Cases: Senior musculoskeletal radiologists diagnosed fractures of the anterior glenoid rim (osseous Bankart lesions) in 3 patients with shoulder instability who had routine imaging. However, additional assessment suggested that the images were more consistent with heterotopic ossification under an anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion with no true osseous Bankart lesion and no substantial bone loss.
Conclusion: Recognition of the lesion described in this article is important to prevent potential misdiagnosis and may assist in surgical decision-making.