When is a shoulder replacement indicated?
The shoulder joint can be replaced by an artificial shoulder replacement for pain caused by arthritis or when the shoulder is severely fractured and not amenable to repair.
Arthritis is when the cartilage on the ends of the bones is gone and there is bone rubbing on bone in the joint. Arthritis can be caused by fractures, dislocations, rheumatoid disease, torn rotator cuff tendons, infection, prior shoulder surgery or just by wear and tear over time.
The shoulder is a ball and socket joint. The ball is the upper part of the arm bone (humerus) and is called the humeral head. The socket is smaller and is part of the shoulder blade (scapula).
What part of the shoulder is replaced?
The ball is held in the socket by ligaments and by the rotator cuff tendons. The rotator cuff muscles start on the shoulder blade and turn into tendons which attach to the ball. In shoulder replacement surgery the ball is replaced with a metal ball attached to a stem.
The stem is inserted down the shaft of the humerus. Sometimes cement is utilized to keep the stem in place. The socket sometimes is replaced with a plastic piece which is usually fixed to a groove in the socket with cement. Whether a socket is used or not depends upon how bad the arthritis is in the shoulder and whether the rotator cuff tendons are intact.
How long does the surgery take?
The surgery takes about two to three hours, including time for anesthesia to be done. Anesthesia is usually a general anesthetic with a local anesthetic that can be used to numb the whole arm. This is done by blocking the nerves as they come out of the neck (interscalene block). Some patients must have medical clearance for surgery by their family doctor prior to surgery.