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MR scan of a knee affected by
osteoarthritic changes (coronal
T1 weighted scan). On the
left: before; on the right: after
weight reduction. The arrow
indicates bone changes
beneath the joint surface
inside the knee (medial tibial
condyle). These changes
are indicative of inflammation
in the bone. Note the
severe changes in the knee
joint with bone spurs. The
diet-based projects demonstrate
that bad knees are no
excuse for not losing weight
- and that it is never too late
to aim for improvement
through weight reduction.
The patient was a 75-year-old
woman, who took part in a
diet- based project and within
16 weeks achieved weight
reduction from a BMI of 38
down to 33.9. In our studies
based on 200 participants, a
number of scans were unchanged
following weight
loss, but where the scans did
change they were more often
than not for the better.
Objective measurements of knee status
Aside from subjective descriptions, scientific measurement techniques
provide an indication of the condition of the knee joint. Weight reduction
is thus an excellent investment, since losing one kilo in body weight means
two kilos less strain on the knee. Scans indicate that the condition of the
knee joint improves as a result of weight reduction, e.g. with reduced
fluid visible on ultrasound, while MR scans reveal that weight reduction
prevents worsening of the inflammation of the bone closest to the joint
(see figure).
Inflammation
74 OSTEOARTHRITIS OF THE KNEE AND WEIGHT LOSS
Osteoarthritis is not normally regarded as an inflammatory disease like for
example rheumatoid arthritis. Inflammation causes swelling of tissue with-
out any bacterial infection being present. But there is much to indicate that
the pain of knee osteoarthritis is actually caused by inflammation, and scans
using either MR or ultrasound detect inflammation in approx. 80% of pa-
tients with relatively severe osteoarthritis. Some patients have no symptoms
from their osteoarthritis affecting the joint, and are affected by a disease
mechanism other than inflammation, or the patients simply do not register
inflammatory symptoms. The findings of the dietary studies at the Parker
Institute indicate that inflammation may be gradually reduced as a result of
weight reduction. Given that inflammation is the primary source of pain in
osteoarthritis, it is worth considering whether the improvement achievable
from weight reduction is attributable not only to alleviation of the weight
burden on the knee but also to a reduction of the inflammation.
Medication for osteoarthritic pain
Recognition of the significance of inflammation for the pain of knee osteo-
arthritis has led to revised treatment regimens. Common medication for
inflammatory pain, NSAIDs such as ibuprofen, are widely used to alleviate
osteoarthritic pain, but since NSAIDs have side effects, they are not re-
commended for long-term pain relief.
The outlook
The treatment available for knee osteoarthritis is currently very variable in
Denmark. An improvement in the condition may be achieved from weight
reduction programmes for people with obesity, combined with physical
exercise regimes, and even if it ends in a knee replacement, these activities
will provide a better foundation for post-operative rehabilitation.
However, the first choice in pain relief during the process has not been
determined, nor whether it is significant to reduce inflammation for ex-
tended periods.
Most cases of knee osteoarthritis
are affected by inflammation,
commonly involving
the accumulation of excess
joint fluid, “water on
the knee”. Removing the fluid
relieves the symptoms, and
since the abnormal joint fluid
contains substances that degrade
tissue, fluid draining is
a form of therapy in itself.
VELUX FOUNDATION
75
AGEING RESEARCH AND OPHTHALMOLOGY