Introduction Hoffa’s disease (or Hoffa’s fat pad syndrome) is characterised by an impingement between the patellofemoral or femorotibial joints due to edematous changes in the infrapatellar fat pad, causing chronic anterior knee pain.1 There is no consensus on the pathogenesis, clinical definition, or treatment of Hoffa’s fat pad syndrome. This is reflected by the synonymous use of the terms patellofemoral pain syndrome, liposynovitis prepatellaris, anterior knee pain syndrome, and Hoffa’s syndrome to describe similar symptoms.2,3 Hoffa’s fat pad disease usually occurs in young active patients participating in activities involving repetitive microtrauma to the knee joint. There are no specific radiographic findings associated with the disease.
We report a middle aged patient who presented with a 6-month anterior knee pain and limited knee extension, without any trauma history.
Case report A 42-year-old middle-aged recreationel woman athlete presented with a 6-month history of mild pain on the anterior part of his right knee. Physical examination showed moderate swelling and restricted motion of the knee. Radiographs of the right knee revealed an increase in density in the infrapatellar fat pad (Hoffa’s fat pad). Sagittal T1-weighted MRI showed hypointensity in the enlarged infrapatellar fat pad (Figure 1) Sagittal and axial T2-weighted MRI revealed hyperintensity at the same localisation (Figure 2a–2b) minimal joint effusion with meniscus degeneration. The findings were suitable with inflammation of the infrapatellar fat pad. The diagnosis was made as Hoffa’s disease with the MRI evaluation.The patient was consulted for the exact diagnosis and a probable operation to the orthopaedic clinic,but the patient did not admit the biopsi fort he exact diagnosis. And also, the pain of the patient was decreased with the physical therapy.
Discussion Although the precise function of the infrapatellar fat pad is still unknown, the structure has clinical importance as the location of various tumour and tumour-like abnormalities such as para-articular chondroma or osteochondroma, Hoffa’s disease, focal pigmented villo-nodular synovitis, synovial chondromatosis, lipoma, haemangioma, ganglion cysts and chondrosarcoma.4 Hoffa’s disease is an obscure cause of anterior knee pain resulting from impingement and inflammation of the infrapatellar fat pad due to acute or chronic repetitive microtrauma.5 While inflammation is prominent during the acute phase of the disease, impingement due to fibrosis and scar tissue of the infrapatellar fat pad plays a major role in the chronic phase.6Fibrous tissue may be transformed into fibrocartilaginous tissue and it may ossify. Hoffa’s disease should be considered in the differential diagnosis of anterior knee pain.
Hoffa A. The influence of the adipose tissue with regard to the pathology of the knee joint. J Am Med Assoc 1904;43:795–6.
Bohnsack M, Hurschler C, Demirtafl T, Ruhmann O, Stukenborg-Colsman C, Wirth CJ. Infrapatellar fat pad pressure and volume changes of the anterior compartment during knee motion: possible clinical consequences to the anterior knee pain syndrome. Knee Surg Sports TraumatolArthrosc 2005;13:135–41.
Emad Y, Ragab Y. Liposynovitis prepatellaris in athletic runner (Hoffa’s syndrome): case report and review of the literature. Clin Rheumatol 2007;26:1201–3.
Sakai H, Tamai K, Iwamoto A, et al. Para-articular chondroma and osteochondroma of the infrapatellar fat pad: a report of three cases. Int Orthop 1999;23:114–17.
Hoffa A. Influence of adipose tissue with regard to the pathology of the knee joint. JAMA 1904;43:795–6.
Turhan E, Doral MN, Atay AÖ, et al. A giant extrasynovial osteochondroma in the infrapatellar fat pad: end stage Hoffa’s disease. Arch Orthop Trauma Surg 2008;128:515–19.
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