There is a particular type of shoulder arthritis that has a unique constellation of abnormal features and associated deformity that becomes worse with time. This type of shoulder arthritis is relatively common but challenging to treat. Conventional anatomic shoulder replacements tend to fail early in patients with this type of arthritis. The cause of this particular type of arthritis is poorly understood.

Associate Professor Raniga and his colleagues where the first to show that these shoulders have significant difference in the humerus (upper arm) that may be a cause of this type of arthritis. Furthermore, surgeons need to be aware of this difference in anatomy when they do shoulder replacement to improve patient outcomes.