Is MIO-RSA Noninferior to BIO-RSA When it Comes to Mechanical Implant Stability?

Lateralization of reverse shoulder arthroplasties may reduce the risk for complications such as limited range of motion (ROM), and scapular notching, where the lower part of the scapular neck becomes eroded due to impingement against the humeral component. There's several ways to lateralize the glenoid component, a bone transplant placed underneath the glenoid component (Bony Increased Offset Reversed Shoulder Arthroplasty: BIO-RSA) has been used for some time. Recently glenoid components with metallic lateralization of the joint centre (Metal-Increased Offset Reversed Shoulder Arthroplasty: MIO-RSA) have been introduced, but there is not much comparative literature on metal vs. bony lateralization. Patients with osteoarthritis and medialization of the glenoid articular surface, who willing to participate in a study will be randomized to receive either MIO-RSA or a BIO-RSA. CT-based motion analysis (CTMA) will be used to measure the 3-dimensional migration pattern of the glenoid components to assess the stability of the prostheses up to two years after implantation.