Morphometric characteristics of the prefemoral fat pad of the knee on MRI: a study in a healthy population.

BACKGROUND: The prefemoral fat pad (PFP) is located anterior to the distal femur and adjacent to the patellofemoral joint. While the infrapatellar fat pad (IFP) has been extensively studied, morphometric data on the PFP are scarce. The purpose of this study was to characterize the morphology of the PFP on MRI and to evaluate its relationship to adjacent osseous and soft tissue structures. MATERIALS AND METHODS: Twenty healthy volunteers were prospectively enrolled, and MRI examinations of 38 knees from 19 participants were analysed. Volumes of the PFP, IFP, and suprapatellar fat pad (SFP) were measured using manual segmentation. Additional morphometric parameters included body height, weight, BMI, age, numerous femoral and tibial osseous dimensions, the Insall-Salvati ratio, and the suprapatellar axial PFP area (SAPA). Correlation and regression analyses were performed to identify predictors and surrogate measures of PFP volume. RESULTS: Mean PFP and IFP volume were comparable. PFP volume showed significant correlations with selected osseous parameters of the distal femur and proximal tibia. IFP volume and SAPA demonstrated a strong correlation with PFP volume and emerged as surrogate parameters. No significant relationship was found between PFP volume and patellar height as assessed by the Insall-Salvati ratio. CONCLUSIONS: In healthy adults, the PFP is similar in size to the IFP and shows consistent morphometric relationships with adjacent structures. SAPA may represent a simplified, time-efficient candidate surrogate measure that showed a strong association with total PFP volume in this healthy cohort; further validation in larger and symptomatic populations is required before it can substitute for complete volumetric segmentation in clinical practice. These findings provide baseline morphometric data for future studies investigating pathological alterations of the PFP.