This study states that the Progressive glenoid bone loss and humeral head subluxation occur in primary glenohumeral osteoarthritis (GHOA), but less is known about the rate and pattern by which this occurs. The purpose of this study was to determine how glenohumeral subluxation and glenoid bone loss changed over time in shoulders that underwent arthroplasty and had been evaluated with radiographs at 1 or more time points over the 5-15 years before arthroplasty. We retrospectively identified 48 shoulders that had been evaluated with high-quality radiographs both before arthroplasty and at least once 5-15 years earlier. Axillary radiographs were used to classify glenoid morphology using the modified Walch classification on the oldest, most recent, and all intervening radiographs. The mean interval time between the oldest and most recent radiographs was 8.9 years (range 5-15 years). Nineteen patients had a single intervening radiograph. In primary GHOA, humeral head subluxation and glenoid bone loss do progress over time, but not universally and not always through the same pathway. Shoulders presenting with posterior subluxation (B types) remained posteriorly subluxed. Shoulders presenting with concentric arthritis developed an eccentric pattern 20% of the time.

Reference link- https://www.jshoulderelbow.org/article/S1058-2746(20)30467-5/fulltext