The Effects of Refreezing on the Tensile Properties of the Medial Collateral Ligament-Bone Complex: A Rabbit Model

2003 ◽  
Author(s):  
Daniel K. Moon ◽  
Mary T. Gabriel ◽  
Steven D. Abramowitch ◽  
Yoshiyuki Takakura ◽  
Savio L.-Y. Woo
Keyword(s):  
Stress Relaxation ◽  
Tensile Properties ◽  
Medial Collateral Ligament ◽  
Soft Tissues ◽  
Rabbit Model ◽  
Frozen Storage ◽  
Cyclic Stress ◽  
Specimen Preparation ◽  
Freezing And Thawing ◽  
Collateral Ligament

Biomechanical tests of soft tissues, especially those from human cadavers, are generally done after a period of postmortem storage by freezing. In some instances, specimen preparation and testing can be complex and can take place over several days, thus necessitating an additional period of frozen storage before biomechanical evaluation is completed. Studies have been done in the past, which investigated the effects of postmortem freezing on the tensile properties of ligament-bone complexes (Viidik and Lewin 1966; Noyes and Grood 1976; Dorlot 1980; Barad 1982; Nikolaou 1986; Woo, Orlando et al. 1986). It has been shown in our laboratory that careful postmortem freezing for up to three months did not significantly change the mechanical properties of the ligament midsubstance and the cyclic stress relaxation behavior and the structural properties of the ligament-bone complex, but the area of hysteresis was significantly reduced in the stored specimens for the first few cycles of cyclic stress relaxation (Woo, Orlando et al. 1986). Hence, it is important to ensure that an additional freezing and thawing cycle will not further change the tensile properties of these tissues. Therefore, the objective of this study was to evaluate the effects of freezing and thawing twice at 20°C on the structural and viscoelastic properties of femur-medial collateral ligament-tibia complex (FMTC) in a rabbit model.

An Experimental and Analytical Evaluation of the Nonlinear Viscoelastic Properties of the Healing Medial Collateral Ligament in a Goat Model

2003 ◽  
Author(s):  
S. D. Abramowitch ◽  
T. D. Clineff ◽  
R. E. Debski ◽  
S. L.-Y. Woo
Keyword(s):  
Stress Relaxation ◽  
Medial Collateral Ligament ◽  
Viscoelastic Properties ◽  
Soft Tissues ◽  
Viscoelastic Behavior ◽  
Collateral Ligament ◽  
Relaxation Experiment ◽  
Nonlinear Viscoelastic ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic

The medial collateral ligament (MCL) is one of the most frequently injured ligaments in the knee. Although it can heal spontaneously after rupture, laboratory studies have shown that the mechanical properties of the healing MCL remain inferior to normal for up to two years after injury (1). Additionally, the healing MCL has been shown to display increased amounts of stress relaxation and creep (2). In order to more completely describe the viscoelastic properties of healing ligaments, we propose to use the Quasi-Linear Viscoelastic (QLV) theory formulated by Fung (1972). This theory has been used to successfully describe the viscoelastic properties of many soft-tissues (3). Recently, our research center has developed an improved approach to determine the constants describing the QLV theory based on data collected from a stress relaxation experiment that utilizes a slow strain rate during loading. This approach allows for experimental errors that commonly result from fast strain rates to be avoided (ex. overshoot) (4). Therefore, the objective of this study were to use this new approach to determine the constants describing the quasi-linear viscoelastic behavior of the healing goat MCL at 12 weeks after injury.

