Description

Many studies have showed pain relief and improvement in shoulder function following reverse shoulder arthroplasty (RSA), but medialization of the centre of rotation (COR) in RSA may cause complications like limited range of motion (ROM), luxation of the prosthesis, and scapular notching, where the lower part of the scapular neck becomes eroded due to impingement against the humeral component. Joint centre lateralization with a bone transplant placed underneath the glenoid component (BIO-RSA) was introduced to maximize ROM in the prosthetic joint, increase stability and to prevent scapular notching. In recent years it has been claimed that lateralization of the COR with BIO-RSA decreases the risk of the aforementioned complication, but no consensus on when or how to lateralize the COR exists as of today. This knowledge will also be of critical importance when it comes to decision making on how these patients are best treated. Results from this research project is expected to have a significant impact on how these patients are treated in the future, both nationally and internationally.

The purpose of this study is to compare functional results between patients with bony increased offset-reversed shoulder arthroplasty (BIO-RSA) and conventional reverse shoulder arthroplasty (RSA) to investigate if lateralization of the glenosphere yields superior outcomes and fewer complications after 2 years.

This multicenter study will include 130 patients in 4 hospitals scheduled for RSA. Patients will be asked to participate in a blinded RCT, where they are randomly assigned to either BIO-RSA or conventional RSA. Functional results will be measured primarily by the patient-reported outcome measure Western Ontario Osteoarthritis Shoulder (WOOS), but they will also be examined by a physiotherapist and CT imagery will be assessed by a radiologist.