Damage to the normally smooth cartilage of the shoulder joint causes arthritis. This is an irreversible process and usually takes many years to develop and cause symptoms.
The most common cause is age related wear of the joint known as osteoarthritis. Other causes include trauma to the shoulder including dislocations and chronic inflammatory conditions such as rheumatoid arthritis. These can lead to relatively rapid destruction of the joint. The main symptoms of shoulder arthritis are pain, stiffness and loss of function.
Early arthritis can be treated non-operatively with simple pain medication and physiotherapy to help mobilise the joint and strengthen the shoulder muscles.
Advanced arthritis can be treated by joint replacement surgery. The surgery removes the damaged and worn joint surfaces of the shoulder and replaces them with a prosthetic ball and socket joint. The main aim of the surgery is to treat the pain associated with an arthritic shoulder but most patients also benefit from increased range of motion of the joint after surgery.
Some arthritic shoulder joints also have damage to the tendons of the shoulder muscles. In these cases a normal shoulder replacement will function poorly and may become unstable. A reverse shoulder replacement prosthesis that has the socket on the arm side and the ball part of the joint on the shoulder-blade side is preferred in these cases.
Surgery is performed under a general anaesthesia and patients usually stay in hospital for two to three days. A gentle physiotherapy program is started after surgery to prevent stiffness and help regain shoulder function.
Advances in surgical techniques and improvement in prosthetic materials have allowed the majority of shoulder joint replacements to last ten years or more.