Session Type: Poster Session (Monday)
Session Time: 9:00AM-11:00AM
Background/Purpose: Magnetic resonance imaging (MRI) is more sensitive than physical examination in detecting inflammation. This has predominantly been studied in metacarpophalangeal-(MCP) and wrist-joints. Data on the concordance and discordance of physical examination (PE) and MRI-detected inflammation of metatarsophalangeal-(MTP)joints is scarce, which is surprising as physical examination of these joints is challenging.We aimed to study the concordance and discordance of arthritis upon PE with MRI-detected inflammation of MTP-joints. Analyses on MCP-joints were included for comparison.
Methods: 1764 MTP(2-5)-joints and 1764 MCP(2-5)-joints of 441 consecutive patients presenting with early inflammatory arthritis (36% RA, 64% other inflammatory arthritides) underwent PE of joint swelling by two independent readers, and 1.5T contrast-enhanced MRI of unilateral MTP- and MCP-joints. MRI-detected synovitis and bone marrow oedema were scored according to the RA MRI score (RAMRIS), and tenosynovitis according to Haavardsholm by two experienced readers. For a joint to be classified as PE+ swelling had to be observed by both assessors. MRI-positivity required the presence of the same MRI-inflammatory feature on joint level that was scored by both readers≥1. MRIs were further studied by two other, independent observers among whom an experienced musculoskeletal radiologist by consensus reading, to investigate the presence of contrast-enhancement of the soft tissues that was not scored according to RAMRIS guidelines. Analyses were done on joint level, joints were grouped as PE+MRI+, PE–MRI–, PE+MRI– and PE–MRI+.
Results: Physical examination of joints and MRI were concordant in 79% of MTP-joints (4% PE+MRI+, 74% PE–MRI–). For the MCP-joints this was 71% (15% and 53% respectively). Next discordance was studied. Subclinical joint inflammation (PE–MRI+) was present in 17% of MTP-joints. This was less frequent than in MCP-joints, where subclinical inflammation was present in 29% joints. Discordance in the opposite direction (PE+MRI–) was present in 5% of all MTP-joints (this was 55% of all PE+ MTPs). PE+MRI- occured less frequent at MCP-joints (3% of all MCPs were PE+MRI, which is 15% of the PE+ MCPs). Subsequently, MRI-detected contrast-enhancement of the soft tissues were studied to see if they could form an explanation for the felt arthritis. Of the PE+MRI- MTP-joints, 43% showed contrast-enhancement of the soft tissues, while in PE-MRI- joints this was 22%. Finally, to better understand this contrast-enhancement, its’ frequency was compared between RA and other inflammatory arthritides, And was 53% vs. 22% respectively (OR 4.1, 95% CI 3.3-5.0).
Conclusion: Joint examination and MRI were mostly concordant in MTP- and MCP-joints. In MTP-joints MRI-detected subclinical joint inflammation occured in 14% of joints, which was less frequent than the MCP-joints where this was 27%. Clinical joint swelling without MRI-detected joint inflammation according to RAMRIS occured more in the MTPs and was in part caused by contrast-enhancement of soft tissues; this was more frequent in RA suggesting it to be inflammatory in nature. Further detailed imaging studies are needed to further characterize its‘ nature
To cite this abstract in AMA style:Dakkak Y, Boer A, Boeters D, van der Helm-van Mil A, Reijnierse M. How Accurate Is Physical Joint Inflammation of the MTP-joints and What Can We Learn from Additional MRI on Forefoot Involvement in Early Arthritis? [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/how-accurate-is-physical-joint-inflammation-of-the-mtp-joints-and-what-can-we-learn-from-additional-mri-on-forefoot-involvement-in-early-arthritis/. Accessed December 2, 2020.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/how-accurate-is-physical-joint-inflammation-of-the-mtp-joints-and-what-can-we-learn-from-additional-mri-on-forefoot-involvement-in-early-arthritis/