Abstract: Hoffa's disease is the clinical condition characterized by anterior knee joint pain secondary to inflammation and/or impingement of the infrapatellar fat pad. The substance P positive nerve fibers rich in the infrapatellar fat pad were stimulated by the noxious stimuli,which may associated with the pain of Hoffa's disease. The relationship between Hoffa's disease and substance P positive nerve fibers in the infrapatellar fat pad was reviewed in this paper.

Key words: Hoffa's disease, infrapatellar fat pad, substance P positive nerve fibers, review