Acromioclavicular Joint Disk Tearing in Young Non-Arthritic Individuals: A Case Series

INTRODUCTION: Degeneration of the fibrocartilaginous acromioclavicular (AC) joint disk can become significant in later life and lead to primary osteoarthritis and shoulder pain. Younger, non-arthritic individuals may develop residual shoulder symptoms due to tearing of the disk itself. CASE REPORT: Six patients (seven shoulders) were included in this case series. They were athletic and between the ages of 17 and 22. They typically presented with lingering symptoms of pain, popping, and instability in and around the AC joint after prior trauma or injury involving their shoulder. For most, symptoms lasted longer than 2 months before they sought additional treatment. Plain films were negative, and magnetic resonance imaging occasionally demonstrated pathology at the AC joint. Conservative treatment provided limited relief. All patients included in this series underwent arthroscopic distal clavicle resection. Intraoperatively, the disk could be seen as acutely torn or degenerative in all cases. In some, it was hypermobile and could be manually subluxed in and out of the joint. CONCLUSIONS: A torn AC joint disk may cause lingering symptoms in young patients without radiographic evidence of arthritis. Further study is needed to determine if these findings are truly causative or merely incidental.