|►Rotator cuff tear|
|►Advice sheet on shoulder replacement|
|►Advice sheet on injection|
|►Advice sheet on decompression|
|►Advice sheet on stabilization|
|►Advice sheet on cuff repair|
Replacement surgery is indicated in those patients who have severe arthritis of the glenohumeral joint in which the joint surface has been destroyed. It is also sometimes indicated in patients who have severe damage to their rotator cuff; in these patients a 'reverse geometry' prosthesis must be used. These patients will have:
Persistent pain requiring regular analgesia
Severe limitation of function
Will normally be older than 60 years. If possible surgery in younger patients is avoided because of the increased risk of wear and loosening of the prosthesis.
Results of surgery
Shoulder replacement is normally very successful at relieving pain, with over 90% of patients noting very marked improvement both of pain at rest and on movement.
Most patients will have considerable stiffness prior to surgery. In some cases this will resolve after surgery, but this improvement is unpredictable. Some patients may gain no improvement in range of movement, but the relief of pain will normally make the shoulder more functional.
One can expect that a shoulder replacement will last at least 10 years in 90% of cases.
What are the risks?
There are obviously risks associated with any type of surgery. The important risks are as follows:
Risks associated with all surgery
- Cardiovascular problems: Heart attack and stroke can occasionally be caused by anaesthesia and surgery. The risks of this complication is normally exceedingly small in healthy individuals. The risk may be greater if you have pre-existing disease, in which case your anaesthetist / surgeon will discuss this with you.
- Thromboembolism: Blood clots may sometimes form in the veins of your legs, a condition known as 'deep vein thrombosis.' This may cause excessive swelling of your legs and may require treatment with blood thinning drugs. Extremely rarely the clot may become detached and travel to the lungs; this is a potentially fatal complication known as a 'pulmonary embolus.' There are some conditions in which the risk of thromboembolism is increased (e.g. patients on the contraceptive pill or HRT), in which case you may be given medication to reduce the risk.
- Infection: Infection can complicate any surgery. It may be possible to treat this with antibiotics alone, but more commonly further surgery and removal of the replacement is necessary. The chance of this occurring is approximately 1%.
Risks associated with shoulder replacement
- Dislocation: The risk of dislocation is low (<5%). If it does occur then an anaesthetic may be required to reduce the prosthesis. Very rarely revision surgery may be required.
- Prosthesis wear: With time the artificial joint will wear and ultimately the prosthesis may need to be revised.
- Loosening of prosthesis: It is possible that with time the hip replacement will lose its fixation to the bone. This may be associated with deep seated infection, but often occurs without any apparent cause. The chance of this occurring increases with time; there is approximately a 5-10% chance of this occurring within the first 10 years after surgery. Thereafter the risk of loosening increases and by 15 years about 30% replacements will require revision.
Although this list of complications may appear alarming it should be remembered that replacement surgery is successful in relieving pain in over 90% patients for at least 10 years.
How does a replacement work?
There are 3 basic designs of shoulder replacement:
Surface replacement: If the articular surface is very damaged but the bony architecture remains fairly normal it is possible to cover the humeral head with a metal lining: an example is the Copeland replacement as shown in the X-ray. It is a spherical cap with a central peg which fits over the arthritic humeral head. The articular surface of the glenoid (shoulder blade) can also be lined with a plastic component, although often this is not required.
Stemmed prosthesis: If the humeral head is very damaged there may not be enough bone to allow adequate fixation of a replacement cap, in which case a stemmed prosthesis must be used. In this type of prosthesis the metal ball is attached to a stem that is inserted into the hollow shaft of the bone. As with surface replacement surgery the glenoid may be re-lined as well.
Reversed geometry: The previous 2 types of shoulder replacement rely on the rotator cuff to provide a stable fulcrum that allows elevation of the arm at the shoulder joint. When there is a complete rupture (tear) of the rotator cuff this stability is lost and it becomes impossible to raise the arm. In certain cases this may be addressed by using a 'reverse geometry' replacement in which a large metal hemisphere is attached to the shoulder blade and a cup is fixed into the shaft of the humerus. This provides a much more stable articulation and will restore the ability to get the arm up to shoulder level or a little higher; it is unusual however to regain an absolutely full range of movement.
|© J M Britton 2007|