Jordan, David
(2019)
The Correlation of Force to Deformation of the Medial Ulnar Collateral Ligament (mUCL) With Consideration of Band Laxity.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Overhand throwing performed at a competitive level generates extreme loading conditions at the elbow. The reaction loads that arise as a result of these conditions are supported by the biological structures within the elbow. One such structure is the medial ulnar collateral ligament (mUCL). In order to predict potential injuries, a thorough understanding of the ligament’s response to such loads is required.
Previous works have shown the mUCL considered as two distinct portions, anterior and posterior, both of which possess different geometric and physical attributes [1]. In this study, the ligament is considered as being composed of three distinct portions. These are the anterior, middle and posterior bands. It is the combination of the responses of these bands that combine, through the principle of superposition, to form the response of the overall mUCL. In this work, the overall load-bearing response of the mUCL is determined by sequentially superposing each band as the laxity within each band is relieved upon loading. Determining the amount of laxity in each band provides the initial load-bearing length for the bands, necessary for strain calculation.
Seven cadaveric elbow specimens were used for the study. The intact mUCL of each specimen was tested under vertical distraction and then subsequently retested after two separate transections. The tests were performed within an MTS loading machine at four different flexion angles. The average slack in each band was found to be non-zero and flexion dependent. The posterior and anterior bands were the most lax at full extension and full flexion, with an average slack of 2.7 mm and 2.2 mm respectively.
Individual band force-strain characteristics showed the anterior band to be the stiffest at the lesser flexion angles, with the middle band becoming the stiffest at the higher flexion angles. Overall mUCL force-strain profiles showed the ligament to be stiffest at 60° of flexion, with approximately 190N of force required for 2% elongation.
The presence of the laxity and the prominence of the mechanical responses of the individual bands, show the need for consideration of such factors when aiming to accurately portray the mechanical response of the mUCL.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
24 January 2019 |
| Date Type: |
Publication |
| Defense Date: |
15 August 2018 |
| Approval Date: |
24 January 2019 |
| Submission Date: |
4 September 2018 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
88 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Elbow, Medial Ulnar Collateral Ligament, Slack Length, Laxity, Superposition, Baseball Pitching, Force, Strain, Ligament Bands |
| Date Deposited: |
24 Jan 2019 17:13 |
| Last Modified: |
24 Jan 2019 17:13 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/35302 |
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