Studders, Carson

Project title: Effect of Screw Configuration on Bone Graft Micromotion in BIO-RSA

Department: Mechanical Engineering

Faculty supervisor: Dr. Joshua Giles

"Reverse shoulder arthroplasty (RSA) is a joint replacement procedure wherein the normal anatomical ball-and-socket relationship between the humerus (arm bone) and scapula (shoulder blade) is reversed by placing a cup-shaped implant on the humerus and a ball-shaped implant on the scapula. Severe deformity of the bone into which the scapular implant is anchored makes this procedure more difficult and increases the risk of early loosening and other unfavourable outcomes, but a new procedure called BIO-RSA (bony increased offset RSA) seeks to decrease these risks by reconstructing this area with a bone graft. While this increases the range of applicability of the procedure, the mechanical behaviour of the bone graft when subjected to joint forces during normal arm motion is not well studied. Above a certain threshold of relative motion at the graft-implant and graft-bone interfaces the graft will not successfully integrate, increasing the risk of loosening and the need for revision surgery. To investigate what impact implant screw configuration, the primary fixation method, has on graft relative motion, the results of computational finite element models done as part of this research will be experimentally validated with a custom testing device and instrumented samples."