This prospective cohort asks whether the critical shoulder angle (CSA) predicts outcomes after arthroscopic rotator cuff repair. The CSA combines glenoid inclination and lateral acromial extension and is a known predictor of cuff pathology. 53 patients with atraumatic full-thickness tears were followed for 24 months.
A large CSA tells you a patient is more likely to have torn their cuff, but this study says it does not tell you they will do worse after you repair it. That distinction matters. The CSA is a strong diagnostic and pathogenesis marker, not a prognostic one for arthroscopic repair of atraumatic full-thickness tears at 2 years.
Remember the mechanism for boards: a large CSA (superior glenoid inclination plus lateral acromial extension) increases glenohumeral shear and raises supraspinatus load by about 35%.
The key caveat is that this study measured only symptoms and function, not healing. It did not obtain MRI or ultrasound to assess retear, so the biomechanical concern that a high CSA compromises repair integrity remains open. With only 18 patients above 38 degrees and 2-year follow-up, do not over-read a negative result. This does not settle whether lowering the CSA surgically changes outcomes.
This prospective cohort asks whether the critical shoulder angle (CSA) predicts outcomes after arthroscopic rotator cuff repair. The CSA combines glenoid inclination and lateral acromial extension and is a known predictor of cuff pathology. 53 patients with atraumatic full-thickness tears were followed for 24 months.
A large CSA tells you a patient is more likely to have torn their cuff, but this study says it does not tell you they will do worse after you repair it. That distinction matters. The CSA is a strong diagnostic and pathogenesis marker, not a prognostic one for arthroscopic repair of atraumatic full-thickness tears at 2 years.
Remember the mechanism for boards: a large CSA (superior glenoid inclination plus lateral acromial extension) increases glenohumeral shear and raises supraspinatus load by about 35%.
The key caveat is that this study measured only symptoms and function, not healing. It did not obtain MRI or ultrasound to assess retear, so the biomechanical concern that a high CSA compromises repair integrity remains open. With only 18 patients above 38 degrees and 2-year follow-up, do not over-read a negative result. This does not settle whether lowering the CSA surgically changes outcomes.