The impact of acromial morphology on the localization and size of calcific tendonitis in the rotator cuff.

Objective: This study aimed to investigate the association between acromial morphology and the incidence and extent of calcific tendonitis.

Methods: Ninety-two patients (33 male, 59 female; mean age: 47 ± 9.7) with calcific tendonitis were included in this retrospective study. Critical shoulder angle (CSA), slope angle, lateral acromial angle (LAA), acromion index (AI), acromial type according to Bigliani, and the morphology of the calcific deposits according to Gartner and Heyer were assessed on x-rays. The localization and volume of the calcific deposits were assessed using magnetic resonance imaging (MRI). Patients were divided into 2 groups: CSA < 33° (group 1) and CSA ≥ 33° (group 2).

Results: The median CSA was 33.5° (range=23°-51°), lateral acromial angle (LAA) was 83.6° (range=60°-106°), acromial index (AI) was 0.7 (range=0.4-0.9), and slope angle was 24.1° (range=3°-40°). Lateral acromial angle (P=.000) and AI (P=.000) were statistically different between the 2 groups. Critical shoulder angle was correlated with LAA (P=.000) and AI (P=.000); deposit volumes were correlated with slope angle (P=.001), Bigliani type of the acromion (P=.009), and deposit stage according to Gartner and Heyer (P=.004). There was a correlation between deposit localization and its volume; the size of the deposit increased anteriorly (P=.000).

Conclusion: This study has shown that CSA failed to quantify a patient's predisposition to calcific tendonitis. However, the findings demonstrate a relationship between the morphological parameters in the sagittal plane, such as acromial slope and deposit volume, which deserve further research.

Level of evidence: Level III, Prognostic Study.