biostudies-literatureUnknown10(4)Ton DA<h4>Objectives</h4>Although joint swelling is traditionally interpreted as synovitis, recent imaging studies showed that there is also inflammation of tenosynovium and intermetatarsal bursae in the forefoot. We aimed to increase our understanding of differences and similarities regarding forefoot involvement between ACPA-positive and ACPA-negative rheumatoid arthritis (RA) at diagnosis. Therefore, we (1) compared metatarsophalangeal (MTP) joint counts, walking disabilities and inflamed tissues between ACPA groups and (2) studied associations of joint swelling/tenderness and walking disabilities with underlying inflamed tissues within ACPA groups.<h4>Methods</h4>171 ACPA-positive and 203 ACPA-negative consecutively diagnosed patients with RA had a physical joint examination (swollen joint cRMD opene004722https://www.ebi.ac.uk/biostudies/studies/S-EPMC11448120biostudies-literatureForefoot inflammation in recent-onset ACPA-positive and ACPA-negative RA: clinically similar, but different in underlying inflamed tissues.PMC11448120van der Helm-van Mil AHMvan Dijk BTTon DAvan Steenbergen HWfalseForefoot inflammation in recent-onset ACPA-positive and ACPA-negative RA: clinically similar, but different in underlying inflamed tissues.<h4>Objectives</h4>Although joint swelling is traditionally interpreted as synovitis, recent imaging studies showed that there is also inflammation of tenosynovium and intermetatarsal bursae in the forefoot. We aimed to increase our understanding of differences and similarities regarding forefoot involvement between ACPA-positive and ACPA-negative rheumatoid arthritis (RA) at diagnosis. Therefore, we (1) compared metatarsophalangeal (MTP) joint counts, walking disabilities and inflamed tissues between ACPA groups and (2) studied associations of joint swelling/tenderness and walking disabilities with underlying inflamed tissues within ACPA groups.<h4>Methods</h4>171 ACPA-positive and 203 ACPA-negative consecutively diagnosed patients with RA had a physical joint examination (swollen joint c2024-01-01T00:00:00Z2024 Oct2025-04-04T01:54:15.597Z2025-04-04T01:54:15.597ZS-EPMC114481203935792710.1136/rmdopen-2024-004722