Background to shoulder replacement and shoulder resurfacing surgery
The operations of shoulder replacement and shoulder resurfacing are designed to relieve the symptoms of arthritis in the shoulder. Although, in common with other joint replacements, it is a reasonably successful operation, it is a procedure which does have some hazards and it should only be undertaken for significant shoulder joint symptoms. It is only the patient who knows how severe their symptoms are but reasonable guidelines are as follows.
The surgery is indicated if your shoulder is preventing you from performing normal day to day tasks such as eating, cooking, writing, reading and similar activities due to shoulder joint pain. The main benefit of shoulder resurfacing is the relief of pain so you should consider the operation if you are troubled by pain on a regular basis so that it interferes with activities or it interferes with sleep.
If your shoulder is very stiff and you cannot lift your arm above the shoulder this will not always improve following surgery. Sometimes the shoulder is stiff purely because of the arthritis so it may loosen up following the surgery. Difficulty in lifting the arm above head height is often however caused by deficiencies in the muscles around the shoulder and this may not be helped by a resurfacing.
What is the shoulder joint like?
The shoulder joint is the joint between a ball at the upper end of the humerus or upper arm bone and the glenoid which is a round socket in the shoulder blade. Although the shoulder is basically a ball and socket it is a little more complex than that. The head or ball on the top of the humerus is surrounded by the tendons of some muscles called the rotator cuff muscles. The rotator cuff muscles run between the head of the humerus and the underside of the acromion which is the bony structure which you can feel at the top of your shoulder blade. The acromion is also joined to the outer end of your clavicle or collar bone with a small joint called the acromio-clavicular joint.
The surfaces of the two bones involved are covered with cartilage which is a shiny white lubricated surface.
The shoulder joint is stabilised partly by the shape of the joint but also by its capsule and rotator cuff muscles.
The process of arthritis is the destruction of the articular cartilage surface of the joint. There are two main types of arthritis which affect the shoulder.
Most of the shoulder resurfacings which I carry out are done for rheumatoid arthritis and similar types of arthritis such as psoriatic arthritis. Rheumatoid arthritis is a disease rather than being a simple wearing out process. In rheumatoid arthritis the lining of the joint is inflamed and it is this inflammation which damages the joint surface.
Osteoarthritis is a condition in which the articular cartilage wears out. It can be caused by major injuries to the joint. A lot of the cause is genetic and shoulder osteoarthritis is seen in people who have no particular injury or work history. The condition runs in families and it is a common part of the ageing process. Osteoarthritis is nothing to do with osteoporosis which is a thinning of the bones which causes fractures but does not cause arthritis.
If a shoulder resurfacing is carried out for osteoarthritis the condition of the rotator cuff muscles needs to be assessed. If they are running freely and the problem is purely one of arthritis, the end result will often be very good with the patient able to lift their arm above their head.
If the replacement is carried out for rheumatoid arthritis then often the rotator cuff will be very thin because of the disease. Under these circumstances the end result of the surgery is never quite so good because the patient will not commonly be able to lift their arm above their head. In some patients with rheumatoid arthritis the rotator cuff is completely deficient and the head of the humerus runs on the underside of the acromion. The situation is quite difficult to treat but basically the resurfacing can be adjusted to run slightly on the underside of the acromion.
In a similar situation in osteoarthritis the rotator cuff deficiency can be compensated for by using what is called a reversed shoulder, for example the Delta shoulder, however this type of shoulder replacement is generally not appropriate for patients with rheumatoid arthritis.
How is the joint replaced?
The shoulder joint is opened from the front of the shoulder using an incision which runs on average 15cm (6 inches) down the front of the shoulder. The deltoid which is the big muscle on the outside of the shoulder is retracted and the tendons of some of the small muscles are released to allow access to the front of the shoulder. When the shoulder is opened the surface of the head of the humerus comes into view. The arthritic bone surface is removed with a device that looks like a spherical cheese grater and the metal resurfacing component can then be fitted to the head or ball at the top of the humerus.
There are trial implants which are fitted to the head of the humerus to check that the shoulder joint will run nicely when the final component is in place.
After the trial the final metal component is tapped into place. The metal component is lined with a calcium containing substance similar to natural bone and the bone regrows around the component.
The resurfacing in place:
At the end of the operation the tendons which have been released are stitched and the wound is closed using skin staples for the skin.
