[Hoffa's disease].

We report the case of a 40-year female patient, with no previous pathological history, presenting with right unilateral mechanical gonalgias with progressive onset, which increased climbing and going down stairs associated with hydarthrosis on clinical examination. After normal standard X ray, MRI showed a grease of hypertrophied Hoffa's grease with heterogeneous hyposignal on T1 (A), hypersignal on T2 with grease saturation (B), heterogeneously enhancing after gadolinium injection. The diagnosis of Hoffa's disease was made and the patient, after failure of a medical treatment, underwent arthroscopy for ablation of the Hoffa's grease with good evolution. Hoffa's disease, a cause poorly known of pain of the anterior compartment of the knee, is an acute or chronic inflammation of the infrapatellar adipose tissue. The physiopathologic theory speaks of repeated micro traumas resulting in inflammatory, hemorrhagic and fibrous changes of the adipose body of Hoffa; at the final stage of the disease osteochondroma occurs. MRI is the test of choice in the early forms. It shows poorly limited edematous infiltrate with hypersignal on T2 and hyposignal on T1, in a hypertrophic infrapatellar fat body. Treatment is based on general or local non-steroidal anti-inflammatory drugs, icing, and physiotherapy, associated with immobilization. In the case of failure of conservative treatment or of osteochondroma, arthroscopic resection is the treatment of choice.