- Why may someone need a shoulder joint replacement?
- What symptoms may mean a shoulder replacement should be considered?
- What does a shoulder joint replacement involve?
- What are the complications of a shoulder replacement?
- What happens after the operation?
- Are there any alternatives to a shoulder replacement?
Why may someone need a shoulder joint replacement?
The shoulder joint is what is called a ‘ball and socket’ joint. This means that it consists of a spherical shaped piece of bone at the top of the humerus (the bone at the top of the arm) that slides against a cup shaped area of bone made up of the shoulder blade and collar bone.
It is unusual in that it can move in almost all directions including in a circular motion, something that no other joint in the body can do. However, this makes it prone to problems with its movement, such as inflammation of the muscles and tendons involved in rotating the joint and wearing away of the tough lubricating surface material called cartilage.
The main reason for considering any joint replacement, including a shoulder joint replacement, is as a result of severe osteoarthritis (wear and tear) in the joint. Shoulder joint replacements are not performed anything like as frequently as hip or knee replacements. This is partly because the shoulder is not a weight-bearing joint (ie it does not have to carry the load of the body throughout life as the hip and knee joints do). It is also because osteoarthritis (OA) of the shoulder does not affect the individual’s ability to remain mobile whereas OA of the hip or knee can significantly restrict a person’s mobility and therefore their independence.
What symptoms may mean a shoulder replacement should be considered?
Most shoulder joint disorders can either be alleviated or treated with drugs, injections or physiotherapy. However whenever the joint is severely restricted in its movement or causes severe daily pain resulting in significant disability or distress for the individual, a shoulder joint replacement may be considered.
How are shoulder joint problems diagnosed?
The diagnosis of a significant shoulder problem starts with the history (the description by the patient of his or her symptoms and their severity). If a shoulder replacement is being considered, the degree of pain and restriction of movement and its effect on the patient’s quality of life will be especially important to allow the doctor and patient to decide whether a replacement operation is warranted.
The doctor will then examine the joint looking for tenderness, swelling, deformity and restriction of movement. Following this, it would be usual for an x-ray to be done and possibly a more detailed examination of the shoulder such as a magnetic resonance image (MRI) scan that provides detailed images of the inside of the joint.
What does a shoulder joint replacement involve?
The operation to replace the shoulder joint is done under general anaesthetic and may be done in one of two ways.
If the socket of the joint is thought to still be in good condition with little in the way of wear and tear, this may be left alone with only the ‘ball’ part of the joint being replaced. This is known as a ‘hemi-arthroplasty’ (half joint replacement). This tends to be done following fractures of the shoulder resulting in avascular necrosis (explained earlier) of the top of the humerus, since in these circumstances the socket part of the joint often remains undamaged.
A hemi-arthroplasty has the advantage that the socket part of the joint tends to be more difficult to replace so leaving this alone makes the operation more straightforward.
In most cases of OA, both parts of the shoulder joint will be affected and in these cases a ‘total arthroplasty’ or full joint replacement will need to be done. The ball joint is removed with a special saw and the socket part of the joint is prepared to receive a new surface. A new ball joint is usually made of a ball-shaped metal knob on a stem that slides into the centre of the shaft of the humerus. It may be held in place with special cement (a cemented joint) or may be uncemented, which involves the stem of the replacement having a mesh of holes in it, which allow new bone to grow through the holes to stabilise it.
What happens after the operation?
Once the operation to replace the shoulder has been done, pain relief will be given until the pain settles down. The patient will then be given instructions about how to gradually start using the arm again in such a way as to prevent stiffening of the shoulder without putting too much strain on it and therefore risking dislocation. Physiotherapy will help to mobilise the joint and strengthen the muscles around it. Your surgeon will advise on when you can resume driving and playing sport.
Are there any alternatives to a shoulder replacement?
In most cases the answer to this question is yes. Generally speaking a shoulder replacement operation is the last resort since there are often other types of treatment which will reduce the pain or restore enough movement in the shoulder to enable the individual to carry on life without too many restrictions.
Alternative medical treatments include:
- Anti-inflammatory painkillers not only help to relieve any pain from the joint but also reduce inflammation within the shoulder.
- Physiotherapy can be very useful in increasing the movement in the shoulder joint in many cases and can also help to settle inflammation in the tissues.
- Another way of administering anti-inflammatory’ injections. It is injected directly into an inflamed joint, can be very effective in reducing the pain and inflammation of the joint.
- Arthroscopy is a technique that involves looking inside a joint with the use of a special telescope (what most people have come to know as ‘keyhole surgery’). In certain cases they can be helpful in visualising the problem inside the joint and are sometimes used to perform operations through the telescope.
- Occasionally the specialist may advise a procedure called a manipulation under anaesthetic (MUA) of the shoulder. This is exactly what it says, ie under general anaesthetic the specialist carefully manipulates the joint in ways that would not be possible if the patient was not anaesthetised (due to the pain it would cause). The theory is that this can break down any scar tissue inside the joint and allow greater freedom of movement afterwards.