This retrospective cohort asks whether arthroscopic lateral acromioplasty can reduce the critical shoulder angle (CSA) enough during rotator cuff repair without harming the deltoid origin. Ninety patients were split by preoperative CSA: below 35° (anterior acromioplasty only) versus 35° or higher (added lateral resection). The key question: how low can you realistically drive the CSA, and is it safe for the deltoid?
The CSA is a scapular morphology marker: an angle above 35° raises supraspinatus load and superior humeral head translation, which drives degenerative cuff tears.
The practical rule from this paper is a ceiling on what surgery can fix. Lateral acromioplasty reliably drops a CSA in the 35°–40° range below threshold, but an angle above 40° stays elevated in 83% of cases. Bone removal is capped by the deltoid origin, so you cannot simply resect more.
Use this for expectation-setting and planning. When you see a very high CSA with a large or massive tear, counsel that the angle may not normalize and consider improved preoperative mapping of where to resect.
Reassuringly, the deltoid tolerated resection well, with no detachment or dysfunction even at 8° of correction. Whether residual CSA elevation actually causes clinical retears remains unproven here, so treat CSA correction as a reasonable adjunct, not a guarantee.
This retrospective cohort asks whether arthroscopic lateral acromioplasty can reduce the critical shoulder angle (CSA) enough during rotator cuff repair without harming the deltoid origin. Ninety patients were split by preoperative CSA: below 35° (anterior acromioplasty only) versus 35° or higher (added lateral resection). The key question: how low can you realistically drive the CSA, and is it safe for the deltoid?
The CSA is a scapular morphology marker: an angle above 35° raises supraspinatus load and superior humeral head translation, which drives degenerative cuff tears.
The practical rule from this paper is a ceiling on what surgery can fix. Lateral acromioplasty reliably drops a CSA in the 35°–40° range below threshold, but an angle above 40° stays elevated in 83% of cases. Bone removal is capped by the deltoid origin, so you cannot simply resect more.
Use this for expectation-setting and planning. When you see a very high CSA with a large or massive tear, counsel that the angle may not normalize and consider improved preoperative mapping of where to resect.
Reassuringly, the deltoid tolerated resection well, with no detachment or dysfunction even at 8° of correction. Whether residual CSA elevation actually causes clinical retears remains unproven here, so treat CSA correction as a reasonable adjunct, not a guarantee.