Partial shoulder replacement, also called shoulder hemiarthroplasty is a surgical procedure during which the upper bone in the arm (humerus) is replaced with a prosthetic metal implant, whereas the other half of the shoulder joint (glenoid or socket) is left intact. This surgical procedure is indicated in severe, and rare conditions of shoulder osteoarthritis in which the only the humeral head or ball of the joint is damaged. Osteoarthritis is a degenerative condition in which the cartilage that allows smooth movement in the joints wears away causing the adjacent bone to rub against each other resulting in pain and stiffness. In such conditions, replacement of the damaged portion of the humerus will reduce the friction as bone ends can no longer come in contact and thus relieve pain. Often shoulder osteoarthritis involves both the shoulder ball and shoulder socket and requires a total shoulder replacement instead of just a partial shoulder replacement. A common indication for shoulder hemiarthroplasty is avascular necrosis (AVN) when the humeral head loses blood flow and collapses.
Surgery remains as a sole treatment option when all possible conservative means of treatment such as rest, anti-inflammatory medications, physical therapy have been ineffective in resolving your symptoms. While the procedure may relieve your pain and other symptoms, there may also be associated risks and complications as with any major surgery.
Potential risks and complications that may occur following shoulder hemiarthroplasty include infection, instability, fractures of the humerus or scapula, shoulder stiffness, damage to the blood vessels and nerves.