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Effect of Biceps Reattachment Location on Moment Arm

Weir, David Michael (2010) Effect of Biceps Reattachment Location on Moment Arm. Master's Thesis, University of Pittsburgh. (Unpublished)

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The ultimate goal of the project is to quantify the effect of biceps tendon attachment location in clinically relevant terms, range of motion and torque generating ability as measured by muscle moment arm. Our hypothesis was that an anatomic repair would recreate native tendon moment arm and forearm rotation, while a non-anatomic insertion would compromise moment arm and forearm rotation. Isometric supination torque and range of motion were measured for the native distal biceps tendon and 4 systematically placed repair points in 6 cadaveric specimens. A computer controlled elbow simulator, which exerts known loads on the forearm applied through the biceps tendon, was adapted to a device capable of measuring isometric forearm torque generated by cadaveric elbows.For torque testing, the biceps tendon was loaded, and the torque generated was measured with the forearm fixed at 60° pronation, neutral, and 60° supination. Range of motion testing was done by incrementally loading the biceps while measuring the supination motion generated using a digital goniometer.Tendon location and forearm position significantly affected the moment arm of the biceps. The native tendon had a mean moment arm of 5.67±2.86 and 10.44±1.45 (mm) in 60° supination and neutral respectively. Anatomic repair in all forearm positions showed no significant difference from the native insertion. However, a centralized anterior repair was significantly lower in supination (0.15 ±3.48) and neutral (7.65 ±1.95) and also produced significantly less supination motion. No difference was observed between all tendon locations in pronation. Clinically, these findings would suggest that patients with a biceps repair might experience the most weakness in a supinated position without experiencing a deficit in the pronated forearm. Surgically, particular attention needs to be paid to the geometry of the tuberosity and location of tendon reattachment as it could play a critical role in maximizing the functional outcomes of patients. The results of this study could help surgeons gain a better understanding of how to optimize their repair and thereby improve the expected outcome of their patients with distal biceps injuries.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Weir, David Michaeldmw18@pitt.eduDMW18
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee MemberMiller, Mark
Committee MemberSmolinski, Patrickpatsmol@pitt.eduPATSMOL
Committee MemberClark, William Wwclark@pitt.eduWCLARK
Date: 25 June 2010
Date Type: Completion
Defense Date: 30 March 2010
Approval Date: 25 June 2010
Submission Date: 1 April 2010
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Mechanical Engineering
Degree: MSME - Master of Science in Mechanical Engineering
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: Biceps Rupture; Distal Biceps Tendon; Supination Moment Arm
Other ID:, etd-04012010-112757
Date Deposited: 10 Nov 2011 19:33
Last Modified: 15 Nov 2016 13:38


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