The acromioclavicular joint (ACJ) is where your collarbone meets your shoulder blade. It enables you to make overhead movements and movements across your body with your arm. It is also used in pushing, pulling and lifting. The most common problems with the ACJ joint result from injuries, overuse or wear and tear.
A fall or direct impact can injure the ligaments of the ACJ, resulting in pain and loss of movement in your shoulder. ACJ injury is commonly referred to as shoulder separation, although the main ball and socket shoulder joint below may be unaffected.
ACJ pain can commonly occur with wear and degeneration (arthritis) of the joint itself or through overloading such as through excessive weights in the gym. This can cause pain felt particularly with overhead activities at the end of the collarbone. ACJ degeneration and pain can be more common with heavy overhead activities and work such as construction or plastering, and in younger patients from overloading such as through intensive and heavy weights in the gym. Physiotherapy exercises can help reduce pain. Steroid injections may also be an option and for cases that continue with pain despite other treatments, surgery may be required.