Thesis
A system for mechanically testing in-situ clavicular fracture fixation devices
Master of Science (M.S.), Drexel University
Sep 2015
DOI:
https://doi.org/10.17918/etd-6699
Abstract
Clavicular fractures account for 35% of all shoulder injuries. These fractures are prone to mal-alignment and conservative treatment of these mal-aligned fractures has been shown to be a key contributing factor in decreased shoulder function. Although surgical correction methods have been developed, it is still unknown what degree of mal-alignment requires surgical intervention. The purpose of this study was to develop and test an in-situ clavicular fracture mal-alignment device to be used in a cadaveric shoulder kinematic study. Ultimately this cadaveric study would provide guidance to orthopaedic surgeons on when conservative treatment is appropriate, and when surgical intervention is needed. In order to test the performance of this device, an ex-vivo mechanical testing platform was developed. The platform was based on a cantilever beam concept where: turkey-tibia bones were used as a model of the human clavicle, kinematic markers (Polhemus motion capture system) measured displacement along the bone's length, a load cell (OptoForce) was placed on the free end to record the force applied, and the mal-alignment device was fixed to the bone and spanned the fracture site. The platform was then used to conduct several experiments on bone before and after fracture/fixation which examined the effect of: a) specimen variability, b) loading direction, c) device material and d) device fixation to bone, on displacement of the distal bone. Maximum displacements were found to be different for the various intact bones, thus all fractured/fixed displacement data were measured relative to intact data for each specimen. In addition, maximum displacements of the fractured/fixed bone were found to vary according to loading direction, thus displacement data for each loading direction were compared separately. Using this approach, the plastic mal-alignment device was found to have dramatically larger displacements (43.68mm) than the aluminum device (1.51mm). In addition, mechanical fixation was found to have larger displacements (9.19mm) than both mechanical/glue (0.72mm) as well as all glue fixation (1.51mm). Ultimately, the testing system was successful at measuring increases in displacements of fractured/fixed bone relative to intact, and as such is an ideal platform for future mal-alignment device testing. With respect to the mal-alignment device, the testing clearly indicated that aluminum material must be used and that proper fixation of the device to the bone needs improvement. Future work can now use this platform to improve the mal-alignment device such that it can be used in a cadaver study to examine the effect of mal-alignment on shoulder kinematics.
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Details
- Title
- A system for mechanically testing in-situ clavicular fracture fixation devices
- Creators
- Rebecca Lynn Wright - DU
- Contributors
- Joseph J. Sarver (Advisor) - Drexel University (1970-)Duane David Ebaugh (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- viii, 33 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems (1997-2026); Drexel University
- Other Identifier
- 6699; 991014632231204721