These authors sought to determine how glenohumeral subluxation and glenoid bone loss changed over time in 48 shoulders that underwent arthroplasty and had been evaluated with standardized high-quality axillary radiographs
at 1 or more time points over the 5-15 years before arthroplasty. The mean interval time between the oldest and most recent radiographs was 8.9 years (range 5-15 years).
Below is an example of how glenoid morphology progressed over roughly an 8-year period of time from an A1 glenoid to a B3 glenoid. Note the standardization of the axillary "truth" views that enabled comparisons of the glenohumeral pathoanatomy over time. The patient was a 43-year-old male (body mass index 26.6) at initial presentation for symptomatic right shoulder osteoarthritis and went onto an anatomic total shoulder arthroplasty. From presentation to year 5, the glenoid morphology remained A1 with 3 intervening radiographs documented. At year 6, the patient was noted to have a B1 glenoid (top right), a B2 glenoid at year 7 (bottom left), and a B3 glenoid at year 8 before proceeding with surgery (bottom right).
On each axillary view, the glenoid type
were documented.
Glenoid morphology on the earliest radiograph was classified as A1 in 22, A2 in 13, B1 in 1, B2 in 9, B3 in 1, and D in 2 shoulders.
Walch A patterns identified on early radiographs most commonly maintained an A pattern over time, but 20% developed eccentric wear with 5 of 35 becoming B type and 2 of 35 becoming a D type before arthroplasty.
Only 15% (2/13) of A2 glenoids developed eccentric wear compared with 32% (7/22) of A1 glenoids.
Comment: This study demonstrates that glenohumeral pathoanatomy can be well characterized using the axillary "truth" view without the additional expense and radiation dosage of a CT scan.
This study also demonstrates that the description of glenoid pathoanatomy cannot be constrained to discrete static "types", but rather the amount of bone loss, change in version, and humeral decentering each exist on a continuum from "none" to "a lot" with progressive transitions from one type to another.
