Arthritis commonly affects the acromioclavicular joint. AC Joint pain not be well localised to the AC joint. Pain is worse when lifting the arm overhead. There is often a tender bony lump over the top of the shoulder where the AC joint lies if it is arthritic. Most AC joint pains will settle with rest and simple pain tablets like Panadol and Ibuprofen. If it doesn’t then a cortisone injection can be placed into the AC joint. This can be done under ultrasound guidance. If the symptoms from the AC joint don’t settle, then a resection procedure may be suggested. This procedure is done as an arthroscopic (keyhole) operation. The procedure excises the AC joint so that it can no longer cause pain. Surgery creates a larger joint space by removing a segment of bone at the end of the clavicle (collarbone). Resection of a painful AC joint is very effective in relieving pain. The resected AC joint is replaced by fibrous scar tissue that takes the place of the worn out arthritic joint. Compared to a worn out painful AC joint, the resected AC joint is a significant improvement.