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Does the critical shoulder angle decrease after anterior acromioplasty?



No clinical studies to date have analyzed the critical shoulder angle (CSA) following anterior acromioplasty. Our study’s main objective was to measure the change in the CSA after acromioplasty.

Materials and methods

Ninety patients were included in this retrospective series. The CSA and the type of acromion were evaluated before and after surgery.


The average CSA for patients before surgery was 35.9° (± 3.7, 26.2, 44.2) and 33° after the acromioplasty (± 3.5, 24.8, 41.4). The decrease was significant and 2.9° on average (± 2.2, − 2.2, 11.9, p = 0.000). Preoperatively, 58% of patients had a CSA ≥ 35° (n = 52) and 24% postoperatively (n = 22, p = 0.000).


Standardized anterior acromioplasty allows for a significant decrease in the CSA without lateral resection of the acromion. This study confirms the tight link between the CSA and the anterior acromion as well as the interest of this angle to quantify acromioplasty whether anterior or lateral.

Level of evidence

Level IV, Case Series, Retrospective design.

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Correspondence to Anselme Billaud.

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AB, EC, LP, PA, YC, and P-H F declare that they have no conflict of interest.

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Billaud, A., Cruz-Ferreira, E., Pesquer, L. et al. Does the critical shoulder angle decrease after anterior acromioplasty?. Arch Orthop Trauma Surg 139, 1125–1132 (2019).

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  • Acromioplasty
  • Critical shoulder angle
  • Rotator cuff tear
  • Rotator cuff repair