Osteoarthritic bone marrow lesions almost exclusively colocate with denuded cartilage: a 3D study using data from the Osteoarthritis Initiative

• Published in: Annals of the rheumatic diseases Vol. 75; no. 10; pp. 1852 - 1857
• Main Authors: Bowes, Michael A, McLure, Stewart Wd, Wolstenholme, Christopher Bh, Vincent, Graham R, Williams, Sophie, Grainger, Andrew, Conaghan, Philip G
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.10.2016
• Subjects: Aged; Arthritis; Body mass index; Bone marrow; Bone Marrow Diseases - diagnostic imaging; Bone Marrow Diseases - etiology; Bone Marrow Diseases - pathology; Cartilage; Cartilage (articular); Cartilage diseases; Cartilage Diseases - diagnostic imaging; Cartilage Diseases - etiology; Cartilage Diseases - pathology; Cartilage, Articular - diagnostic imaging; Cartilage, Articular - pathology; Female; Femur; Femur - diagnostic imaging; Femur - pathology; Humans; Imaging, Three-Dimensional - methods; Knee; Ligaments; Male; Middle Aged; Osteoarthritis; Osteoarthritis, Knee - complications; Osteoarthritis, Knee - pathology; Osteophytes; Spatial distribution; Tibia; Tibia - diagnostic imaging; Tibia - pathology; Trauma; United Kingdom > UK; Knee Osteoarthritis; Magnetic Resonance Imaging; Disease Activity
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/annrheumdis-2015-208407

The aetiology of bone marrow lesions (BMLs) in knee osteoarthritis (OA) is poorly understood. We employed three-dimensional (3D) active appearance modelling (AAM) to study the spatial distribution of BMLs in an OA cohort and compare this with the distribution of denuded cartilage. Participants were selected from the Osteoarthritis Initiative progressor cohort with Kellgren-Lawrence scores ≥2, medial joint space narrowing and osteophytes. OA and ligamentous BMLs and articular cartilage were manually segmented. Bone surfaces were automatically segmented by AAM. Cartilage thickness of <0.5 mm was defined as denuded and ≥0.5-1.5 mm as severely damaged. Non-quantitative assessment and 3D population maps were used for analysing the comparative position of BMLs and damaged cartilage. 88 participants were included, 45 men, mean age (SD) was 61.3 (9.9) years and mean body mass index was 31.1 (4.6) kg/m(2). 227 OA and 107 ligamentous BMLs were identified in 86.4% and 73.8% of participants; OA BMLs were larger. Denuded cartilage was predominantly confined to a central region on the medial femur and tibia, and the lateral facet of the trochlear femur. 67% of BMLs were colocated with denuded cartilage and a further 21% with severe cartilage damage. In the remaining 12%, 25/28 were associated with cartilage defects. 74% of all BMLs were directly opposing (kissing) another BML across the joint. There was an almost exclusive relationship between the location of OA BML and cartilage denudation, which itself had a clear spatial pattern. We propose that OA, ligamentous and traumatic BMLs represent a bone response to abnormal loading.