Presence, location, type and size of denuded areas of subchondral bone in the knee as a function of radiographic stage of OA – data from the OA initiative

• Published in: Osteoarthritis and cartilage Vol. 18; no. 5; pp. 668 - 676
• Main Authors: Frobell, R.B., Wirth, W., Nevitt, M., Wyman, B.T., Benichou, O., Dreher, D., Davies, R.Y., Lee, J.H., Baribaud, F., Gimona, A., Hudelmaier, M., Cotofana, S., Eckstein, F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2010
• Subjects: Aged; Cartilage; Cartilage, Articular - pathology; Cohort Studies; Cross-Sectional Studies; Denuded; Female; Humans; Knee Joint - diagnostic imaging; Knee Joint - pathology; Magnetic Resonance Imaging; Male; Middle Aged; Osteoarthritis, Knee - complications; Osteoarthritis, Knee - diagnostic imaging; Osteoarthritis, Knee - pathology; Radiography; Rheumatology; Subchondral bone; Radiography; Cartilage; Magnetic resonance imaging; Subchondral bone; Denuded
• ISSN: 1063-4584; 1522-9653; 1522-9653
• DOI: 10.1016/j.joca.2009.12.011

To assess the presence, location, type and size of denuded areas of subchondral bone (dAB) in the femorotibial joint, measured quantitatively with 3 T MRI, in a large subset of OAI participants. One knee of 633 subjects (250 men, 383 women, aged 61.7 ± 9.6 y) were studied, spanning all radiographic osteoarthritis (OA) stages. dABs were determined quantitatively using segmentations of coronal FLASHwe images, representing areas where the subchondral bone was not covered by cartilage. Post hoc visual examination of segmented images determined whether dABs represented full thickness cartilage loss or internal osteophyte. 7% Of the knees were Kellgren & Lawrence (KL) grade 0, 6% grade 1, 41% grade 2, 41% grade 3, and 5% grade 4. 39% Of the participants (48% of the men and 33% of the women) displayed dABs; 61% of the dABs represented internal osteophytes. 1/47 Participants with KL grade 0 displayed ‘any’ dAB whereas 29/32 of the KL grade 4 knees were affected. Even as early as KL grade 1, 29% of the participants showed dABs. There were significant relationships of dAB with increasing KL grades ( P < 0.001) and with ipsicompartimental JSN ( P ≤ 0.001). Internal osteophytes were more frequent laterally (mainly posterior tibia and internal femur) whereas full thickness cartilage loss was more frequent medially (mainly external tibia and femur). dABs occur already at earliest stages of radiographic OA (KL grades 1 and 2) and become more common (and larger) with increasing disease severity. Almost all KL grade 4 knees exhibited dABs, with cartilage loss being more frequent than internal osteophytes.