As with all major surgical procedures, complications can occur. Some of the most common complications following artificial shoulder replacement are infection, loosening, dislocation, and nerve injury. This is not intended to be a complete list of the possible complications, but includes the most common complications.

Infection
Infection can be a very serious complication following an artificial joint replacement. The chance of getting an infection following artificial shoulder replacement is probably somewhere around 1%. Some infections may show up before you leave the hospital. Others may not become apparent for months, or even years, after the operation. Infection can spread into the artificial joint from other infected areas. Your surgeon may want to make sure that you take antibiotics when you have dental work or surgical procedures on your bladder and colon to reduce the risk of spreading germs to the joint.

Loosening
The major reason that artificial joints eventually fail continues to be a process of loosening where the metal or cement meets the bone. There have been great advances in extending how long an artificial joint will last, but all will eventually loosen and require a revision. Patients routinely achieve 12-15 years of service and longer from an artificial shoulder, but in some cases the artificial shoulder will loosen earlier than that. A loose prosthesis is a problem because it causes pain. If the pain becomes unbearable, another operation may be required to revise the shoulder replacement.

Dislocation
Just like your real shoulder, an artificial shoulder can dislocate, meaning the ball comes out of the socket. There is a greater risk just after surgery, before the tissues have healed around the new joint, but there is always a risk. The therapist will instruct you very carefully how to avoid activities and positions that may have a tendency to cause a shoulder dislocation. A shoulder that dislocates more than once may have to be revised (which means another operation) to make it more stable.

Nerve Injury
All of the large nerves and blood vessels that go to the arm and hand travel through the armpit (axilla). Due to the fact that the operation is performed so close to these important structures, it is possible to injure either the nerves or the blood vessels during surgery. The result may be temporary if retractors holding them out of the way have stretched the nerves. It is very uncommon to have permanent injury to either the nerves or the blood vessels, but it is possible.