Quick Search

ACJ Osteoarthritis

ACJ is the short name for the acromio-clavicular joint. This is the joint where the clavicle (collar bone) meets the top of the acromion (shoulder blade). This joint is held in place by ligaments and a capsule - a sleeve of fibrous tissue that encircles the joint.

ACJ osteoarthritis is the term for degenerative changes that occur in the joint. This condition most commonly appears in middle age (over 40). Bones of the joint can wear down and develop spurs or osteophytes. This can happen with age or with excessive use of the joint, particularly sports involving throwing or lifting.

ACJ osteoarthritis can also stem from a previous injury, such as dislocation of the AC joint. The degeneration in the bone can in turn cause damage to the ligaments, and the subacromial bursa (cushioning membrane between the ACJ and the shoulder joint) can become inflamed, inhibiting movement.

To help to prevent osteoarthritis, it is advisable to maintain a healthy weight, keep up muscle strength with exercise and minimise repetitive overhead lifting.


The upper arm may feel weak, and there may be aching or pain on lifting the arms over the head. The joint may swell and sleeping may be painful.

Click here for treatment information