The relationships between patellofemoral bone remodeling, cartilage composition, and vertical loading rate: PET/MRI in isolated patellofemoral osteoarthritis

• Published in: Osteoarthritis and cartilage 2024-12, Vol.32 (12), p.1591-1600
• Main Authors: Bhattacharjee, Rupsa, Hammond, Eric, Chotigar, Ngarmsrikam, Akkaya, Zehra, Jiang, Fei, Bahroos, Emma, Han, Misung, Behr, Spencer, Bucknor, Matthew D., Souza, Richard B., Pedoia, Valentina, Majumdar, Sharmila
• Format: Article
• Language: English
• Subjects: Aged; Bone Remodeling - physiology; Cartilage, Articular - diagnostic imaging; Female; Gait; Humans; Loading-Rate; Magnetic Resonance Imaging - methods; Male; Middle Aged; Osteoarthritis; Osteoarthritis, Knee - diagnostic imaging; Osteoarthritis, Knee - physiopathology; Patello-femoral; Patellofemoral Joint - diagnostic imaging; Patellofemoral Joint - physiopathology; PET/MRI; Positron-Emission Tomography - methods; Sodium-fluoride; Weight-Bearing - physiology
• ISSN: 1063-4584; 1522-9653; 1522-9653
• DOI: 10.1016/j.joca.2024.09.001

Loading is invariably an important factor of consideration for understanding the causality flow and parallel existence of articular cartilage and subchondral bone changes. The goal of this study was to investigate the patterns of subregional 18NaF-SUV vs. T1p-T2 associations and vertical ground reaction force loading rates; in isolated patellofemoral-joint-osteoarthritis (PFJ-OA) patients. Thirty-five isolated PFJ-OA patients, with no tibiofemoral involvement, underwent simultaneous scans in a 3.0T whole-body hybrid positron emission tomography–magnetic resonance imaging scanner. MRI Whole-Organ Magnetic Resonance Imaging Scoring assessments were performed to identify/confirm isolated PFJ-OA knees from bilateral scans. T1p-T2 relaxation and SUV values were automatically computed for both trochlear and patellar cartilage and subchondral bone subregions (deep, superficial, lateral, and medial). Maximum vertical impact loading rates (Loading-RateNorm) were calculated from walking trials. Relationships were explored between SUV uptake, T1p-T2 values, and Loading-RateNorm via linear mixed-effects modeling. Significant and complex association patterns were noted between medial and lateral bone 18NaF-SUV uptakes vs. medial and lateral cartilage sub-regional T1p and T2. SUVMean and SUVMax were positively associated with deep cartilage subregional T1pand T2 values; and negatively associated with superficial cartilage subregional T1p-T2 values in both medial and lateral regions. Both medial and lateral bone 18NaF-SUVMean and SUVMax uptakes remained positively associated with the individual gait characteristics, i.e., peak vertical impact loading rates (Loading-RateNorm). Evidence of simultaneous, complementary, cross-sectional associations between T1p-T2 values and peak vertical loading rates with 18NaF-SUV, have been rare in the isolated PFJ-OA cohort. The clinical implications of such novel associations remain of utmost importance from a gait retraining perspective.