Shoulder Replacement
Information to Patients Regarding Shoulder Replacement.
Note: Arthritis of the shoulder, be it
rheumatoid or osteoarthritis (wear and tear), is not a particularly
common condition and pain in and around the shoulder is not always
caused from arthritis, in fact, is much more commonly caused by
tendonopathies occurring in the shoulder. This being the
case, however, arthritis of the shoulder does occur and shoulder
replacements are regularly undertaken by Mr Nimon.
These procedures are good procedures for relief of pain and the
results tend to be very successful. However, it is not as
simple a procedure as a hip or knee replacement and the long-term
results are not quite as good as well. When arthritis does
occur in a shoulder, the shoulder replacement, be it a half
replacement called a hemi or total shoulder replacement, can
readily give improvement in symptoms which will improve patient's
quality of life. What determines whether a whole replacement
or half replacement is undertaken is based upon the diagnosis, i.e.
has the bone died off on its own or is there a tendon tear around
the shoulders that lead to arthritis in which case a half
replacement is done or is there rheumatoid arthritis or
osteoarthritis which is more likely to require total shoulder
replacement.
The shoulder is a much more unstable joint than the hip and knee
and consequently relies on good soft tissue balance and implant
positioning. When the cuff is torn, the shoulder tends to
jump or translates more in the cup and consequently a full shoulder
replacement lying on plastic in the cup, can cause it to wear more
quickly and becomes loose and will wear out quickly.
Consequently, a total shoulder replacement is not done in this
situation. Another situation where half shoulder replacement
is done is a fracture (broken shoulder). The results of
fractures not generally as good because the attachments of the
muscles to the bones have been broken off and never heal perfectly
even with surgery.
Consequently, Shoulder replacements are not always done for the
same reason and consequently the results vary.
Despite this, however, in general, elective surgery for
non-fracture situations leads to 90% successful results with
expectation of approximately 10-years before a second procedure or
revision may need to be undertaken. Surgery involves a large
incision over the front of the shoulder in an oblique fashion
separating the muscles and lifting off the (subscapularis) muscle
of the anterior aspect of the shoulder, into the shoulder
joint. The ball of the shoulder is cut, known as the humeral
head, and the proximal shoulder is reamed out or cored out to
accept a stem and a new ball. The cup is then, if needed to
be replaced, is smoothed off, and drilled to accept an implant
known as a glenoid component. We then repair the subscapularis back
to the stem and place the patient in a sling allowing no external
rotation or moving (moving the arm out to the side for a period of
three to four weeks).
After this the patient is gradually weaned from the sling,
increasing range of motion as required such that at six weeks full
motion is allowed. In a fracture situation, because of the
importance of trying to get the bits of bone with tendon attached
to them to heal to other pieces of bone, the patient is strapped to
the side for six weeks and only very gentle pendular exercises are
performed on the shoulder although the physio will show the patient
how to take the elbow and wrist out of the sling to do wrist and
elbow motion to prevent stiffness in these joints.
As with any surgical intervention, complications can
occur. These involve the general risk of an anaesthetic, but
in particular, the particular risk for the surgery. First of
all, despite the best efforts to undertake a total shoulder
replacement because of difficulties undertaken and the quality of
the bone stock found in surgery, sometimes patients have to be
prepared to accept only a hemiarthroplasty. Whilst Mr Nimon prefers
a total shoulder replacement if there are concerns about the
stability or the ability to implant the glenoid components in, a
hemiarthroplasty may be accepted. The difficulty with any
hemiarthroplasty is the risk of further glenoid erosion in years to
come. The metal balls setting into a normal shoulder socket
can wear away the socket and lead to erosion as a cause of pain and
this would be seen as a patient who does well in the short term but
come five to ten years, develops pain which requires a revision and
insertion of a glenoid component. This does not always occur
but is a disadvantage of a hemiarthroplasty. The disadvantage
of a total shoulder replacement is the glenoid component.
Despite well insertion of the glenoid into the cup, the quality of
fixation is nowhere near as good as the ball and consequently the
glenoid component is one of the first components to become loose
and play up in the total shoulder replacements and this can be a
cause of early failure. Consequently, great care is taken to
cementing the components in, because of individual patient factors
this can sometimes still lead to complications. Other factors
that can cause problems are infection. Infection is rare in a
total shoulder replacement, but does occur in 1 in 50 cases of all
arthroplasty and consequently must be taken into account.
Should an arthroplasty infection occur, the shoulder may need to be
opened up, washed out and patient placed on six months of
antibiotics. If this is caught early enough, this could lead
to a cure, however, occasionally the implant needs to be removed
for a period of time before a new implant is inserted.
The surgery does involve procedures near close to major nerves
and arteries. Much care is taken to prevent any injury to
such areas and the incidence of this is very low, however, should
it occur it could lead to weakness, numbness or a large amount of
blood loss requiring blood transfusion. Once again, this
incidence is low, but if nerve damage should occur then usually
recovers, however, it is not guaranteed.
Finally, all joint replacements have incidence of dislocation,
and shoulder replacement is not without risk. If a shoulder
replacement dislocates and may need further surgery to re-tighten
up tissues or even replace the tissues but even this does not
guarantee against further dislocations. The incidence is very
rare. Mr Nimon takes great care to avoid this happening,
however, there are multiple factors that occur, one is the patient
factors and tissue status and consequently this cannot be
guaranteed against.
Final comment regarding shoulder replacement is that surgery is
performed for pain relief. Usually by freeing up the joint
and giving pain relief, range of motion improves but it certainly
does not recover to full and one cannot expect perfect recovery of
range of motion. This is particularly prevalent when a
hemiarthroplasty is undertaken for cup or tendon tear, in which
case whilst the range of motion may improve slightly Mr Nimon does
not expect the range of motion to be significantly improved.
In general, however, patients, no matter what situation they
undergo a shoulder replacement for, are generally very happy with
the success and we can expect many years of symptom improvement to
improve quality of life.
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