Disturbances of the knee joint caused by the adipose tissue have already been described in some cases by Johannes Müller as lipoma arborescens, and by König as lipoma solitarium. The former disease is determined by the exuberant growth of fat villi, sometimes to such an extent that they fill up the joint and cause an expansion of the capsule. Schuchardt was the first to show by his microsopic researches that these conditions had nothing to do with tuberculosis of the knee joint.
The lipoma arborescens is no real tumor like the lipoma solitarium of König, which varies from the size of a cherry to that of a walnut and is generally situated on the median side of the joint, with a pedicle reaching into the joint itself. König thinks these tumors originate in the subsynovial fat tissue, and compares them in this respect to the lipoma subperitoneal. They have been
A. HOFFA. THE INFLUENCE OF THE ADIPOSE TISSUE WITH REGARD TO THE PATHOLOGY OF THE KNEE JOINT.. JAMA. 1904;XLIII(12):795–796. doi:10.1001/jama.1904.92500120002h