Influence of infrapatellar fat pad size on the development and severity of chondromalacia patella

The inflammatory role of the infrapatellar fat pad (IPFP) in cartilage damage has been well-documented, yet its potential protective function as a shock absorber remains underexplored. This retrospective cohort study aimed to evaluate the relationship between the IPFP size and chondromalacia patella (CP), while also examining the effects of age, sex, and body mass index (BMI). Magnetic resonance imaging scans from 311 patients aged 40 to 65 years were retrospectively analyzed. Axial sequences classified CP severity, and sagittal sequences measured IPFP areas. CP was graded according to the International Cartilage Repair Society system, and patients were grouped into control (no CP), mild CP (grades 1-2), and severe CP (grades 3-4) categories. Demographic data, including age, sex, and BMI, were collected, and statistical analysis explored the relationships between IPFP area, CP severity, and these factors. Of the patients, 145 (46.6%) had no CP, while 166 (53.4%) had varying CP severity. Patients with CP had significantly smaller IPFP areas (6.16 ± 0.67 cm2) compared to controls (6.96 ± 0.87 cm2, P < .001). The mean IPFP area decreased progressively with increasing CP severity. After adjusting for confounders, a smaller IPFP area was significantly associated with the presence and severity of CP (P < .001). These findings provide evidence that a larger IPFP area plays a protective role in maintaining patellar cartilage integrity and mitigating CP progression, as demonstrated by a significant inverse correlation between IPFP area and CP severity, independent of age, sex, and BMI. A comprehensive, multidisciplinary approach integrating biomechanical, metabolic, and inflammatory factors is warranted to fully elucidate the role of IPFP in CP.