Association Between Acromion Morphology and Non-Traumatic Rotator Cuff Injury Among Young Adult Filipinos in a Tertiary Hospital: Cross-sectional Study

Introduction

Rotator cuff injury (RCI) is among the most common shoulder pathologies, significantly affecting quality of life. Acromial morphology has been implicated as a predisposing factor, but limited local data exist. The Bigliani-Kitay classification defines four acromion types: flat (I), curved (II), hooked (III), and convex (IV). MRI is the preferred modality for assessing both acromial morphology and RCI.

Objective

To assess the association between acromion morphology and RCI among patients undergoing shoulder MRI at Makati Medical Center, a tertiary hospital in the Philippines.

Methods

A retrospective review of shoulder MRI scans performed from January to December 2019 was conducted. Patients with shoulder pain were included as cases. Acromion morphology and presence of RCI (tendinosis, partial, or full-thickness tears) were documented. Images were interpreted by radiologists accredited by the Philippine College of Radiology.

Results

Of 132 patients (mean age: 31.2 ± 5.4 years), 65.9% were male. The period prevalence of RCI was 58.3% (n = 77). There was no significant sex-based difference in RCI prevalence ( p = 0.4036). RCI was significantly associated with Type II (70.5%, p < 0.00001) and Type III (100%, p = 0.00158) acromion morphologies. No significant association was found for Types I and IV.

Conclusion

Type II and Type III acromial morphologies are significantly associated with higher prevalence of RCI. Recognition of these morphologies on MRI may help identify patients at increased risk and allow for early intervention.

Advances in knowledge

• Confirms a statistically significant association between Type III (hook-shaped) acromion and rotator cuff injury (RCI) in a Filipino young adult population.

• While associated with RCI as well, type II acromion is most prevalent in the study population.

• This is among the first studies in the Philippines to characterize acromial types in relation to documented RCI.

Application to patient care

• Early identification of type III acromion may support clinical suspicion for rotator cuff pathology, improving diagnostic accuracy.

• Patients with type III acromion may benefit from earlier referral to physical therapy or orthopedic evaluation.

• Incorporating acromial morphology in radiology reports may enhance multidisciplinary communication between radiologists, primary care providers, and orthopedic surgeons.