The Time and History-Dependent Viscoelastic Properties of the Canine Medial Collateral Ligament

1981 ◽  
Vol 103 (4) ◽  
pp. 293-298 ◽  
Author(s):  
S. L.-Y. Woo ◽  
M. A. Gomez ◽  
W. H. Akeson
Keyword(s):  
Medial Collateral Ligament ◽  
Viscoelastic Properties ◽  
Cyclic Stress ◽  
Elastic Response ◽  
Collateral Ligament ◽  
Stress Strain ◽  
Linear Viscoelastic ◽  
Viscoelastic Theory ◽  
Linear Viscoelastic Theory

The viscoelastic properties of the canine medial collateral ligament (MCL) were investigated. Stress-strain relationships at different strain rates, long-term stress relaxation and cyclic stress-strain curves of the MCL were obtained experimentally using a bone-MCL-bone preparation. The experimental data were used in conjunction with the quasi-linear viscoelastic theory as proposed by Fung [15] to characterize the reduced relaxation function, G(t) and elastic response σe (ε) of this tissue. It was found that the quasi-linear viscoelastic theory can adequately describe the time and history-dependent rheological properties of the canine medial collateral ligament.

An Improved Method to Analyze the Stress Relaxation of Ligaments Following a Finite Ramp Time Based on the Quasi-Linear Viscoelastic Theory

2004 ◽  
Vol 126 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Steven D. Abramowitch ◽  
Savio L.-Y. Woo
Keyword(s):  
Stress Relaxation ◽  
Soft Tissues ◽  
Viscoelastic Behavior ◽  
Cyclic Stress ◽  
Elastic Response ◽  
Curve Fit ◽  
Order Of Magnitude ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Theory ◽  
Experimental Values

The quasi-linear viscoelastic (QLV) theory proposed by Fung (1972) has been frequently used to model the nonlinear time- and history-dependent viscoelastic behavior of many soft tissues. It is common to use five constants to describe the instantaneous elastic response (constants A and B) and reduced relaxation function (constants C, τ1, and τ2) on experiments with finite ramp times followed by stress relaxation to equilibrium. However, a limitation is that the theory is based on a step change in strain which is not possible to perform experimentally. Accounting for this limitation may result in regression algorithms that converge poorly and yield nonunique solutions with highly variable constants, especially for long ramp times (Kwan et al. 1993). The goal of the present study was to introduce an improved approach to obtain the constants for QLV theory that converges to a unique solution with minimal variability. Six goat femur-medial collateral ligament-tibia complexes were subjected to a uniaxial tension test (ramp time of 18.4 s) followed by one hour of stress relaxation. The convoluted QLV constitutive equation was simultaneously curve-fit to the ramping and relaxation portions of the data r2>0.99. Confidence intervals of the constants were generated from a bootstrapping analysis and revealed that constants were distributed within 1% of their median values. For validation, the determined constants were used to predict peak stresses from a separate cyclic stress relaxation test with averaged errors across all specimens measuring less than 6.3±6.0% of the experimental values. For comparison, an analysis that assumed an instantaneous ramp time was also performed and the constants obtained for the two approaches were compared. Significant differences were observed for constants B, C, τ1, and τ2, with τ1 differing by an order of magnitude. By taking into account the ramping phase of the experiment, the approach allows for viscoelastic properties to be determined independent of the strain rate applied. Thus, the results obtained from different laboratories and from different tissues may be compared.

Medial collateral ligament replacement in the rabbit model: A preliminary report

1975 ◽  
Vol 3 (6) ◽  
pp. 271-276 ◽  
Author(s):  
William C. McMaster ◽  
Sharon Liddle ◽  
Sanford H. Anzel ◽  
Theodore R. Waugh
Keyword(s):  
Medial Collateral Ligament ◽  
Preliminary Report ◽  
Rabbit Model ◽  
Collateral Ligament ◽  
Ligament Replacement

EFFECTS OF DIABETES AND EXERCISE ON SOFT CONNECTIVE TISSUE PROPERTIES AT THE KNEE IN THE RAT

2009 ◽  
Vol 12 (02) ◽  
pp. 95-104
Author(s):  
Kenneth J. Fischer ◽  
Elizabeth A. Novak ◽  
Irina V. Smirnova ◽  
G. Kesava Reddy ◽  
Lisa Stehno-Bittel
Keyword(s):  
Stress Relaxation ◽  
Connective Tissue ◽  
Knee Joint ◽  
Medial Collateral Ligament ◽  
Joint Stiffness ◽  
Joint Capsule ◽  
Diabetic Group ◽  
Type I ◽  
Collateral Ligament ◽  
Posterior Tibial

