Revision Total Knee Replacement
Although the failure rate per annum is low, knee replacements
do not last forever. There are two main reasons to revise a knee
replacement. The first, and most common, is infection, which can
cause early loosening of the TKR. This usually occurs in the first
couple of years after the initial operation and is often due to
an infection at the time of the initial surgery.
The other main reason for TKR failure is the non-infective loosening
of the knee replacement. This generally occurs several years after
initial operation and can be due to a mechanical failure of the
knee replacement. In some early knee replacement designs, the plastic
part of the tibial component became worn and fragmented after 8-10
years. Newer designs have considerably better durability but, eventually,
even these will show signs of wear.
What happens in Surgery?
The surgery involves removing the old knee replacement whilst
leaving as much of the original bone as possible. There can be
a considerable amount of bone loss, particularly if the old knee
replacement has been infected. If this is the case, it may be necessary
to complete the procedure with two operations. In the first, the
old knee replacement is removed and the wound is closed. Then antibiotics
are given and the infection eradicated over 4-6 weeks. The second
stage involves the insertion of the new knee replacement. This
technique minimises the risk of any further infection.
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| 1) Original Total Knee Replacement |
The Component Parts of the Revision TKR
Essentially, the revision TKR is similar to the Primary TKR. The
revision, however, needs to be able to deal with the probable
loss of bone incurred during the removal of the original knee replacement.
This is achieved by using metal blocks and stems, which attach
to the main components and compensate for any loss of bone.
The two X-ray images (1 & 2) illustrate the differences between
the original and revision knee replacements.
After a Revision Total Knee Replacement
The day after the operation your exercise regime begins. With
the aid of a physiotherapist you will get out of bed and begin
to exercise your new knee replacement. With perseverance, you should
be able to climb stairs by day 5 or 6 and go home the following
day.
You will need to continue attending physiotherapy as an outpatient.
This can be done closer to your home with one of our recommended
group of physiotherapists.
For most people it will take around 6-8 weeks to be walking reasonably.
After six months you should be able to walk well without pain,
climb stairs (leading with your operated leg) and be capable of
a range of movement with your new knee from 0 degrees to at least
90 degrees.
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| 2) Revision Total Knee Replacement |
What can I do with my new knee?
The outcome of a revision TKR is generally not as good as that
of a primary knee replacement. The revision knee replacement will,
however, give excellent pain relief and as good a range of movement
as a primary TKR. You will be able to walk without pain and
climb stairs although you may need a stick to walk longer distances.
Lifespan of a Revision TKR
The lifespan of a revised TKR depends on the reasons for revision
and the complexity of the procedure. There is a better than 80%
chance that two operations for revision of an infected TKR will
result in a knee replacement that is free of infection. Longevity
of a revision knee replacement will be less than for a primary
TKR but 75-80% should be still functioning after 10 years. |