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.

Nonlinear behavior of muscle reflexes at the human ankle joint

1995 ◽  
Vol 73 (1) ◽  
pp. 65-72 ◽  
Author(s):  
R. B. Stein ◽  
R. E. Kearney
Keyword(s):  
Ankle Joint ◽  
Stretch Reflex ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Random Perturbations ◽  
Hydraulic Actuator ◽  
Voluntary Activity ◽  
Highly Nonlinear ◽  
Human Ankle

1. Pulse inputs (similar to tendon jerks) were applied to the human ankle joint with the use of a hydraulic actuator. Inputs of only 1-2 degrees could elicit large responses (> 20% of maximum voluntary contraction). The magnitude of the response depended nonlinearly on a number of factors: the amplitude, direction, and duration of the pulse; the angle of the ankle; and the level of voluntary activation of the ankle muscles. 2. Pulses that flexed or extended the ankle could both produce reflex torques in the same direction (extensor torque). Although an extension of the ankle did not itself produce a response, it could affect the response to a subsequent flexion for up to 1 s. 3. The influence of random perturbations on the stretch reflex at the ankle was assessed. Responses to pulse displacements alone and to pulses superimposed on random perturbations were compared at the same level of voluntary activity. Reflex responses decreased in a graded manner with increasing amplitude or bandwidth of the random perturbations. 4. These results demonstrate that stretch reflexes can generate substantial torques, but in a highly nonlinear manner. In particular, passive joint movements markedly alter stretch reflex gain, and these changes must be considered in interpreting the functional significance of reflex actions.

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.

scholarly journals Iterative strategies associated with the normal flow technique on the nonlinear analysis of structural arches

2014 ◽  
Vol 67 (2) ◽  
pp. 143-150 ◽  
Author(s):  
Dalilah Pires Maximiano ◽  
Andréa Regina Dias da Silva ◽  
Ricardo Azoubel da Mota Silveira
Keyword(s):  
Iterative Scheme ◽  
Displacement Curve ◽  
Equilibrium Path ◽  
Normal Flow ◽  
Nonlinear Load ◽  
Nonlinear Solution ◽  
Highly Nonlinear ◽  
Newton Raphson ◽  
Load Displacement ◽  
Path Following Methods

A large part of the numerical procedures for obtaining the equilibrium path or load-displacement curve of structural problems with static nonlinear behavior is based on the Newton-Raphson iterative scheme to which are coupled the path-following methods. In this context, this study uses one technique, referred to as normal flow, in the process of obtaining the approximate nonlinear static response of structural systems. Basically, this technique is an adaptation made with in the Newton-Raphson iterative scheme in an attempt to speed up the nonlinear solution process and/or remove convergence problems. To overcome the critical points and to trace the whole nonlinear equilibrium path, three different strategies are used in association with the normal flow technique: the cylindrical arc-length, the minimum residual displacement norm and the generalized displacement. With this procedure, the performance of these strategies when associated with the normal flow technique is valued. Two arches with highly nonlinear load-displacement curves are used in the study. The results obtained demonstrated that the association of the generalized displacement strategy with the normal flow technique contributes to the improvement of the nonlinear solution methodology.

The Effect of Subtalar Arthrodesis Alignment on Ankle Biomechanics

2012 ◽  
Author(s):  
James R. Jastifer ◽  
Peter A. Gustafson ◽  
Robert R. Gorman
Keyword(s):  
Lower Extremity ◽  
Range Of Motion ◽  
Ankle Joint ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Neutral Position ◽  
Moment Arms ◽  
Subtalar Arthrodesis ◽  
Force Moment ◽  
Ankle Biomechanics

Background: The position, axis, and control of each lower extremity joint intimately affects adjacent joint function as well as whole limb performance. There is little describing the biomechanics of subtalar arthrodesis and none describing the effect that subtalar arthrodesis position has on ankle biomechanics. The purpose of the current study is to establish this effect on sagittal plane ankle biomechanics. Methods: A study was performed utilizing a three-dimensional, validated, computational model of the lower extremity. A subtalar arthrodesis was simulated from 20 degrees of varus to 20 degrees of valgus. For each of these subtalar arthrodesis positions, the ankle dorsiflexor and plantarflexor muscles’ fiber force, moment arm, and moments were calculated throughout a physiologic range of motion. Results: Throughout ankle range of motion, plantarflexion and dorsiflexion strength varies with subtalar arthrodesis position. When the ankle joint is in neutral position, plantarflexion strength is maximized in 10 degrees of subtalar valgus and strength varies by a maximum of 2.6% from the peak 221 Nm. In a similar manner, with the ankle joint in neutral position, dorsiflexion strength is maximized with a subtalar joint arthrodesis in 5 degrees of valgus and strength varies by a maximum of 7.5% from the peak 46.8 Nm. The change in strength is due to affected muscle fiber force generating capacities and muscle moment arms. Conclusion: The clinical significance of this study is that subtalar arthrodesis in a position of 5–10 degrees subtalar valgus has biomechanical advantage. This supports previous clinical outcome studies and offers biomechanical rationale for their generally favorable outcomes.

