Relationship between MRI T2 mapping parameters and patellar ligament degeneration in patients with knee osteoarthritis

This study aims to investigate the relationship between MRI T2 mapping parameters and patellar ligament degeneration in patients with knee osteoarthritis (KOA) and evaluate its value in disease grading and prediction of clinical symptoms. A total of 149 KOA patients (284 knees) and 80 healthy subjects (141 knees) who underwent knee MRI between February 2023 and February 2024 were retrospectively analyzed. T2 mapping was performed, and the patellar ligament was divided into proximal, middle, and distal regions. Regions of interest were delineated to measure the mean (T2mean) and maximum (T2max) T2 values. Ligament degeneration was graded on a 0 to 3 scale, and KOA severity was assessed using Kellgren-Lawrence (KL) grading. Group comparisons, correlation and regression analyses, and receiver operating characteristic curve evaluation were performed to determine the diagnostic and predictive value of T2 parameters for degeneration and clinical symptoms (visual analog scale, Western Ontario and McMaster Universities Osteoarthritis Index). T2mean and T2max in all patellar ligament regions were significantly higher in KOA patients than in healthy controls (all P < .001). T2 values increased progressively with higher degeneration grades and KL grades (P < .001), and even grade 0 KOA cases showed elevated values compared with controls (P < .05). T2 parameters were positively correlated with visual analog scale and Western Ontario and McMaster Universities Osteoarthritis Index scores (r = 0.37-0.46, all P < .001). Multiple regression analysis identified T2mean as an independent predictor of pain and function. Receiver operating characteristic analysis demonstrated that proximal T2mean had the highest diagnostic performance for moderate-to-severe degeneration (area under the curve = 0.82; cutoff = 42.5 ms; sensitivity = 76%; specificity = 75%), with no significant differences among regions (P > .05). MRI T2 mapping sensitively detects microstructural degeneration of the patellar ligament in KOA. T2 values rise with increased degeneration and KL grade and correlate significantly with pain and functional limitation. Patellar ligament T2 parameters may serve as quantitative imaging biomarkers for early detection, grading, and clinical assessment of KOA.