The prefemoral fat pad of the knee: A large and underrecognized structure with potential clinical relevance

The prefemoral fat pad (PFP) is a widely known but in comparison to the suprapatellar and infrapatellar fat pad (IFP) a drastically underreported anatomical structure in the ventral knee. Although it is mentioned in the context of osteoarthritis and as a source of ventral knee pain, there are no reports on its anatomical characteristics and relationships.

We investigated the PFP radiologically and via dissection in 10 fresh frozen cadaveric knees. Thereby we focused on its size, anatomical relationship to neighboring structures and blood and nerve supply and compared our findings to the IFP. Samples of the PFP were also evaluated histologically and through epoxy resin plastination. Additionally, we compared its size to the size of the IFP and the extracted descriptive data of the cadavers.

We found the PFP in all knees with a mean size of 24,79 cm³, whereas the mean size of the IFP was 20,06 cm³. The PFP was directly adjacent to the femur, the articularis genus muscle and suprapatellar bursa, as well as the medial and lateral intermuscular septum and the trochlear cartilage. We found blood vessels and nerves inserting into the PFP in all cases. The size of the PFP significantly correlated with the size of the IFP and the weight of the body donor. Additionally, the PFP was larger in males than in females.

In our study the PFP was the largest of the three fat pads in the anterior knee. It always exists with a describable anatomy. The anatomical similarities between the PFP and the IFP may imply that characteristics and properties of the PFP may be similar to those of the IFP. Ultimately, the PFP's anatomical existence suggests a potential role in patellar stability and tracking.