Shoulder arthritis

OSTEOARTHRITIS OF THE SHOULDER

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.

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.

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 2 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.

Types of pain management

Non-operative Management

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.

Operative Management

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 and polyethylene (a medical-grade plastic). The humeral (upper arm) prosthesis consists of a metal ball that replaces the head of the humerus, and a body and stem that is secured into the upper arm bone. The glenoid (shoulder blade socket) prosthesis is made of a special polyethylene, and is designed to replace the socket part of the joint.

There are two types of shoulder replacement procedures. If only the metal humeral components are used, the procedure is called a hemi-arthroplasty. If both the humeral components and the glenoid prosthesis are used, then the procedure is called a total shoulder arthroplasty. The surgeon determines whether you have a total shoulder replacement or hemiarthroplasty depending on your age and whether your rotator cuff tendon is intact and working.

Metal Prostheses

Medical Grade Plastic Prostheses

If operative management is elected

How is the operation done?

The operation involves coming into hospital for about 3-5 days. Under a general anaesthetic, an 8-10 cm incision is made from the shoulder down the front of the arm through which the joint surfaces are surgically replaced. The operation takes approximately two hours and x-rays of the prosthesis are taken in the recovery room. 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 metallic head and stem. 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 we will start gentle movement of your arm with physiotherapy.

Complications

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.