Ece ZENGİN, Behlül ATALAY, İhsaniye SÜER DOĞAN
Archives of Basic and Clinical Research - 2026;8(2):135-142
Objective: To evaluate the association between infrapatellar fat pad (IPFP) maximal area, depth, and signal intensity alterations and the presence and severity of patellar chondromalacia on magnetic resonance imaging (MRI). Methods: In this single-center retrospective study, 172 knee MRI examinations with patellar chondromalacia and 78 control examinations were analyzed between January 1, 2024, and January 1, 2025. MRI scans were acquired without contrast using a 1.5-Tesla system (Ingenia Evolution, Philips Medical System, Best, the Netherlands). Alterations in IPFP maximal area, depth, and signal intensity (graded 0-3) were measured on fat-suppressed proton density-weighted images. Chondromalacia was staged using the MRI-adapted Outerbridge classification. Demographic characteristics, medial subcutaneous fat thickness, and IPFP measurements were compared between groups. Correlation analyses were performed to assess associations between IPFP metrics and chondromalacia severity. Parametric and nonparametric tests were applied; P < 0.05 was considered statistically significant. Results: Patients with chondromalacia were older than controls (50.8 +/- 10.1 vs. 38.7 +/- 12.7 years; P < 0.001) and included a higher proportion of females (P = 0.009). Medial subcutaneous fat thickness was greater in the chondromalacia group (P < 0.001). Male sex was correlated with larger maximal IPFP area and depth (P < 0.001). No significant correlation was observed between medial subcutaneous fat thickness and IPFP size. The IPFP signal intensity score was positively correlated with age (r = 0.50) and with chondromalacia grade (r = 0.377; P < 0.001 for both). IPFP maximal area and depth showed no significant association with chondromalacia grade, lesion location, or signal intensity score. Conclusion: MRI signal intensity alterations of the IPFP are strongly associated with patellar chondromalacia severity. In contrast, dimensional measurements alone (area or depth) do not reflect disease severity, highlighting the superior diagnostic value of qualitative signal assessment.
