Background. Pathological changes in the size and structure of Hoffa’s fat pad can cause pain in the anterior section of the knee joint. Therefore, they should be diagnosed. The objective of the paper is to improve the diagnostics of Hoffa’s fat pad disease on the basis of a detailed study of the clinical anatomy of the infrapatellar (Hoffa’s) fat pad and magnetic resonance imaging (MRI) findings in normal and pathological conditions.Materials and Methods. Protocols of 86 MRI examinations of knee joints with anterior knee pain syndrome and no clearly defined traumatic history nor positive clinical tests indicating damage to the intra-articular and periarticular elements with identified structural changes in the fat pad were selected retrospectively. The control group consisted of data from 24 examinations of asymptomatic knee joints. In all cases, the pathology was confirmed during diagnostic and therapeutic arthroscopy.Results. The MRI findings showed the normal structure of the infrapatellar fat pad, as well as pathological changes in the form of tearing, local edema, diffuse edema, synovial proliferation and fibrosis. Depending on the location and type of changes, 4 pathological syndromes were identified: “classic” Hoffa’s disease — 49 (57%) cases, infrapatellar synovial fold syndrome — 11 (13%), infrapatellar synovial fold separation syndrome — 6 (7%), and impingent syndrome of upper lateral adipose tissue — 20 (23%) cases.Conclusions. To identify a pathology, a precise synchronization of clinical and morphological changes is required. Accurate differentiation of syndromes is possible due to knowledge of the detailed anatomical and magnetic-resonance features of the fat pad in normal and pathological conditions. This allows to diagnose the cause of pain in the anterior sections of the knee joint, specify the diagnosis, and choose the optimal plan of treatment.
Schwannoma: A Rare Hoffa's Fat Pad Tumor