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 very low. 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. 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.

Shoulder replacement implants in today’s market are advanced in design and technology. However, they do not last forever.

Why does an implant wear out?

1) It can become loose

2) An infection can develop near the implant

3) The bone can wear away

4) The implant can wear down

Bone cement that bonds the implant to the bone can crack

Fractures can occur in the shoulder bone or in the implant itself

If your shoulder replacement wears out, you may experience stiffness, pain, swelling and the joint may feel loose. Your shoulder and arm may also look out of alignment and may move or hang strangely.

By being aware of the warning signs, you will know when to contact your surgeon to discuss further treatment options, which may include surgery.

Look out for these signs:

1) New or recurrent pains that occur in the shoulder or arm areas

2) Movement of your shoulder and arm that is painful

3) Your shoulder joint becomes stiff and hard to rotate

4) Redness and swelling appear at your shoulder joint

5) The skin over the shoulder is warm to the touch

6) The shoulder seems to be unstable or hard to control

If you have concerns about your shoulder replacement, contact your physician right away. After your surgeon examines your shoulder, he or she may want to take an X-ray or CT scan to assess your situation and determine the best treatment option.

The operation to replace the arthritic shoulder with an artificial shoulder replacement may be done in one of two ways. If the socket portion of your shoulder is still in fairly good shape, meaning there is still some articular cartilage left on the surface, only the ball portion may be replaced. This is known as a hemiarthroplasty (“hemi” means half and “arthroplasty” means “reconstruction” of a joint). A hemiarthroplasty is commonly done following fractures of the shoulder – either right away instead of fixing the fracture or later if the ball portion looses its blood supply.

If the socket (glenoid) portion of your shoulder is worn away as well, you will need to have it replaced. When both the ball portion and the socket portion of the shoulder are replaced, it is referred to as a total shoulder arthroplasty. To perform an artificial shoulder replacement, you will most likely be placed under general anesthesia. It is difficult to perform any type of regional anesthesia (to just put the shoulder and arm to sleep) that will allow the surgeon to perform a major surgery such as shoulder replacement.

The operation begins by making an incision through the skin in the front of the shoulder.

This is called an anterior approach to the shoulder. Once through the skin, the nerves and major blood vessels are protected and moved to the side. The muscles are also moved to the side. Making an incision into the joint capsule that surrounds the shoulder joint cavity allows entry into the shoulder joint. The surgeon can now look at the surfaces of the joint as he prepares the bone to replace the shoulder joint surfaces.

The ball portion of the humeral head is removed with a bone saw. The hollow inside of the upper humerous (the arm bone) is prepared using a special rasp to allow for the humeral component to be inserted. This is where the metal stem will be placed that is attached to the ball portion of the artificial shoulder.

If the socket portion of your shoulder will be replaced as well, the socket is prepared by using a burr to remove any remaining cartilage on the surface. A hole is usually drilled with the burr to place the stem on the glenoid component into the bone of the scapula.

Finally, the artificial shoulder is inserted and the shoulder is tested to make sure the pieces fit properly. The glenoid component is inserted to replace the shoulder socket. The socket may be held in place with the epoxy cement if your surgeon has chosen to use a cemented type glenoid component.

When the surgeon has determined that everything is satisfactory, the shoulder capsule is sutured together, the muscles are returned to their correct positions and the skin is sutured together.

There are two major types of artificial shoulder replacements – Cemented Prostheses and Uncemented Prostheses.

A cemented prosthesis is held in place by a type of epoxy cement that attaches the metal to the bone. An uncemented prosthesis is held in place by the tight press fit of the uncemented prosthesis into the bone canal. The choice to use a cemented or uncemented artificial shoulder is usually made by the surgeon based on your age, your lifestyle, and the surgeon’s experience.

Each prosthesis is made up of two parts: The humeral component is the portion of the artificial joint that replaces the ball on top of the upper arm bone – the humerus.

The glenoid component replaces the socket of the shoulder that actually is part of the scapula. The humeral component is made of metal. The glenoid component is usually made of a plastic cup that provides the bearing surface. The plastic used is very tough and very slick.