The shoulder is the most mobile of all joints. Unfortunately it can wear out, which is known as Osteoarthritis.
The shoulder joint is considered to be one of the most complex joints in the body. It is made up of three main bones: the scapula, clavicle and humerus. The shoulder joint is unique in that the ball of the upper arm bone (the humeral head) is two times larger than the socket of the shoulder blade (the glenoid). This creates a very mobile joint, but demands an extensive array of tendons, ligaments and muscles to keep the joint together. These together allow the smooth movement found in the healthy shoulder.
The main shoulder joint (the glenohumeral joint) allows more movement than any other joint in the body. It is responsible for one to raise their arm, to put their arm up their back and to bring it out to the side. The image below depicts a normal shoulder:
Above: X-ray of normal shoulder
Unfortunately a joint like this can wear out like any other joint in the body and can therefore develop arthritis. This causes pain and joint destruction. The following three types of arthritis are the most common sources of joint damage seen in the shoulder:
- Osteoarthritis is a disease which involves the breakdown of the tissue (cartilage) that normally allows the joint to move smoothly. When the gliding surface of the cartilage is gone, the bones grind against each other, creating popping sounds, pain and loss of normal shoulder movement. This condition occurs primarily in people over the age of 50. Osteoarthritis commonly affects the shoulder, hip and knee.
- Rheumatoid arthritis is considered a systemic disease because it can affect any or all joints of the body. It affects women more often than men, and can strike both old and young. Rheumatoid arthritis causes the body’s immune system to produce a chemical that attacks and destroys the protective cartilage that covers the joint surface.
- Trauma-related arthritis results when the joint is injured, either by fracture, dislocation or damage to the ligaments surrounding the joint causing instability or damage to the joint surfaces.
How do patients present?
Osteoarthritis generally occurs in the 50 year old age group and older. It is usually of gradual onset and slowly progresses with time. Patients usually present with two main symptoms - loss of motion and pain. Pain varies and is usually aggravated by activity. Pain slowly increases over years and eventually keeps one awake at night. It is this symptom that normally brings the patient to see the specialist. The condition can generally be diagnosed by an examination and then by X-rays which show loss of the gap between the shoulder bones (the glenoid and the humeral head).
One also often does a CT scan to confirm the degree of damage to the joint. Once the condition has been diagnosed then treatment generally depends on the severity of the symptoms.
How are these problems treated?
Most cases are initially treated with non-operative management. This usually includes modification of activities, anti-inflammatories and gentle physiotherapy and/or hydrotherapy. Occasionally patients are given a cortisone injection which can give temporary relief. If the patient has tried all these modalities and if the condition is severely limiting their lifestyle then surgery is generally recommended.
When conservative methods of treatment fail to provide adequate relief, total shoulder replacement is considered. The primary purpose of the operation is to relieve pain. The secondary purpose is to increase range of motion. The extent of improvement in your range of motion will depend on the severity of your pre-operative condition, the length of time you have had the problem, the range of motion of your shoulder before the surgery and your commitment to the postoperative rehabilitation.
Total shoulder replacement or shoulder arthroplasty is the replacement of the ball of the upper arm and socket of the shoulder blade with specially designed artificial parts, called prostheses, made of metal or ceramic for the humeral head and polyethylene (a medical-grade plastic) for the socket. The humeral (upper arm) prosthesis consists of a metal or ceramic ball that replaces the head of the humerus which is secured into the upper arm bone. These have now become smaller and are called stemless prostheses as, thanks to modern technology, there is no need to put a stem down the humerus. This stemless prosthesis is pictured below:
The glenoid (shoulder blade socket) prosthesis is made of a special polyethylene, and is designed to replace the socket part of the joint. This is inserted with cement.
There are two types of shoulder replacement procedures:
- A total shoulder replacement is done when you have standard arthritis and the tendons of your rotator cuff are intact.
- The other replacement is called a reverse shoulder replacement which is where the ball is put on the glenoid and the socket on the humerus. This type of replacement is performed when you have no or very poor rotator cuff tendons or poor rotator cuff tissue.
How is the operation done?
In the operation only one tendon needs to be cut for the surgeon to get to the shoulder joint. Your shoulder is dislocated at the time of surgery and the ball of the humerus is replaced by a ceramic head. The glenoid or scapula is replaced with a polyethylene prosthesis that is cemented into the bone. The surgeon will use the ones that best resemble your bones at the time of surgery. The joint will then be relocated and put through a series of movements to make sure it is stable. When the surgeon is happy the tendon at the front of your arm is stitched back in place. Your wound is then closed and you are placed in a sling. You will return to the ward in a sling and with a drain to remove any excess blood. After 24 hours the tubing is removed and we will start gentle movement of your arm.
Complications related to the surgery can occur but are quite rare. A general anaesthetic is used and there are risks related to this. Some of the risks include infection, nerve and blood vessel damage, loosening of the prosthesis, fracture at the time of surgery, dislocation, stiffness and ongoing pain, deep vein thrombosis or pulmonary embolism and the need for revision surgery.
Above left: Arthritic shoulder
Above right: Stemless replacement
Above left: Arthritic shoulder
Above right: Stemless replacement
Frequently Asked Questions
Q: Do I need to donate any of my own blood?
A: No, autologous blood donation is not required and post-operative blood transfusions are rare after this type of surgery.
Q: Do I need to go to a rehabilitation hospital?
A: This is entirely up to you and always depends on how well you manage normally and whether you have help at home.
Q: How long will I stay in hospital?
A: Usually two to three days but it always depends on how you are feeling.
Q: How long will I wear a sling for?
A: The sling only needs to be worn for the first few days after the operation then we encourage you to come out of it as much as possible. It is a good idea though to wear the sling when going out of doors to avoid others from knocking or bumping your shoulder.
Q: When can I drive?
A: Driving a motor vehicle is usually not recommended until two conditions are met:
- It has been at least 6 weeks after the surgery and
- The shoulder is comfortable enough so that when you are standing you can raise your arm to the horizontal position straight out in front of you 20 times.
Using these criteria, we avoid placing the shoulder, passengers, other drivers and pedestrians at risk from a shoulder that cannot perform in emergency situations.
Q: Will my shoulder last forever or will I have to have it replaced in years to come?
A: It is expected that the life-span for the prosthesis will be 10-20 years.