A Method for Predicting Collagen Fiber Alignment in the Glenohumeral Capsule During Clinically Relevant Deformations

2012 ◽  
Author(s):  
Carrie A. Rainis ◽  
Rouzbeh Amini ◽  
Richard E. Debski
Keyword(s):  
Collagen Fiber ◽  
Soft Tissues ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Complex Loading ◽  
Anterior Dislocation ◽  
Fiber Alignment ◽  
Glenohumeral Ligament ◽  
Glenohumeral Capsule ◽  
Collagen Fiber Alignment

Injury to the anteroinferior (anterior band of the inferior glenohumeral ligament (AB-IGHL) and axillary pouch) glenohumeral capsule is a common result of anterior dislocation [1]. Validated finite element models of the capsule can be used to address research questions regarding diagnostic and repair techniques targeted to this region of the capsule. However, these models require adequate constitutive models to describe capsule behavior. Structural models have improved predictions of capsule behavior compared to phenomenological models [2] but current experimental techniques used to measure fiber distributions in biologic soft tissues require that the sample be planar and cannot be performed on three-dimensional structures. Although recent work has demonstrated that the fiber kinematics in the capsule do not precisely follow the global tissue deformation [3], the affine assumption is presently the best approximation to provide initial insight into changes in collagen fiber alignment under moderate deformations. The collagen fibers in localized areas of planar samples from the anteroinferior capsule align with the direction of loading [4,5]; however, their behavior may be quite different during the complex loading conditions experienced by the intact capsule. Therefore, the objective of this work was to computationally project planar fiber distribution information to the three-dimensional glenohumeral capsule and use the affine assumption to quantify the change in fiber alignment of the anteroinferior glenohumeral capsule from an inflated reference state to three clinically relevant joint positions.

Collagen Fiber Alignment and Maximum Principal Strain in the Glenohumeral Capsule Predict Location of Failure During Uniaxial Extension

2011 ◽  
Author(s):  
Kelvin Luu ◽  
Carrie A. Voycheck ◽  
Patrick J. McMahon ◽  
Richard E. Debski
Keyword(s):  
Collagen Fiber ◽  
Glenohumeral Joint ◽  
Uniaxial Extension ◽  
Principal Strain ◽  
Fiber Alignment ◽  
Glenohumeral Ligament ◽  
Maximum Principal Strain ◽  
Inferior Glenohumeral Ligament ◽  
Glenohumeral Capsule ◽  
Collagen Fiber Alignment

The glenohumeral joint is frequently dislocated causing injury to the glenohumeral capsule (axillary pouch (AP), anterior band of the inferior glenohumeral ligament (AB-IGHL), posterior band of the inferior glenohumeral ligament (PB-IGHL), posterior (Post), and anterosuperior region (AS)). [1, 2] The capsule is a passive stabilizer to the glenohumeral joint and primarily functions to resist dislocation during extreme ranges of motion. [3] When unloaded, the capsule consists of randomly oriented collagen fibers, which play a pertinent role in its function to resist loading in multiple directions. [4] The location of failure in only the axillary pouch has been shown to correspond with the highest degree of collagen fiber orientation and maximum principle strain just prior to failure. [4, 5] However, several discrepancies were found when comparing the collagen fiber alignment between the AB-IGHL, AP, and PB-IGHL. [3,6,7] Therefore, the objective was to determine the collagen fiber alignment and maximum principal strain in five regions of the capsule during uniaxial extension to failure and to determine if these parameters could predict the location of tissue failure. Since the capsule functions as a continuous sheet, we hypothesized that maximum principal strain and peak collagen fiber alignment would correspond with the location of tissue failure in all regions of the glenohumeral capsule.

Collagen Fiber Alignment and Maximum Principle Strain in the Axillary Pouch Predict Location of Failure During Uniaxial Extension

2010 ◽  
Author(s):  
Carrie A. Voycheck ◽  
Patrick J. McMahon ◽  
Richard E. Debski
Keyword(s):  
Maximum Principle ◽  
Collagen Fiber ◽  
Glenohumeral Joint ◽  
External Rotation ◽  
Uniaxial Extension ◽  
Supraspinatus Tendon ◽  
Collagen Fibers ◽  
Fiber Alignment ◽  
Glenohumeral Ligament ◽  
Collagen Fiber Alignment

