Understanding this definition becomes important when
we consider the impact of exercise on development of OA,
as osteophytes (typically the first feature identified on
radiographs) are not necessarily a deleterious finding and
may represent an effort on the part of the joint to promote
stability. They are important, however, if they represent
a source of symptoms, and yet most of the positive
evidence that suggests an association between exercise
and OA is based on the presence of self-reported OA or
radiographic osteophytes and not on symptomatic OA
(the concomitant presence of pain and radiographic
features). It is the presence of symptomatic OA that is
important clinically, not simply the radiographic identification
of osteophyte formation or self-reported OA (where
misclassification is even more problematic than the
commonly used radiographic OA definition)