UMASS Medical School
Rigid sternal fixation uses cortical-screw/plate systems; however, the sternum is predominately cancellous bone. We hypothesized cancellous screws would provide better fixation in screw pullout and cyclic fatigue tests. Maximum pullout forces showed mean forces for cancellous screws were significantly higher ( 67.217710.23N) than for cortical (28.917711.74N). After 25,000 cycles, the cancellous system reached 1.16mm distraction, the cortical-screw/ plate system reached 1.55mm. These results indicate the superior performance of cancellous screws over cortical. Further research is needed to confirm trends.
Worcester Polytechnic Institute
Major Qualifying Project
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