What Causes Pain in Big Toe Osteoarthritis? New Research Findings
New MRI research I co-authored reveals what really drives pain in big toe osteoarthritis, and it isn't what X-rays typically look for.
RESEARCHSPORTS PODIATRY
Scott Rayment
8/9/20265 min read
Most people assume big toe osteoarthritis (first MTP joint OA) pain comes down to bone spurs and worn-away cartilage, the classic things you'd see on an X-ray. New research I co-authored, published in Seminars in Arthritis and Rheumatism, suggests that's not quite the full picture.
How This Research Came About
I reached out to La Trobe University to get involved in a research project, partly to build research experience while I was weighing up whether to pursue a PhD. You can read more about my existing clinical and sport injury experience here. Thankfully, the team already had MRI data from two separate clinical trials on first MTP joint OA, but that data hadn't yet been analysed against pain severity.
Existing research in hand, knee, and hip osteoarthritis had already established links between bone marrow lesions (BMLs), areas of signal change within the bone itself, and pain severity, changes that don't show up on a plain X-ray. Nobody had specifically tested whether the same relationship held true for the big toe joint. That's the gap this study aimed to fill.
What We Found
Using MRI data from 80 participants with first MTP joint OA, the study assessed a range of structural features: osteophytes (bone spurs), bone marrow lesions, bone cysts, effusion-synovitis (joint fluid and inflammation), cartilage loss, and joint space narrowing.
The results were genuinely striking. Bone spurs, joint space narrowing, cysts, and effusion-synovitis showed no significant association with pain severity. These are the features most commonly assessed and discussed when someone gets an X-ray for big toe OA.
What was associated with pain severity was bone marrow lesions affecting more than 66% of the first metatarsal head, and cartilage loss. Together, these two features explained 28% of the variation in pain scores, a modest but meaningful chunk, given how many factors contribute to the overall experience of pain.
Why This Matters If You Have Big Toe OA
If you've had an X-ray for big toe pain, it's likely being assessed based on visible joint space narrowing, cartilage loss, and bone spurring. This research suggests that approach may miss the features most strongly linked to how much pain someone actually experiences.
Bone marrow lesions don't show up on X-ray. They're subtle, early-stage changes that MRI can detect but plain radiographs cannot. This matters because bone spurs and visible cartilage loss tend to appear later in the disease process, while bone marrow lesions may show up earlier and could potentially help explain pain in earlier stages of OA, before more obvious structural change has occurred.
This also raises a genuine question about treatment focus. Classical approaches often target reducing dorsal impingement (the bony pinching at the top of the joint) or manage inflammation directly. This research points toward bone marrow lesions, and by extension, mechanical load on the bone itself, as a more central contributor. That opens the door to strategies aimed at reducing load through the joint (such as stiffened footwear, rocker-sole shoes, or orthotics) as potentially more relevant than purely targeting visible bone spurring. It's worth being clear that this study looked only at the relationship between structural features and pain, it didn't test treatments directly, but the findings raise meaningful questions for how management could be approached.
It's also worth noting the existing evidence in first MTP joint OA specifically has been mixed, some earlier studies found associations between structural changes and pain, others didn't. This is part of why dedicated research on this exact joint was needed rather than assuming findings from the knee or hip would simply transfer across.
An Important Nuance: Don't Panic Over a BML Finding
If you've had an MRI and it shows a bone marrow lesion, that's not necessarily something to be alarmed about. Cartilage and bone are known to have a genuine biological relationship, sometimes described as crosstalk, where changes in the bone underneath the cartilage can influence what's happening in the joint above it. Cartilage itself doesn't have pain-sensing nerve fibres, but this relationship between the two tissues appears to matter for the overall pain experience.
Bone responds to stress much like other tissue, just more slowly. It experiences load, adapts, and can become more resilient over time. A bone marrow lesion showing up on a scan reflects stress the bone is responding to, not necessarily a sign of serious or permanent damage. What it does suggest is that the bone may need the right conditions, and time, to recover and adapt.
It's also important to note this was a cross-sectional study, meaning it captured a single point in time rather than tracking people over months or years. That means it can identify an association between BMLs and pain, but it can't yet tell us whether the BML is driving the pain, the pain and load are driving the BML, or both are influenced by something else entirely. Longer-term studies are needed to work that out.
The Bigger Picture
This research is, in a lot of ways, confirmatory. Clinicians and researchers had reasonable grounds to suspect BMLs mattered for pain in this joint, based on findings in other joints. But suspecting something and actually testing it are different things, and that gap is exactly why studies like this matter. Assumption isn't evidence, even when the assumption turns out to be right.
What this tells us is that osteoarthritis in the big toe is genuinely more complex than bone spurs and cartilage wear. Multiple structures, bone, cartilage, and the relationship between them, all appear to play a role, and identifying which one contributes most to a person's actual pain experience matters for how that pain gets managed. This finding also has a practical implication for timeframes: bone marrow lesions likely take longer to resolve than something like joint effusion, which may mean treatment expectations and timelines need to reflect that.
There's also an intriguing open question this research raises rather than answers: could bone marrow lesions serve as an early marker for identifying people more likely to develop progressive OA down the track, potentially opening the door to earlier, more targeted management? That's not established yet, but it's exactly the kind of question good research is supposed to raise.
Read full paper HERE.
Results vary based on individual presentation. This article summarises published research and is intended as general education, not a diagnosis or treatment recommendation for any individual case. If you're experiencing big toe joint pain, a proper clinical assessment is the appropriate next step.
Reference: Rayment SW, Batra M, Menz HB, Munteanu SE, Erbas B, Cotchett M. Associations between MRI features and pain in first metatarsophalangeal joint osteoarthritis. Seminars in Arthritis and Rheumatism 2026;80:153029.
