Objective: To develop a new technique to assess the primary lesion in early rheumatoid arthritis (RA).
Methods: Ten patients with early RA and radiographically or MRI confirmed erosions had a needle introduced into the base of the erosion under sonographic guidance. Material was then aspirated from this site.
Results: The procedure was well tolerated with no complications. Small samples of necrotic bone and tissue were obtained in five out of 10 cases. In one case, a distinctive population of pleomorphic CD34 + cells with characteristics of bone marrow progenitors was isolated. Tissue invading bone with a characteristic appearance of pannus was not seen.
Conclusion: A new method of sampling the earliest lesion in RA is described. The findings raise questions about the nature of bone damage in early RA.