This Level III case-control study of 200 patients examines whether the critical shoulder angle (CSA) independently predicts the type and severity of degenerative shoulder disease. It tests whether more extreme CSA values correlate with worse pathology after controlling for age, smoking, BMI, and work demands.
When a patient presents with a rotator cuff tear, measuring the CSA on the standard AP radiograph you already have tells you something about their underlying anatomy — not just their tear. A CSA above 34° identifies a structurally higher-risk shoulder, which is relevant when counseling patients about retear risk after repair and when considering whether glenoid-correcting procedures have a future role.
The flip side matters equally: a patient with primary concentric glenohumeral OA and a CSA below 33° is in the anatomically expected range for that disease. CSA and age were the only two variables that independently predicted concentric OA in this cohort. Everything else washed out.
The dose-response between CSA and tear size (isolated supraspinatus at 36° vs. Large tear at 40°, P = .03) suggests that anatomy may influence not just whether a patient tears, but how far the tear progresses.
The authors explicitly flag that CSA correction. Via glenoid inclination adjustment at the time of shoulder arthroplasty or as a standalone procedure. Is a logical next step that this data supports but does not yet prove.
This Level III case-control study of 200 patients examines whether the critical shoulder angle (CSA) independently predicts the type and severity of degenerative shoulder disease. It tests whether more extreme CSA values correlate with worse pathology after controlling for age, smoking, BMI, and work demands.
When a patient presents with a rotator cuff tear, measuring the CSA on the standard AP radiograph you already have tells you something about their underlying anatomy — not just their tear. A CSA above 34° identifies a structurally higher-risk shoulder, which is relevant when counseling patients about retear risk after repair and when considering whether glenoid-correcting procedures have a future role.
The flip side matters equally: a patient with primary concentric glenohumeral OA and a CSA below 33° is in the anatomically expected range for that disease. CSA and age were the only two variables that independently predicted concentric OA in this cohort. Everything else washed out.
The dose-response between CSA and tear size (isolated supraspinatus at 36° vs. Large tear at 40°, P = .03) suggests that anatomy may influence not just whether a patient tears, but how far the tear progresses.
The authors explicitly flag that CSA correction. Via glenoid inclination adjustment at the time of shoulder arthroplasty or as a standalone procedure. Is a logical next step that this data supports but does not yet prove.