Influence of the Interosseous Talocalcaneal Ligament Injury on Stability of the Ankle-Subtalar Joint Complex — a Cadaveric Experimental Study

2000 ◽  
Vol 21 (6) ◽  
pp. 486-491 ◽  
Author(s):  
Yuki Tochigi ◽  
Kazuhisa Takahashi ◽  
Masatsune Yamagata ◽  
Tamotsu Tamaki
Keyword(s):  
Ankle Joint ◽  
Subtalar Joint ◽  
Plantar Flexion ◽  
Three Dimensional ◽  
Axial Loading ◽  
Mechanical Tests ◽  
Ligament Injury ◽  
Anterior Talofibular Ligament ◽  
Ankle Ligaments ◽  
Lateral Ankle Ligaments

The present study aims to clarify the influence of the interosseous talocalcaneal ligament (ITCL) injury associated with injury to the lateral ankle ligaments on the ankle-subtalar joint complex motion under conditions of physiologic loading. We conducted mechanical tests using five fresh cadaveric lower extremities. Each specimen was mounted in the loading device and an axial cyclic load from 9.8 to 686 N was applied. Three-dimensional rotations of the ankle and the subtalar joint were measured simultaneously by a linkage electric goniometer. Mechanical tests were repeated after sectioning of the anterior talofibular ligament (ATFL), and again after additional sectioning of the ITCL. In the intact condition, the ankle and the subtalar joints rotated consistently with increase of the load. The predominant rotations were plantar flexion and adduction at the ankle joint, with some eversion demonstrated at the subtalar joint. Although ATFL sectioning did not significantly change the motion of the two joints, additional sectioning of the ITCL significantly increased adduction and total rotation of the ankle joint. The present study demonstrated that a combined injury of the ATFL and the ITCL can induce anterolateral rotatory instability of the ankle joint under conditions of axial loading.

The Effect of Damage to the Lateral Collateral Ligaments on the Mechanical Characteristics of the Ankle Joint—An In-Vitro Study

1990 ◽  
Vol 112 (2) ◽  
pp. 129-137 ◽  
Author(s):  
S. Siegler ◽  
Jie Chen ◽  
C. D. Schneck
Keyword(s):  
Ankle Joint ◽  
Diagnostic Procedure ◽  
Mechanical Characteristics ◽  
Three Dimensional ◽  
Lower Limbs ◽  
Anterior Talofibular Ligament ◽  
Collateral Ligaments ◽  
Ligament Injuries ◽  
Calcaneofibular Ligament ◽  
Lateral Collateral Ligaments

Injuries to the lateral collateral ligaments of the ankle joint are among the most frequently occurring injuries at the lower limb. The present study was conducted for the purpose of establishing the basis for the development of a quantitative diagnostic procedure for such injuries. To achieve this goal, the effect of four types of ligament injuries on the three-dimensional mechanical characteristics of the ankle were investigated. These types of injuries consisted of: 1) isolated tear of the anterior talofibular ligament; 2) isolated tear of the calcaneofibular ligament; 3) isolated tear of the posterior talofibular ligament; and 4) combined tear of both the anterior talofibular ligament and the calcaneofibular ligament. The experiments were conducted on 31 amputated lower limbs and consisted of comparing the three-dimensional load-displacement and flexibility characteristics of the ankle joint prior to and following sectioning of selected ligaments. The experimental and analytical procedures used to derive these characteristics was developed previously by the authors [3, 24]. From the results of this study it was concluded that the three-dimensional flexibility characteristics of the ankle joint are strongly influenced by damage to the lateral collateral ligaments. Furthermore, it was found that each type of ligament injury produced unique and identifiably changes in the flexibility characteristics of the ankle. These unique changes, which are described in detail in this paper, can be used to discriminate between the different types of ligament injuries. Consequently, it was concluded that it is feasible to develop a quantitative diagnostic procedure for ankle ligament injuries based on the effect of the injury on the flexibility characteristics of the ankle.

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