Pathomechanics of Glenohumeral Joint Osteoarthritis

Osteoarthritis has a very predictable cascade of effects. First, we’ll see contractures of the anterior soft tissues. This leads to external rotation deficit and further internal rotation contracture.
Rotational deficits lead to increased forces on the joint, flattening of the humeral head, osteophyte formation and eccentric erosion of the posterior glenoid. There is an increased incidence of posteriorly subluxed humeral head and glenoid retroversion.1 The erosion on the posterior aspect of the glenoid is also known as a biconcave glenoid.1