Total Shoulder Replacement

Total shoulder replacement arthroplasty is a well-established surgery for restoring comfort and function to the arthritic shoulder. In this procedure the arthritic ball is replaced by a smooth met- al ball fixed to the arm bone (humerus) by a stem that fits within it.Although shoulder joint replacement is less common than knee or hip replacement, it is just as successful in relieving joint pain.
The Shoulder surgery involves replacing the damaged joint ball or humeral head with a metal ball and putting a new smooth plastic surface on the glenoid called the socket. Metal on plastic surfaces rather than metal on metal is the hallmark of virtually all shoulder replacement implant systems. Partial shoulder replacement (or hemi-replacement) may also be indicated with certain severe shoulder fractures of the humeral head. This technique requires the replacement of the ball component only.

Anatomy

Your shoulder is made up of three bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle). The shoulder is a ball-and-socket joint: The ball, or head, of your upper arm bone fits into a shallow socket in your shoulder blade. This socket is called the glenoid.
The surfaces of the bones where they touch are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily. A thin, smooth tissue called synovial membrane covers all remaining surfaces inside the shoulder joint. In a healthy shoulder, this membrane makes a small amount of fluid that lubricates the cartilage and eliminates almost any friction in your shoulder.
The muscles and tendons that surround the shoulder provide stability and support.