Three-dimensional computed tomography assessment of acromial morphology in Vietnamese patients undergoing arthroscopic surgery for subacromial impingement.

BACKGROUND: Acromial morphology has been implicated in subacromial impingement and may influence the planning of arthroscopic subacromial decompression. Three-dimensional computed tomography (3D-CT) allows standardized anatomical reformatting and quantitative assessment of acromial parameters, but data from Vietnamese surgical patients remain limited. MATERIALS AND METHODS: This single-center descriptive study included 50 patients who underwent arthroscopic treatment for subacromial impingement between January 2023 and June 2025. Acromial morphology was classified according to the Bigliani classification on reconstructed outlet views derived from 3D models. Quantitative measurements included the critical shoulder angle (CSA), acromion index (AI), lateral acromial angle (LAA), and acromiohumeral distance (AHD) in both static and simulated dynamic positions. RESULTS: Preoperatively, no patient had a type I acromion. Type II and type III acromial morphologies were identified in 39/50 (78.0%) and 11/50 (22.0%) patients, respectively. Mean preoperative values were 0.82 ± 0.03 for AI, 38.29 ± 0.63° for CSA, 61.47 ± 2.26° for LAA, 5.26 ± 0.66 mm for static AHD, and 0.96 ± 0.57 mm for simulated dynamic AHD. AI showed a moderate inverse correlation with LAA (r = -0.44, p < 0.01). CONCLUSIONS: In this Vietnamese surgical cohort, 3D-CT enabled standardized characterization of acromial morphology and related anatomical indices. These findings offer a preliminary morphological description of the cohort and may contribute to a better understanding of subacromial anatomy in patients undergoing arthroscopic treatment for subacromial impingement. Further studies including asymptomatic controls and correlations with clinical outcomes are needed to clarify the broader clinical relevance of these measurements.