Quadriceps fat pad edema: significance on magnetic resonance images of the knee

Abstract

Suprapatellar fat pad edema may be analogous to Hoffa's disease, is rare, and may be a cause of anterior knee pain. However, this finding is not infrequent and its precise association with symptoms remains unclear.

Hyperintense signal alteration in the suprapatellar fat pad on MRI is associated with degeneration of the patellofemoral joint over 48 months: data from the Osteoarthritis Initiative

“…Similarly, the other available cross-sectional studies did not find any significant associations between the presence of SPFP findings and degenerative change in the knee joint such as cartilage abnormalities, either [10,11,17]. This corresponds with our finding that baseline WORMS subscores did not differ significantly between subjects with versus those without SPFP signal alterations.…”

“…a Hyperintense signal alteration of the SPFP (arrow) and early degenerative changes of the patellar cartilage shown as hypointense signal heterogeneity (dashed arrow). b The same subject showing patellofemoral cartilage degeneration after 48 months, including an extensive subchondral bone marrow lesion (arrowheads) and a full-thickness cartilage fissure in the patella (dashed arrow) signal alteration of 54% and a prevalence of SPFP mass effect of 12% in 84 subjects without a history of knee surgery [10], which corresponds well with the numbers found by Wang et al [18], Shabshin et al [11], and Tsavalas and Karantanas [17] as well as our results, even though the prevalence of the SPFP mass effect in our population was slightly lower.…”

“…Signal characteristics of SPFPs were assessed on the IW fat-saturated 2D TSE sequence in direct comparison to signal levels of the prefemoral fat pad as a standard of reference ( Fig. 2), similar to the previously described method [10,11,18]. The signal level was considered normal if SPFP signal intensity was comparable with or lower than the prefemoral fat pad signal, and abnormal if the relative SPFP signal intensity was higher than the prefemoral fat pad.…”

“…However, data on the relevance of MRI findings of the SPFPs in OA are scarce. Previous cross-sectional studies found possible correlations between SPFP enlargement and signal alterations on fluid-sensitive MRI sequences [10], interpreted as edema, in addition to meniscal tears [11] and anterior knee pain [10,11], whereas a third study found no significant association with knee pain, patellofemoral malalignment or patellofemoral OA [17]. A fourth crosssectional study reported an association between SPFP signal alterations and mass effect with knee pain and signal alteration and bone marrow lesions, but not degenerative changes such as cartilage defects [18].…”

“…It fills the gap between the quadriceps tendon, the retropatellar cartilage, and the suprapatellar joint recess, which separates it from the prefemoral fat pad [10][11][12][13]. Like the impingement syndrome of the infrapatellar fat pad, also known as Hoffa's disease [4,5,[14][15][16], abnormalities may also be found in the SPFPs that have typical MRI findings and may be associated with clinical symptoms [10,11,17,18]. However, data on the relevance of MRI findings of the SPFPs in OA are scarce.…”