Acromioclavicular Joint (AC JOINT) Arthritis
The AC joint is a joint between the clavicle (collar bone) and the acromion (the shoulder blade bone). It is almost routinely arthritic by the time we are 40. However, only a small proportion of people develop symptoms. In my experience it is people with heavier lifting jobs that tend to develop symptoms and I have seen plenty of younger people who like to do dumbbell weight activities who have developed symptomatic AC joint arthritis.
Treatment in the first instance consists of simple measures such as anti-inflammatory medications, movement therapy (strengthening with a physio) and hydrotherapy, hot packs, avoiding movements that cause pain and occasional injections into the AC joint with steroid medication. Just simply time may allow the inflammation associated with an irritated joint to settle. I am sure there are plenty of 90 year olds who had AC joint pain at some time in their lives and never needed an injection or surgery for it.
If things are unbearable and not settling then surgery can be considered. this usually consists of arthroscopic (telescope) surgery. We look inside the shoulder joint and grind away the tip of the collar bone so that the two bones in the shoulder do not touch anymore.
You will not be able to perform lifting activities for around six weeks after surgery, and complete resolution of symptoms make take between six and twelve months. It is however in my experience a very rewarding operation.