Article Text
PDF
Abstract
Background Despite distinct aetiologies of joint diseases, the osteoarthritic end-stage of primary osteoarthritis and rheumatoid arthritis are described using similar radiological features. However, primary and secondary osteoarthritis may be different at the bone-cartilage unit depending on the pathogenesis.
Objectives The main purpose was to investigate the histological differences in the bone-cartilage unit of the hip joint in patients with primary osteoarthritis and patients with secondary osteoarthritis due to rheumatoid arthritis.
Methods Femoral heads were obtained during arthroplasty from 12 patients with primary osteoarthritis and six patients with secondary osteoarthritis due to rheumatoid arthritis. Twelve femoral heads from healthy age- and sex-matched subjects were obtained post-mortem. Femoral heads were investigated, using stereological methods to provide unbiased quantitative data. The femoral head, articular cartilage, calcified cartilage, subchondral bone, and osteophytes were measured.
Volume and thickness of the bone-cartilage unit, femoral head volume and osteophyte area in healthy subjects (HS), osteoarthritis (OA) and rheumatoid arthritis (RA) patients.
Conclusion Patients with secondary osteoarthritis due to rheumatoid arthritis had thinner articular cartilage and calcified cartilage but were otherwise not significantly different from patients with primary osteoarthritis. Thus, the inflammatory joint in rheumatoid arthritis was associated with a more pronounced loss of cartilage than the degenerative joint disease in primary osteoarthritis. The thicker calcified cartilage in primary osteoarthritis has been attributed to endochondral ossification; this does not seem to be the case in rheumatoid arthritis.
Acknowledgement The authors are grateful for the technical assistance of Jette Barlach and Rita Ullerup. This work was financially supported by the Danish Rheumatism association.
Disclosure of interests Rasmus Klose-Jensen: None declared, anne Friesgaard Christensen: None declared, Louise Brøndt Hartlev: None declared, Lene Warner Thorup Boel: None declared, Mogens Berg Laursen: None declared, Kresten Krarup Keller Speakers bureau: Have received speaking fee from Pfizer, Ellen Margrethe Hauge Grant/research support from: Have received grants from Roche and Novartis, outside the submitted work., Speakers bureau: Have received personal fees from MSD, Pfizer, UCB and Sobi