Findings
There are many findings related to the patellofemoral compartment in this case. There is patella alta, edema at the superolateral aspect of Hoffa’s fat pad, and advanced cartilage wear of the medial patellar facet. However, the case is to highlight the prominent edema and infiltration of the prefemoral fat pad.
Diagnosis: Prefemoral Fat Pad Impingement
As was alluded to in the discussion of the findings, this is not an isolated diagnosis in this case. The overall diagnosis is patellofemoral malalignment or maltracking but what is trying to be highlighted in this case is the marked amount of edema and infiltration of the prefemoral fat. In malalignment, it is frequent to see edema of the superolateral aspect of Hoffa’s fat pad. In cases sometimes without malalignment, edema may be present of the suprapatellar or quadriceps fat pad which may be associated with frequent pain. However, this finding of marked edema of the prefemoral fat pad is fairly uncommon but may act as another area of focal pain particularly in the setting of malalignment/maltracking.
References
Dheur S, Lorthioir F. Prefemoral Fat Pad Impingement Syndrome: Correlation between Ultrasonography and Magnetic Resonance Imaging. J Belg Soc Radiol. 2024 Jun 7;108(1):61. doi: 10.5334/jbsr.3606. PMID: 38855000; PMCID: PMC11160394.
Mitchell G. Foster, Jerry Dwek, James D. Bomar, Andrew T. Pennock,
Fat Pads as a Cause of Adolescent Anterior Knee Pain. Journal of the Pediatric Orthopaedic Society of North America, Volume 3, Issue 2, May 2021, 264, ISSN 2768-2765, https://doi.org/10.55275/JPOSNA-2021-264.