Inflammation du tissu adipeux de Hoffa

Abstract

Located under the patella, the infrapatellar fat pad (IFP) or Hoffa's fat pad is the main intra-articular adipose tissue within the knee. The IFP is described as intracapsular but extrasynovial, the synovial membrane lining its posterior surface, and has substantial innervation and vascularisation. Mainly composed of adipocytes, the IFP may be infiltrated by immune cells and is a major source of pro-inflammatory factors (cytokines and adipokines). Its physiological role remains unknown, but it might act as a shock absorber and protect the surrounding tissue. Hoffa's disease is an inflammatory and fibrous hyperplasia of the IFP induced by repeated trauma and results in anterior knee pain. In chronic disease, local metaplasia within IFP may lead to the development of an osteochondroma. It could also contribute to the pathophysiology of osteoarthritis, by a procatabolic and pro-inflammatory effect on the synovial membrane, which is adjacent to the IFP. Finally, in knee OA, its inflammation may also contribute to the painful symptoms.