxynucleotide transferase uridine nick-end labelling) were observed. Data were analysed with ANOVA using SAS PROC GLM (SAS Inst. Inc., Cary, NC, USA). Sources of variation in the model, including treatment and replication, were respectively considered fixed and random effects. If ANOVA was significant, the contrasts of means were performed using the least-squares difference. Data are presented as the mean and the standard error of least-squares. For all analyses, we used a significance level of 5%. No differences were observed for the stage of nuclear maturation of the oocyte (N = 336; control: 67.7 ± 8.3; F 0.025 mM, Block/Res: 67.7 ± 8.9; F 0.05 mM, Block/Res: 65.9 ± 9.8; F 0.1 mM, Block/Res: 50.2 ± 8.9), the blastocyst rate (N = 584; Control: 36.7 ± 3.7; F0.025 mM, Block/Res: 32.6 ± 3.7; F0.05 mM, Block/Res: 29.2 ± 3.7; F0.1 mM, Block/Res: 25.1 ± 3.7), and total number of intact cells (N = 10–15 embryos/group; Control:140.1 ± 13.0; F0.025 mM, Block/Res: 129.9 ± 13.0; F0.05 mM, Block/Res: 139.0 ± 13.0; F0.1 mM, Block/Res: 104.4 ± 13.0; P > 0.05). However, a higher rate of apoptosis was observed in the blastocysts produced from oocytes blocked for 6 h with the higher concentration of forskolin (N = 10–15 embryos/group): Control: 12.1 ± 2.5a; F 0.025 mM, Block/Res: 12.9 ± 2.5a; F0.05 mM, Block/Res: 13.5 ± 2.5a; F 0.1 mM, Block/Res: 30.2 ± 2.5b (P < 0.05). We conclude that all the experimental groups reached the stage of M II after the addition of forskolin and the highest concentration of forskolin caused cellular degeneration without harming embryo production on the seventh day.

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