A comparison of the joint synovitis and tenosynovitis using ultrasonography and histopathological findings in patients with rheumatoid arthritis

Background: In the treatment of rheumatoid arthritis (RA), the early diagnosis and early medical treatment via tight control have become increasingly important with the advent of biological therapy. In addition, the existence of inflammation without bone destruction on magnetic resonance imaging has been found to be significantly associated with symptoms in the patient standpoint type inspection of early RA patients. Objectives: This study was conducted to clarify the differences between the joint synovium and tendon sheath synovium, local disease activity using ultrasonography (US) and the findings on a synovial histopathological evaluation. Methods: Between March 2011 and November 2017, 663 synovectomies were surgically treated, and synovial biopsies were performed at the time of surgery. Among them, 75 tendon sheath synovia and 588 joint synovia were investigated. A total of 81 men and 582 women were examined, with an average age of 64 years old. We examined the finger in 312 cases (39 tendons, 273 joints), wrist in 323 cases (33 tendons, 290 joints) and ankle in 28 cases (3 tendons, 25 joints). There were no cases with both tendon sheath synovium and joint synovium. Just before surgery, the US probe was placed on the dorsal and palmar/plantar aspect of the joint or the tendon sheath to evaluate the activity of local synovitis. The maximum grade of power Doppler (PD) signal was determined, ranging from 0 to 3. The serum C reactive protein (CRP), matrix metalloproteinase-3 (MMP-3) and DAS28 values were also examined just before surgery. A histopathological examination of the gathered synovium at the surgical site was performed using the Rooney score (RS). Results: For the tendon sheath synovium, PD0, 14 cases; PD1, 32 cases; PD2, 19 cases and PD3, 10 cases were observed, with an average score of 1.33. For the joint synovium, PD0, 114 cases; PD1, 179 cases; PD2, 209 cases and PD3, 86 cases were observed, with an average score of 1.45. Regarding the DAS28, for the tendon sheath synovium, the average score was 3.59, and for the joint synovium, the average score was 3.61. Regarding the CRP, for the tendon sheath synovium, the average score was 0.64, and for the joint synovium, the average score was 0.66. Regarding the MMP-3, for the tendon sheath synovium, the average score was 113, and for the joint synovium, the average score was 123. There were no marked differences in the grade of PD, DAS28, CRP or MMP-3 between the synovia. The rate of synoviocytes hyperplasia did not differ between the synovia, but the rates of fibrosis and proliferating blood vessels were significantly high in the tendon sheath synovium, perivascular infiltrates of lymphocytes, focal aggregates of lymphocytes, diffuse infiltrates of lymphocytes was significantly high in joint synovium. Conclusions: There was no marked difference in the US findings and the disease activity between the tendon sheath synovium and the joint synovium. However, there were differences in the local disease activities between the synovia. These results show that the tendon sheath synovium lacked acute inflammation. Disclosure of Interest: None declared DOI: 10.1136/annrheumdis-2018-eular.1707 Citation: Ann Rheum Dis, volume 77, supplement Suppl, year 2018, page A551Session: Rheumatoid arthritis – prognosis, predictors and outcome