Osteoarthritis (OA) is a principal cause of disability and a more massive public health problem in the United States.
In middle-aged people with mild radiographic osteoarthritis (OA),
structural features changes do occur a little over a year, irrespective of patient’s weight loss status.
Osteoarthritis (OA) is a principal cause of disability and a
more massive public health problem in the United States. Although, no
definitive intervention exists to decrease the progression of OA, bariatric
surgery in patients with severe obesity is known to provide the improvement in
OA symptoms. Also, it reduces the pain, cartilage loss and exerts beneficial
effects on cartilage composition. The
mean durable decrease in knee pain severity scores for all such patients is
approximately 50%, with some patients experiencing remission of pain. Bariatric
surgery may develop a model of an effective treatment for chronic knee pain.
Previous MRI-based studies proposed that two intra-articular
structural features are associated with knee pain and its severity, synovitis
and bone marrow lesions (BML). Further, studies have suggested that a reduction
in synovial thickening or the volume of BML is associated with a decrease in
knee pain severity.
Rationale behind the research:
No studies of patients with knee pain undergoing bariatric surgery
investigated if pain improvement was accompanied by a decrease in synovial
thickening or BML size.
Therefore, in the present study the authors assessed whether those
experiencing substantial weight loss had changes in innervated knee structures
or in cartilage.
Objective:
To confirm the effect of substantial weight loss on the structures linked with knee pain and in cartilage.
Study outcome measures:
Time period: baseline,
and 1-year follow-up
Study Outcomes:
This study showed that neither the anatomic structures in the knee
that is innervated and possible sources of pain in OA (i.e., BML and synovitis)
nor cartilage changed significantly at a time when subjects were experiencing
both weight loss and knee pain reduction. Moreover, except for the aMT, aLT,
and cLT cartilage subregions, thickness loss or gain measured quantitatively
were not associated with weight loss of >20% or with percent weight change
when measured on a continuous scale.
In general, a little effect of weight loss on structural features
of OA was found in this study. One explanation could be that the sample size
was small and that failure to find an effect of weight loss on BML, synovitis,
cartilage damage and cartilage thickness loss represents a type 2 error. It may
not be the case as the majority of knees in both weight loss groups (i.e.,
>20% vs. <20%) showed no change at all in structural findings. Further,
the confidence bounds around the estimates were narrow, so that the mean change
in BML could not have exceeded the upper 95% confidence bound of 0.2 (for a 0e3
score); for synovitis, 0.09 (0e3 score); for cartilage damage, 0.15 (a 0e9
score). For cartilage thickness measures, 95% confidence bounds were even
narrower given the nearly universal absence of change over a 1-year period.
Further, the usually marked reduction in knee pain after massive weight loss
was reported. Even when the analyses were limited to knees with radiographic
OA, the amount of change seen was minimal. There were very few patients with
grade three disease to examine this subset in the present study. While this
study report that weight loss led to a slight thinning of cartilage in two
sub-regions, the aMT, and aLT, these are not major sub-regions affected by
disease. Thus, the conclusiveness of these findings remain uncertain. Many sub-regions were examined, and many
analyses performed, making it possible, as expected, given multiple testing to
find positive results by chance. It is noted that in early OA, cartilage swelling,
and thickening may be the first pathologic changes of the disease and it is
possible that these subregions were swollen or edematous before the weight loss
occurred and that the thinning represents a return to a non-edematous state.
The finding from this study on the relationship between weight loss and BML is consistent with a previous study by Gudbergsen et al. that reported that changes in BML score during a 16-week weight loss program were not affected by changes in weight.
In conclusion, rapid reduction in pain with marked
weight loss was seen but was not accompanied by the structural change in
cartilage.
The results of the current study revealed that in the middle-aged
patients, bariatric surgery was not associated with any effects on the
structural changes in the bone.
Osteoarthritis and Cartilage
Changes in the structural features of osteoarthritis in a year of weight loss
S.R.Jafarzadeh et al.
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