The glenohumeral joint is frequently dislocated in the anterior direction causing injury to the anteroinferior (axillary pouch, anterior band of the inferior glenohumeral ligament (AB-IGHL)) capsule. [1, 2] When unloaded, the axillary pouch consists of randomly oriented collagen fibers. These fibers play a pertinent role in its function to resist loading in multiple directions during dislocation at the extreme ranges of motion. [3] Maximum principle strain directions in the anteroinferior capsule have been shown to align with the AB-IGHL during increasing external rotation, suggesting that the collagen fibers may become more aligned with loading as well. [4] In addition, at positions of increased external rotation, the peak maximum principle strains in the capsule correspond to the location of a common capsular failure known as the Bankart lesion. [4] Further, an increase in collagen fiber alignment with load in the supraspinatus tendon has been shown in the toe region of the load-elongation curve. [5] Therefore, it was hypothesized that increases in the collagen fiber alignment and maximum principle strain would correlate with the location of tissue failure. The objective of this work was to determine the collagen fiber alignment and maximum principle strain in the axillary pouch during uniaxial extension to failure and to determine if these parameters could predict the location of tissue failure.

Initial Collagen Fiber Alignment Determines the Mechanical and Structural Response of Cell-Compacted Tissue-Equivalents Under Indentation

2011 ◽  
Author(s):  
Spencer P. Lake ◽  
Victor H. Barocas
Keyword(s):  
Collagen Fiber ◽  
Soft Tissues ◽  
Model System ◽  
Type I ◽  
Collagen Network ◽  
Fiber Alignment ◽  
Collagen Organization ◽  
Tissue Equivalents ◽  
Collagen Fiber Alignment ◽  
Indentation Site

The mechanical behavior of connective soft tissues depends largely on their structural organization, particularly of the collagen network. Previous studies have utilized polarized light imaging techniques to quantify collagen organization and fiber kinematics under tensile load (e.g., [1–2]). Many native tissues function in non-tensile loading environments, however, and the microstructural response to such loads is poorly understood. For example, fiber-reinforced soft tissues can be subjected to indentation in vivo (e.g., supraspinatus tendon in shoulder, flexor tendons that wrap around bones), resulting in a complex combination of compressive (near indentation site) and tensile forces (away from indentation site) being applied to the tissue. In order to understand and predict a tissue’s response to such loading, the respective roles of the collagen and non-fibrillar matrix must be elucidated. In particular, how do the properties of the collagen network (e.g., density/organization) and non-fibrillar matrix (e.g., type/quantity) modulate behavior under load? In order to address these questions, our group has utilized type I collagen gel tissue-equivalents (TEs) as a simplified model system to evaluate properties and relationships of tissue components. TEs are particularly useful because organizational and compositional properties can be controlled during formulation (e.g., mold geometry altered to induce changes in collagen fiber alignment [3]). While our other work has used co-gel tissue analogs to evaluate the contribution of non-fibrillar matrix to indentation [4], the purpose of this study was to evaluate the role of initial collagen organization on tissue behavior in indentation using cell-compacted TEs as a model system.

scholarly journals Quantitative mapping of collagen fiber alignment in thick tissue samples using transmission polarized-light microscopy

2016 ◽  
Vol 21 (7) ◽  
pp. 071111 ◽  
Author(s):  
Dmitry D. Yakovlev ◽  
Marina E. Shvachkina ◽  
Maria M. Sherman ◽  
Andrey V. Spivak ◽  
Alexander B. Pravdin ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Collagen Fiber ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
Tissue Samples ◽  
Fiber Alignment ◽  
Quantitative Mapping ◽  
Collagen Fiber Alignment

Effect of Preconditioning on Collagen Fiber Recruitment: Inhomogeneous Properties of Rat Supraspinatus Tendon

2010 ◽  
Author(s):  
Kristin S. Miller ◽  
Lena Edelstein ◽  
Louis J. Soslowsky
Keyword(s):  
Mechanical Properties ◽  
Collagen Fiber ◽  
Insertion Site ◽  
Supraspinatus Tendon ◽  
Fiber Alignment ◽  
Rigorous Evaluation ◽  
Structural Alterations ◽  
Testing Protocol ◽  
Inhomogeneous Properties ◽  
Collagen Fiber Alignment

Cyclic preconditioning is a commonly accepted initial component of any tendon testing protocol. Preconditioning provides tendons with a consistent “history” and stress-strain results become repeatable allowing for rigorous evaluation and comparison. While it is widely accepted that preconditioning is important, changes that occur during preconditioning are not well understood. Micro-structural alterations, such as re-arrangement of collagen fibers, is one proposed mechanism of preconditioning [1,4]. However, this mechanism has not been examined. Therefore, the objective of this study is to locally measure: 1) fiber re-alignment during preconditioning, stress relaxation and tensile testing and 2) corresponding mechanical properties, to address mechanisms of preconditioning as well as tissue nonlinearity and inhomogeneity in the rat supraspinatus tendon. We hypothesize that 1) fiber re-alignment will be greatest in the toe region, but will also occur during preconditioning and 2) mechanical properties and initial collagen fiber alignment will be greater in the midsubstance location of the tendon compared to the tendon-to-bone insertion site.

