Date of Award


Document Type


Degree Name

Master of Science (MS)



Committee Chair/Advisor

John D. DesJardins

Committee Member

Jiro Nagatomi

Committee Member

Reed Gurchiek


Reverse total shoulder arthroplasty (RTSA) is a procedure that aims to fix irreversible rotator cuff damage and degenerative glenohumeral joint diseases that hinder arm abduction. One major complication of RTSA is glenoid baseplate failure resulting from increased movement at the bone-baseplate interface. This study examined 36, 12 PCF composite Sawbones® scapulae. The specimens were split equally into 6 study groups, each having different implant configurations with varying baseplate lateralization and central screws or posts. Each specimen was subjected to cyclic shear loading and failure testing on an Instron to determine implant micromotion and load values.

After testing, ANOVA tests were run at a 95% confidence interval. At 150 microns of movement, no groups were statistically significant from each other with a cumulative p-value of 0.3908. At implant failure, group 5 and group 1 were statistically significant. Group 5 had a p-value of 0.0049 with an average load of 1301.08 N. Group 1 had a p-value of 0.0133 with an average load of 1267.13 N. From the results at 150 microns of movement, all 6 study groups will perform the same under typical shoulder usage without major implant movement. At implant failure, the study results prove that post and screw constructs that have 4 mm lateralized glenospheres achieve the best bone-baseplate interface and can withstand the highest forces. Limitations of the study include small variations in implant alignment angles and the Sawbones® model not being of clinical relevance due to a lack of anatomical components.

Available for download on Saturday, May 31, 2025