| Orthopaedic
News: previous issues (July) |
"Synvisc' New Osteoarthritis Treatment
A new strategy for osteoarthritis treatment is the use of an injectable
hyaluronic acid compound which restores lubrication and synovial fluid
viscosity. It may also have protective effect on the cartilage matrix
and chondrocytes. "Synvisc" is a recently approved formulation
in Australia.
A significant amount of evidence exists to suggest that a beneficial
effect can be seen from the use of this substance, for several months
after treatment has stopped. The treatment regime for this substance consists
of three weekly injections in total.
Clinical trials comparing this to anti-inflammatory agents indicate the
degree of benefit to be comparable. Eleven of the twelve published placebo
controlled trials have reported a beneficial effect of the hyaluronic
acid treatment. One trial failed to show any beneficial effect. In another
controlled trial, patients over 60 yrs of age with knee osteoarthritis
was the group which benefited particularly from this line of treatment.
Two studies have shown the development of side effects or reactions to
be limited primarily to inflammation at the injection site. This is self
limiting and does not affect the efficacy of the treatment.
The existence of long term protective effects or alteration of the natural
history of osteoarthritis by these groups compounds has not yet been proven
clinically in humans. However animal studies show promising results. Symptomatic
improvement however, does seem to be predictable.
"Synvisc" has been shown to be superior to continuous NSAID
therapy and can delay the need for knee replacement in up to one third
of patients. Cost effectiveness of this therapy versus other treatments,
including the costs of treating side effects also needs to be evaluated.
The cost of a course of "Synvisc" is approximately $450.
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Unicompartmental knee resurfacing update
At the recent American Academy of Orthopaedic Surgeons meeting in Anaheim,
California the principle of unicompartmental resurfacing was endorsed
by two papers presented at the Knee Society meeting. Berger, et al presented
sixty-two consecutive patients followed from six to ten years with excellent
results. Only one patient required revision during this period to a total
knee replacement.
In another study, Callaghan, et al performed 140 consecutive unicompartmental
replacements in 103 patients with a minimum 15 yr follow up. Only 6 knees
required revision during this period.
These two papers further confirm the work of Dr J Repicci and the Oxford
group. It is a procedure that, while not applicable to all patients with
osteoarthritis does have a significant role to play. Particularly as it
is performed as a minimally invasive procedure in a short stay hospital
admission, the decreased morbidity and more rapid recovery warrant its
inclusion in the treatment options.
In my experience, the speed of recovery and extremely low complication
rate make this a better option than an osteotomy, and limit total knee
replacement surgery to those patients who have inflammatory joint disease,
multi-compartment degenerative changes or marked knee stiffness. The remainder,
with primarily unicompartmental degenerative changes and especially if
medial, may benefit from a unicompartmental resurfacing procedure.
It is the combination of a minimally invasive surgical approach with
excellent pain control which has allowed this procedure to be changed,
from one with significant postoperative disability, to one where a discharge
from hospital may be expected the same day as surgery, or the following
day, fully weight-bearing as tolerated and a rapid return to activities
of daily living.
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Driving After Knee Replacement Surgery
Patients are often concerned about returning to driving after a knee
replacement. Pain, limitation of movement and lack of control are often
identified as being limitations in the early post operative period. However
a study has shown that patient reaction time in applying the brakes when
driving can return to that seen preoperatively as early as three weeks
after surgery. It can continue improving for up to nine weeks after surgery.
It is thought that the arthritic degeneration in the knee is what causes
some slowing of the reaction time. After surgery, this is no longer a
factor.
It would seem reasonable for patients who are progressing well to resume
driving three to six weeks postoperatively.
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