Characteristics of acromial morphology in patients with painful shoulders from Indonesia

Shoulder pain is a common reason for patients to seek care from general practitioners or orthopaedic specialists. Prior studies suggest a correlation between acromial morphology and shoulder pathologies. This study aimed to determine acromion characteristics in the Indonesian population and evaluate associations between acromion type, radiographic parameters, sex, and shoulder disorders.

A cross-sectional study was conducted on 487 patients with shoulder disorders, using consecutive sampling and data from our institution's radiology database (2020-2021). Acromion morphology was classified using the Bigliani system. Diagnoses were based on clinical and radiological records. Radiographic parameters assessed included critical shoulder angle (CSA), acromion index (AI), lateral acromial angle (LAA), acromioclavicular (AC) joint distance, acromiohumeral (AH) joint distance, and acromial tilt.

Among 487 patients, type II acromion was most common (59.5%), followed by type I (33.3%), type IV (4.5%), and type III (2.7%). Mean CSA was 38.36 ± 5.13, AI 0.72 ± 0.09, LAA 72.52 ± 6.01, AC joint distance 3.18 ± 0.89, AH distance 8.61 ± 1.86, and acromial tilt 28.84 ± 4.52. No significant association was found between acromion type and shoulder disorders (p = 0.34), or between sex and acromion type (p = 0.516). Radiographic parameters also showed no significant correlation with shoulder disorders.

Type II acromion was the most prevalent in this Indonesian population. No significant associations were observed between acromion type, sex, or radiographic parameters and shoulder pathologies. Acromial morphology may represent normal anatomical variation rather than a pathological finding.