The relationship between functional disability and MRI‐inflammation has been studied for the hands but has not been well established for the feet, even though walking‐difficulties are common. Therefore we studied whether walking‐difficulties were associated with MRI‐inflammation at metatarsophalangeal (MTP)‐joints in early arthritis patients, at diagnosis and during 24‐months follow‐up.
Five hundred thirty-two consecutive patients presenting with early arthritis reported on the presence and severity of walking‐difficulties (HAQ‐question 4a, scale 0‐3) and underwent unilateral contrast‐enhanced MRI of MTP(1‐5)‐joints at baseline. One hundred seven patients had clinical and MRI‐data at follow‐up (4‐, 12‐ and 24‐months). MRI‐inflammation (synovitis, tenosynovitis, and osteitis) was scored in line with RAMRIS. At baseline, the association of walking‐disability with MRI‐inflammation was assessed using regression. Longitudinally the association between a change in walking‐disability with a change in MRI‐inflammation was studied with linear mixed models.
At baseline, 81% of patients with walking‐disabilities had MRI‐inflammation at MTP‐joints, versus 68% without walking‐disabilities (P<0.001). Total MRI‐inflammation (i.e., the sum of tenosynovitis, synovitis, and osteitis) was associated with the severity of walking disability (β=0.023, P<0.001). Studying the MRI‐features separately, tenosynovitis, synovitis, and osteitis were all univariable associated with severity of walking‐disability (P<0.001, P<0.001, and P=0.014, respectively). Multivariable, the association was strongest for tenosynovitis. During follow‐up, a decrease in MTP‐inflammation was associated with a decrease in walking‐disability (β=0.029, P=0.001): in multivariable analyses, the only tenosynovitis was independently associated (β=0.073, P=0.049).
Of the different inflamed tissues in MTP‐joints, predominantly MRI‐detected tenosynovitis was associated with walking‐disabilities. Likewise, a reduction in tenosynovitis is related to a decrease in walking‐disabilities. This increases our understanding of the involvement of tenosynovitis in walking‐disabilities in early arthritis.