Persistent midfoot pain linked to under-recognized prevalence of osteoarthritis: Study

UK: In individuals with persistent pain in the midfoot region but no signs of osteoarthritis (OA) on x-ray, MRI findings may suggest an under-recognized prevalence of OA, particularly in the 2nd and 3rd cuneiform-metatarsal joints, states study results published in the Arthritis Care and Research. Joint abnormalities were not strongly related to under-recognized pain or foot-related disability.

Foot pain is a relatively common and frequently encountered symptom in primary care. Osteoarthritis (OA) is likely to be one underlying cause of foot pain. Foot OA has been identified as an important contributor to the overall burden of OA, affecting 1 in 6 adults aged over 50. Midfoot OA is the most disabling form of foot OA, resulting in persistent pain, and difficulty walking and carrying out daily activities. Plain x-ray has been the base for diagnosing midfoot OA but magnetic resonance imaging (MRI) has greatly expanded the understanding of OA. MRI allows assessment of bone and soft tissue pathologies, and structural changes can be visualized before they become apparent on x-ray. MRI findings have identified a previously unrecognized prevalence of bone marrow lesions (BMLs) in people with midfoot pain but no x-ray signs of OA, yet little is known about the type and extent of MRI-detected joint changes. 

John B., University of Leeds, UK,  and colleagues conducted a cross-sectional study to compare MRI-detected structural abnormalities in people with symptomatic midfoot OA, persistent midfoot pain, and asymptomatic controls, and to explore the association between MRI features, pain, and foot-related disability.

Researchers enrolled 107 adults consisting of 50 patients with symptomatic and radiographically confirmed midfoot OA, 22 adults with persistent midfoot pain but the absence of radiographic OA, and 35 asymptomatic adults. All underwent 3T MRI of the midfoot and clinical assessment. MRIs were read for the presence and severity of abnormalities (bone marrow lesions (BMLs), subchondral cysts, osteophytes, joint space narrowing (JSN), effusion-synovitis, tenosynovitis, and enthesopathy). Pain and foot-related disability were assessed.

Key findings of the study,

• The severity of BMLs in the midfoot was greater in people with midfoot pain and no x-ray signs of OA compared to controls (p = 0.007), with a pattern of involvement in the cuneiform-metatarsal joints similar to those with midfoot OA.

• In univariable models, BMLs, JSN, and subchondral cysts were positively associated with pain (p <0.01).

• In multivariable models, MRI abnormalities were not associated with pain and disability when adjusted for covariates.

The authors conclude that structural abnormalities of OA not visible on plain-film x-rays, such as BMLs, are associated with persistent midfoot pain in people without radiographic OA, as well as symptomatic, radiographic OA.BML patterns have been found to be consistent with previously recognized sites of elevated mechanical loading. Also, Joint abnormalities are not strongly associated with pain or foot-related disability.

Reference:

John B. Arnold PhD,Jill Halstead PhD FFPM(Glas) RCPS,Carmen Martín-Hervás MD PhD,Andrew J. Grainger BM BS FRCR FRCP,Anne-Maree Keenan PhD FFPM RCPS(Glas)  First published: 19 May 2022 https://doi.org/10.1002/acr.24955