Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


MRI and Histologic Evidence for the Role of Synovitis in Bone Erosions in Erosive Osteoarthritis.

Anandarajah1,  Allen P., Paxton2,  Laura A., Giampoli3,  Ellen, Badillo3,  Kenneth, Monu3,  Johnny, Ritchlin4,  Christopher T.

Univ of Rochester Medical Ctr, Rochester, NY
University of Rochester Strong Hospital, Rochester, NY
University of Rochester Medical Ctr, Rochester, NY
University of Rochester School of Medicine and Dentistry, Rochester, NY

Background/Purpose:

Patients with erosive osteoarthritis (EOA) often develop disfiguring deformities and decline in hand function. Approximately 15% of patients with symptomatic hand OA have radiographic erosions but the relative contribution of synovitis, bone marrow edema (BME) and cartilage degradation in the development of EOA is poorly understood. To examine the role of synovitis in this disease we reviewed magnetic resonance images (MRI) and histologic data in a cohort of EOA patients.

Methods:

The medical records from a cohort of 107 EOA patients were reviewed for MRI of hands and for synovial biopsies regardless of the joint or presence of erosions. The MRIs were assessed for the presence of synovitis, BME, osteophytes, erosions, joint effusions and subchondral cysts in all proximal (PIP) (5) and the second to fourth distal (DIP) (4) joints, by 2 musculoskeletal radiologists. Tissue specimens were examined for the presence of synovitis, inflammatory cells, new bone formation and cartilage pathology.

Results:

A total of 11 patients had MRI of hands and 4 had biopsies (2 finger and 2 knees). The 11 MRIs were performed on 8 females and 3 males with a median age of 59 ± 13. All patients with MRI had evidence for progressive erosive disease on plain radiographs. A total of 54 PIPs and 44 DIPs were assessed for erosions, BME, osteophytes and subchondral cysts and 49 PIPs and 40 DIPs were assessed for synovitis and effusion. Erosions were noted in 29 PIP (54%) and 23 (53%) DIP joints, synovitis in 31 PIP (63%) and 14 DIP joints (35%), BME in 15 PIP (27%) and 11 DIP (25%) joints, osteophytes in 31 PIP (57%) and 25 DIP (57%), subchondral cysts in 25 PIP (46%) and 22 DIP (50%) joints and effusion in 4 PIP (8%) and none of the DIP joints. Erosions, synovitis and osteophytes were most frequently seen in the 3rd PIP and 5th DIP joints. Positive correlations were noted between the presence of synovitis and erosions (0.3) and the presence of BME and erosions (0.3). BME was noted more frequently near the central erosions.

A total of 4 biopsies, stained with haematoxylin and eosin, were retrieved. To date, 2 of the 4 biopsies, one from a finger with erosive disease and one from a knee joint have been analyzed and were compared with synovial biopsies from patients with rheumatoid arthritis (RA), by a pathologist. Histology revealed synovitis and new bone formation in both EOA specimens and increased inflammatory infiltrate. The frequency of inflammatory cells was however less than in patients with RA. A predominance of lymphocytes with few plasma cells were observed in EOA compared with abundant lymphoplasmacytic cell infiltrate in RA. The cartilage in EOA demonstrated central ossification, a finding not seen in RA.

Conclusion:

Synovitis was a common finding on MRI and histology in patients with EOA and along with BME was associated with the presence of erosions on MRI. Osteophytes were also seen in most of the joints in patients with EOA and along with histologic new bone formation helped distinguish EOA from RA. Synovial inflammation was associated with bone erosions in EOA and was mainly lymphocytic. Future studies will determine if synovitis precedes bone erosions or is secondary to cartilage loss.

To cite this abstract, please use the following information:
Anandarajah, Allen P., Paxton, Laura A., Giampoli, Ellen, Badillo, Kenneth, Monu, Johnny, Ritchlin, Christopher T.; MRI and Histologic Evidence for the Role of Synovitis in Bone Erosions in Erosive Osteoarthritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1075
DOI:

Abstract Supplement

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