The primary diabetes-related health concerns are neuropathy and cardiovascular changes. Connective tissue changes can also affect quality of life by increasing ligament and joint capsule stiffness, impairing proprioception, limiting function, and leading to greater risk of falling. Our objectives were to evaluate effects of Type I diabetes and exercise on medial collateral ligament properties and overall knee-joint stiffness and stress relaxation. Thirty-four male Sprague–Dawley rats, approximately two months old, were divided into three groups—sedentary controls (n=10), sedentary diabetics (n=10) and exercised diabetics (n=14). Diabetes was induced by streptozotocin injection. Exercised rats ran 5 days/week, 1 hr/day, at 20 m/min. All animals were sacrificed seven weeks after induction of diabetes. Stiffness and stress relaxation of the whole knee joint was tested in distraction and anterior–posterior tibial displacement. The joint capsule and knee ligaments were then sectioned, preserving the medial collateral ligament (MCL). The MCL structural properties were tested by knee distraction at a flexion angle of 40°. Whole joint stiffness was 23% higher for anterior tibial displacement in the exercised diabetic group, and 31% higher for posterior tibial displacement, compared to controls. Whole joint stress relaxation in distraction was 25% lower for the exercised diabetic group. No differences were found for MCL properties. Diabetes and exercise clearly increased joint stiffness. The effects may be due to tissue adaptation, but appear more likely to be due to increased blood flow that promotes increased tissue glycation in the joint capsule.

A Cyclooxygenase-2 Inhibitor Impairs Ligament Healing in the Rat

2001 ◽  
Vol 29 (6) ◽  
pp. 801-805 ◽  
Author(s):  
Christopher L. Elder ◽  
Laurence E. Dahners ◽  
Paul S. Weinhold
Keyword(s):  
Medial Collateral Ligament ◽  
Soft Tissues ◽  
Nonsteroidal Antiinflammatory Drugs ◽  
Cyclooxygenase 2 ◽  
Ligament Injuries ◽  
Collateral Ligament ◽  
Antiinflammatory Drugs ◽  
Increased Risk ◽  
Ligament Healing ◽  
Specific Inhibitors

Celecoxib was the first of a new class of nonsteroidal antiinflammatory drugs, the cyclooxygenase-2 (COX-2) specific inhibitors, marketed as having the same antiinflammatory efficacy as other nonsteroidal antiinflammatory drugs without their increased risk of gastrointestinal ulceration. Among the widest uses of nonsteroidal antiinflammatory drugs is in the treatment of acute soft tissue injuries. Although the benefits of celecoxib have been shown when used for rheumatoid arthritis and osteoarthritis, we are unaware of any studies concerning its effect on soft tissues. We used the surgically incised medial collateral ligament of male Sprague-Dawley rats as an experimental model for acute ligament injuries to investigate the effects of celecoxib on ligament healing. Fifty rats underwent surgical transection of the right medial collateral ligament. Postoperatively, half were given celecoxib for the first 6 days of recovery, the other half were not. The animals were sacrificed 14 days after the operation, and both the injured and uninjured medial collateral ligaments were mechanically tested to failure in tension. Celecoxib-treated/injured ligaments were found to have a 32% lower load to failure than untreated/ injured ligaments. The results of this study do not support use of cyclooxygenase-2 specific inhibitors in the treatment of ligament injuries.

Hyperbaric oxygen therapy improves medial collateral ligament healing in a rabbit model

2011 ◽  
Vol 2 (1) ◽  
pp. 7-11
Author(s):  
Steve Wen-Neng Ueng ◽  
Mel Shiuann-Sheng Lee ◽  
Ching-Lung Tai ◽  
Kuo-Yao Hsu ◽  
Song-Shu Lin ◽  
...  
Keyword(s):  
Hyperbaric Oxygen ◽  
Medial Collateral Ligament ◽  
Hyperbaric Oxygen Therapy ◽  
Oxygen Therapy ◽  
Rabbit Model ◽  
Collateral Ligament ◽  
Ligament Healing
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