The shoulder resurfacing which I use was devised by Mr Steve Copeland who is a shoulder surgeon in Reading. His shoulder resurfacing has the advantage of purely putting a new surface on the joint. Older types of shoulder replacement relied on a long metal stem which was either jammed into the shaft of the humerus or fitted with bone cement.
Outcomes of shoulder resurfacing
Overall shoulder resurfacing and other types of shoulder replacement are reasonably successful operations. The operation will relieve severe arthritic shoulder pain in a very satisfactory way, however the result is never really optimal if there is any damage to the rotator cuff. For this reason shoulder resurfacing and shoulder replacement are often not quite as successful as a really good quality hip replacement or elbow replacement.
Over the past fifteen years I have performed around fifty shoulder resurfacings using the Copeland resurfacing component and during this time I have also performed a small number of stemmed shoulder replacements usually when the humeral head is too destroyed for the resurfacings.
When we reviewed the results of thirty-five shoulder resurfacings which had been performed in the early to mid 1990s we found that in the long term about three quarters of them had quite good pain relief. In some of the remainder the result was slightly spoiled by either stiffness or incomplete pain relief. There were only two of the patients who still had bad shoulder pain and there were no major complications such as infection, loosening, etc. Currently one of our research fellows at the orthopaedic hospital is reviewing the results of a further twenty of my shoulder resurfacings and also resurfacings carried out by my colleague Mr Duncan Learmonth.
The main benefit of shoulder resurfacing is the relief of arthritic shoulder pain. Some patients who have a shoulder resurfacing, particularly for osteoarthritis, if they have a good rotator cuff they can forget that they have an artificial joint and they can use it easily for overhead activities such as changing light bulbs. In patients with more markedly damaged joints and in patients with rheumatoid arthritis often the joint is fairly pain-free for day to day use but it cannot be lifted up above shoulder height.
The shoulder resurfacing is a relatively straightforward procedure from the surgical point of view but it can have occasional serious complications. The complication we worry about most is infection. If the artificial shoulder was to become infected it would certainly have to be operated on again and the patient could be left every bit as bad as they were to start off with, particularly if the infection cannot be fully eliminated. The rate of infection in my shoulder resurfacings at the Royal Orthopaedic Hospital is currently zero. Having performed a little over fifty of the procedure there may be an element of luck here. I would expect that the overall risk of infection is probably around 1-2%. The risk of infection in joint replacements is higher in patients with rheumatoid arthritis, diabetes, obesity and other medical problems. Bearing in mind these factors and looking at results from other series of shoulder resurfacings and other joint replacements I would say that the overall risk was probably around 2%.
There are risks of damage to nerves and blood vessels around the shoulder. Damage to blood vessels at the shoulder is a rare but serious complication. Damage to the nerves around the shoulder is probably a little more common. There is a large bundle of nerves just next to the shoulder called the brachial plexus. Although we should be able to guarantee not to cut any of these nerves they can respond unpredictably to the bruising which you inevitably get following a shoulder resurfacing. I think the overall risk of some type of nerve injury causing tingling or numbness in the upper limb is probably around 1% or so.
The risk to the patient’s life from a shoulder resurfacing is very small indeed but it cannot be totally ignored. For a fit individual the risk is probably a little lower than other types of joint replacement at around 0.2% or so. Shoulder resurfacing is much less of a shock to the system than a total knee replacement and the surgery does not last quite so long. The risk is obviously higher in people with medical problems and it is probably a bit higher in patients over the age of 80. The main medical complications are heart attacks during or after the surgery and the formation of blood clots in the legs which may float off to the chest with dire consequences. The risk of this happening is reduced in high risk patients by giving the patient regular doses of Aspirin or other anticoagulants around and after the time of surgery.
The bones of the shoulder in rheumatoid are often very fragile so there are complications such as fractures at the upper end of the humerus. This can occur during surgery and there are special implants designed to cope with this situation.
Overall therefore the risk of a major complication from the surgery is probably around 2%.
Between the 80% of operations which are very successful and the 2-3% where there is some major problem, there is a group of 20% or so of patients who have a slightly suboptimal result, the procedure is not a disaster but it is spoiled by some problem, particularly difficulty in elevating the shoulder and aches and pains around the shoulder joint.