Collagen Fiber Re-Alignment and Mechanical Properties in a Mouse Supraspinatus Tendon Model: Examining Changes With Age and Location

2012 ◽  
Author(s):  
Kristin S. Miller ◽  
Brianne K. Connizzo ◽  
Elizabeth Feeney ◽  
Louis J. Soslowsky
Keyword(s):  
Mechanical Properties ◽  
Collagen Fiber ◽  
Mechanical Load ◽  
Mechanical Test ◽  
Insertion Site ◽  
Supraspinatus Tendon ◽  
Tissue Response ◽  
Mechanical Stimuli ◽  
Fiber Alignment ◽  
Collagen Fiber Alignment

One postulated mechanism of tendon structural response to mechanical load is collagen fiber re-alignment. Recently, where collagen fiber re-alignment occurs during a tensile mechanical test has been shown to vary by tendon age and location in a postnatal developmental mouse supraspinatus tendon (SST) model [1]. It is thought that as the tendon matures and its collagen fibril network, collagen cross-links and collagen-matrix interactions develop, its ability to respond quickly to mechanical stimuli hastens [1]. Additionally, the insertion site and midsubstance of postnatal SST may develop differently and at different rates, providing a potential explanation for differences in fiber re-alignment behaviors at the insertion site and midsubstance at postnatal developmental time points [1]. However, collagen fiber re-alignment behavior, in response to mechanical load at a mature age and in comparison to developmental ages, have not been examined. Therefore, the objectives of this study are to locally measure: 1) fiber re-alignment during preconditioning and tensile mechanical testing and 2) to compare local differences in collagen fiber alignment and corresponding mechanical properties to address tissue response to mechanical load in the mature and postnatal developmental mouse SST. We hypothesize that 1) 90 day tendons will demonstrate the largest shift in fiber re-alignment during preconditioning, but will also re-align during the toe- and linear-regions. Additionally, we hypothesize that 2) mechanical properties and initial collagen fiber alignment will be greater in the midsubstance of the tendon compared to the tendon-to-bone insertion site at 90 days, 3) that mechanical properties will increase with age, and that 4) collagen fiber organization at the insertion site will decrease with age.

Performing Clinical Exams at Specific Joint Positions May Help Identify Injured Regions of the Glenohumeral Capsule Following Anterior Dislocation

2012 ◽  
Author(s):  
Carrie A. Rainis ◽  
Daniel P. Browe ◽  
Patrick J. McMahon ◽  
Richard E. Debski
Keyword(s):  
Tissue Damage ◽  
External Rotation ◽  
Anterior Dislocation ◽  
Joint Position ◽  
Anterior Instability ◽  
Glenohumeral Ligament ◽  
Before And After ◽  
Inferior Glenohumeral Ligament ◽  
Glenohumeral Capsule ◽  
The Relationship

The anteroinferior glenohumeral capsule (anterior band of the inferior glenohumeral ligament (AB-IGHL), axillary pouch) limits anterior translation, particularly in positions of external rotation. [1, 2] Permanent tissue deformation that occurs as a result of dislocation contributes to anterior instability, but, the extent and effects of this injury are difficult to evaluate as the deformation cannot be seen using diagnostic imaging. Clinical exams are used to identify the appropriate location of tissue damage and current arthroscopic procedures allow for selective tightening of localized capsule regions; however, identifying the specific location for optimal treatment of each patient is challenging. Although the reliability of clinical exams has been shown to change with joint position [3] a standardized procedure has yet to be established. This lack of standardization is particularly problematic since capsule function is highly dependent upon joint position [4–7], and could be responsible for failed repairs attributed to plication of the wrong capsular region [8]. Understanding the relationship between the location of tissue damage and changes in capsule function following anterior dislocation could aid clinicians in diagnosing and treating anterior instability. Therefore, the objective of this work was to compare strain distributions in the anteroinferior capsule before and after anterior dislocation in order to identify joint positions at which clinical exams would be capable of detecting damage (nonrecoverable strain) in specific locations.

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