Observations on the growth of loose bodies in joints.

The categorization, origin, natural history, and histopathology of loose bodies in joints are well described in the literature. Clinical and basic science data have indirectly concluded that loose bodies grow over time; however, to date, there is no clearly documented published clinical example. This case report demonstrates the dramatic enlargement of 2 osteochondral loose bodies in a patient's knee over the course of a decade. The loose bodies possess a large number of viable cells; and growth appears to have occurred through encapsulation of the niduses by multiple layers of fibrocartilagenous tissue, thus confirming the findings of earlier studies.