Background/Purpose: Ultrasound is used to assess disease activity in rheumatoid arthritis (RA). Gray scale (GS) ultrasound shows the synovial hypertrophy (SH) and Doppler the amount of hyperemia. SH Both with and without Doppler change during treatment in the hands– even grade 1. However, SH grade 1 without Doppler is a common finding in the feet of both RA patients and healthy controls. If low grade SH in metatarsophalangeal joints (MTPs) does not have the ability to change during treatment this should be taken in to consideration in the ultrasound evaluation of disease activity and treatment effect in the feet.
The aim was to investigate if joints with SH without Doppler activity (Doppler negative SH) in MTPs differ in ability to change during treatment with biological DMARD (bDMARD) as compared to metacarpophalangeal joints (MCPs) in RA patients.

Methods: RA patients initiating biological DMARD treatment were included. US examination was performed at baseline, 3 and 6 months using Siemens Antares US equipment with optimized Doppler settings for slow flow. Bilateral MCP 1-5 and MTP 1-5 were evaluated at each visit. SH and Doppler activity were graded from 0-3 according to the US atlas by Hammer et al. The GS score for SH in Doppler negative joints was registered for the individual joints using GS SH >1 as threshold and were compared to changes in SH score in joints with Doppler activity (Doppler positive SH) in both MCPs and MTPs. Doppler positive was defined as Doppler score ≥1.

Results: 157 patients (83.2% women, 81.3% seropositive for anti-CCP and 75.8% for rheumatoid factor) were included, with a mean (SD) age of 51.5 (13.3) years and disease duration of 9.9 (8.1) years. At baseline, 52.2% used prednisolone (mean (SD) 7.7 (4.6) mg, range 2.5-25mg). The patients had a mean (SD) baseline DAS28 of 4.5 (1.5).

1570 MTPs and 1570 MCPs were examined and of these 502 MTPs (32%) had Doppler negative SH and 245 (16%) Doppler positive SH. For MCPs, 251 (16%) had Doppler negative SH and 407(26%) Doppler positive SH. Doppler negative Grade 1 SH were more frequent in MTP than MCP joints and Doppler negative grade 3 SH was rare in MCPs (table 1). The percentage of joints exhibiting a decrease in SH was similar for both MTPs and MCPs, both for joints with Doppler negative SH and Doppler positive SH at baseline. However, adjusting for the grade of SH at baseline, joints with Doppler negative SH appeared to have a somewhat greater tendency towards change. For joints with Doppler negative SH grade 1 at baseline the tendency to change was somewhat lower for MTPs than MCPs (41% vs 63% respectively at 3 months and 43% vs 66% respectively at 6 months follow-up).

Conclusion: Most joints with Doppler negative SH had low grades of SH with the majority having a grade 1 – especially in MTPs. Doppler negative SH in MTPs and MCPs can improve during treatment and exhibit the same tendency to change. For joints with Doppler positive SH, MTPs have the same tendency to change as MCPs except that MTPs with Doppler negative grade 1 SH showed a somewhat lower tendency to change than the corresponding MCPs.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/can-synovial-hypertrophy-in-the-feet-without-doppler-change-during-treatment-results-from-a-longitudinal-study-of-rheumatoid-arthritis-patients-initiating-biological-dmard/