Lack of bone stiffness/strength contribution to osteoarthritis - evidence for primary role of cartilage damage

Objectives. This study was performed to assess osseous contributions to osteoarthritis, obviating the analysis challenges presented by confounding factors in humans and rarity of osteoarthritis in free-ranging mammals. Methods. Frequency of osteoarthritis in 21 bird species was examined and contrasted with measures of afflicted element bone stiffness and strength and compression/tension-resistant characteristics. Results. Osteoarthritis was present in the ankle of 0-16% of bird species analysed, independent of bone laminarity, cortical thickness, circularity, polarization, cross-sectional diameter, length and pneumatization. Conclusions. No correlation of frequency of osteoarthritis with parameters of bone strength and biomechanical parameters was found, suggesting that bone is only secondarily affected in osteoarthritis and that cartilage is the initial target of the disease.