There are numerous types of arthritis; however, the form usually found in the AC joint is osteoarthritis (OA). The majority of arthritis cases involving the acromioclavicular joint are the result of previous trauma, infection, or wear-and-tear, all of which can lead to the development of OA.

Osteoarthritis is categorized as either primary or secondary. Primary OA refers to a generalized condition brought on by normal wear-and-tear that affects various joints throughout the body; whereas, secondary osteoarthritis refers to arthritis stemming from a previous trauma to the joint. Since injuries to the AC joint are common throughout the athletic society, secondary OA is frequently seen within the sports medicine community.

The pain associated with osteoarthritis is usually constant and localized to the affected joint. This pain may be caused by inflammation or muscle strains caused by impact to the shoulder.