The care of the patient before and after shoulder resurfacing
Prior to your surgery it is important that you tell the treating team and the anaesthetist about any medical problems you have and you will be seen at a pre-op assessment clinic for this purpose and to have a full medical check-up.
All patients undergoing shoulder resurfacing surgery have a blood count and their biochemistry checked together with the blood inflammatory markers which are used to monitor the activity of rheumatoid arthritis and check up on infection. Some patients need their chest x-rays and ECGs done. Patients with rheumatoid arthritis need to have a neck x-ray prior to surgery as rheumatoid arthritis can cause instability in the cervical spine. Patients can prepare themselves for surgery by understanding what is going to happen and by keeping as physically fit as possible prior to the surgery, you should therefore do your muscle exercises as much as you can within the limits of the fact that your shoulder is obviously painful. If you have rheumatoid arthritis your medical management should be optimised by the rheumatologist and the rheumatologist may also treat you with medications such as calcium and bisphosphonates to improve your bone density.
If you are a smoker you should stop. Smoking certainly increases the risk of a surgical complication following any procedure and total joint replacement is more likely to be problematic in a smoker.
Loosening in shoulder resurfacings is probably more common in people who have to use crutches or walking sticks because of lower limb problems, although this is not such a big problem as it is with elbow replacements. It is therefore routine that if you have a significant hip or knee problem this should be sorted out before any upper limb surgery is performed. Most patients come to this conclusion themselves anyway because the pain and disability caused by significant arthritis in the hip and knee is a more major problem for day to day life than the shoulder.
Progress after shoulder resurfacing
Following the surgery the anaesthetist will have placed a drip in your arm. You may have a nerve block catheter which is used to numb the pain in your arm so that you do not have to have such a strong general anaesthetic. Shoulder resurfacing surgery is almost always carried out under a general anaesthetic. Although it is possible to numb the shoulder using nerve blocks most patients with rheumatoid arthritis find it difficult to lie down in comfort for a long period and also the nerve blocks sometimes do not completely anaesthetise the shoulder.
Following the surgery your skin will be closed with metal clips and there are no drains used. You will have a stick-on dressing on the skin and the shoulder is supported either in a grey forearm sling or alternatively a pink elasticated strap around your wrist. Either system is fine. I recommend whichever is the most comfortable for the patient. Following the surgery the patient’s shoulder is mobilised initially with help from the physiotherapist.
The physiotherapist initially will encourage you to move your shoulder forward and backwards under its own steam. You should be able to bend the shoulder a small distance at a fairly early stage. The physiotherapist can encourage you to bend the forearm upwards towards 90 degrees by pushing on the back of the elbow. This procedure does not put too much strain on either the capsule of the joint or the muscular repair. The physiotherapist can also encourage you to internally rotate your shoulder, that is, get your hand initially over your tummy and eventually to your back. Turning the shoulder outwards tends to put a little more stress on the repair of the front the capsule so it is a mistake to twist the forearm forceably outwards. It is a mistake to try to lift very heavy weights at an early stage because this puts strain on the repair of the tendons attached to the corocoid at the front of the shoulder, however you can passively lift up the arm using a pulley system which your physiotherapist can instigate as soon as the shoulder starts to settle down.
Most patients will leave hospital after about three days if they are local patients with some help at home and possibly a little longer if they come from a long distance or they live alone.
Patients with rheumatoid arthritis may have difficulties caused by other joint problems. If you have pain in the other shoulder or the elbows prior to the surgery, if you let us know we can inject these joints whilst you are under the anaesthetic which often helps with post-operative progress.
The clips are removed from the skin at about fourteen days. By this time you should be mobile around your house and starting to exercise the shoulder under your own steam. After two weeks you can normally remove whatever sling or support you have been wearing.
To get back to driving your car, you will normally need to wait a good six weeks or so. Obviously if you have an automatic life is a little simpler, particularly if it was your left shoulder which was resurfaced. You will probably have a clear idea in your mind when the elbow is strong enough to control your car. The best thing is to take your car to a quiet cul-de-sac and make sure that you have good control of it and you can do an emergency stop before you set off down the M6.
Shoulder resurfacing, in common with other joint replacements, is a significant operation. Most of the time it is quite successful in terms of pain relief although the surgery may not restore the shoulder completely to normal. The chances of success are increased by careful attention to detail both from the surgeon, other members of the team and the patient.