What Causes Bunions (Hallux Valgus), and Can You Stop Them Getting Worse?
A bunion forms when the big toe joint drifts out of line. This pushes a bony bump out to the side of the foot. Genes, the way your foot works and your shoes all play a part. A bunion cannot be reversed without surgery. But knowing your alignment can help you slow it down and manage the pain.
Key points
- A bunion (hallux valgus) is a shift in the big toe joint that gets worse over time. It is not just a bump of extra bone.
- Flat feet, overpronation and tight shoes often play a part.
- A scan taken lying down can miss how much the joint shifts under body weight.
- A standing weight-bearing x-ray shows the true position of the first metatarsal and big toe when they carry load.
- Non-surgical steps can slow it down, and a scan gives you a clear starting point.
If you have a bony bump at the base of your big toe, you probably already know what a bunion looks like. What most people do not know is that the bump is only part of the story. Hallux valgus is a change in the line of the whole first metatarsal and big toe joint. It tends to get worse over time. How fast it changes depends on how your whole foot takes your weight when you stand and walk.
How do you know if you have a bunion?
You can usually see a bunion just by looking at your foot. But the symptoms go beyond how it looks. The big toe slowly bends towards the second toe, and the joint at its base pushes outwards. Over time, the joint can become stiff, swollen and painful, especially in shoes.
Some people have a visible bump but no pain. Others find that even a bunion that looks mild causes a lot of discomfort. How it looks from the outside does not always match how much the joint has changed underneath.
What causes bunions?
Bunions develop when the first metatarsal bone slowly moves away from the second. The big toe then tilts inwards to make up for it. There is rarely one single cause. It is usually a mix of the foot shape you were born with, the way you walk and the shoes you wear.
Your body is a connected chain from your feet to your head. When the front of the foot takes weight unevenly, it changes how force travels up through the ankle, knee and hip. A bunion is not a foot problem on its own. It can change your lower limb alignment and add to pain in other places.
Why does a bunion need a standing x-ray?
A normal x-ray taken while you lie down relaxes the muscles and ligaments around the foot. This can make the joint look better lined up than it really is. When you stand, your full body weight presses through the front of the foot. Then the true gap between the first and second metatarsals can be seen.
With no weight on the foot, the front of the foot narrows. The angle between the first metatarsal and the big toe can look smaller than it really is when you walk. Surgeons and podiatrists may not get the full picture of how the bunion behaves under load.
Under weight, the arch flattens, the front of the foot spreads and the first metatarsal fans outwards. A standing image shows the position that matters: the one your foot is in every time you take a step. This gives your clinician a realistic starting point and helps them plan the right approach.
At ScanAlign, images are taken while you stand in a natural position. The EOS system uses about 90% less radiation than a standard x-ray, around ten times less. It shows the whole lower limb in one standing image. This lets your clinician see how the bunion relates to the alignment of your ankle, knee and hip above it.
Want to see how your bunion looks when it carries your weight? A standing scan shows what a lying-down scan misses.
Book a free video consultationHow can you stop bunions getting worse?
A bunion cannot be reversed without surgery. But there is good evidence that managing the things that make it worse can slow it down and reduce pain. The first step is knowing where your alignment stands right now.
Non-surgical steps that may help
- Wider shoes. Shoes with a broad toe box reduce pressure on the bump. They give the toes room to sit in a more natural position.
- Toe spacers. Silicone spacers worn between the big toe and second toe can ease discomfort. They may limit further drift during daily activities.
- Supportive insoles. If flat feet or overpronation add to the load on the front of the foot, custom orthotics may help spread pressure more evenly.
- Strengthening exercises. Exercises for the muscles around the big toe and arch can improve stability. A podiatrist or physiotherapist can guide you.
- Bunion splints. Night splints hold the toe in a straighter position. The evidence on whether they slow it down is mixed, but some people find them comfortable.
None of these steps replace surgery for a bunion that is already severe. If the joint has become very stiff or the toe is crossing over, a surgeon's opinion is usually the next step. ScanAlign does not provide treatment. But the images we produce are exactly what surgeons and podiatrists need to plan their approach.
When is MRI a better choice? EOS shows bones, joints and alignment. If your clinician suspects soft-tissue damage, nerve irritation or inflammation inside the joint, MRI is usually the better tool. Both scans can work together to give the full picture.
Who should get a standing scan for a bunion?
A standing foot assessment is most useful when you need a clear, objective picture of your alignment before you decide what to do next.
- Your bunion is getting worse and you want a starting measurement
- A surgeon has asked for weight-bearing images before planning an operation
- You have pain in your knee, hip or back and think your foot alignment may be involved
- You want to track change over time with images you can compare
- Your main worry is soft-tissue swelling or nerve pain (MRI is likely to be more useful)
- You have sudden redness, heat and severe pain in the joint (see your doctor first to rule out gout or infection)
- You simply need wider shoes and have not yet tried non-surgical steps
Before you start treatment, or change the one you are on, it is worth getting a detailed diagnosis. Knowing whether the cause sits in your pelvis, your legs or your spine changes what will actually help.
If you are not sure, book a weight-bearing foot assessment, starting with a free video consultation from home. We will tell you whether a scan is likely to add value in your case, before you plan any trip to London.
Frequently asked questions about bunions
No. Once the bone has shifted, non-surgical steps can slow it down and manage pain, but they cannot reverse the change in structure. Surgery is the only way to bring the joint back into line.
Foot shape and joint flexibility are inherited, and these traits make bunions more likely. Having a parent with hallux valgus does not mean you will surely get one, but it does raise the risk.
Splints may help with comfort and may limit further drift during rest. But current evidence does not show they can straighten the toe for good. They work best as part of a wider care plan.
When you lie down, the muscles relax and the front of the foot narrows. A standing image shows the true alignment under body weight, which is the position your foot is in every time you walk. This gives surgeons and podiatrists a more accurate view for planning.
Yes. The EOS system uses about 90% less radiation than a standard x-ray, around ten times less. It is a very low-dose system made for standing whole-body imaging.
No. ScanAlign is a private, self-pay clinic. You can book directly yourself. We start with a free video consultation to make sure a scan is right for you.
The price for patients travelling from abroad is confirmed during the free video consultation, before you commit to anything.
It can play a part. When the big toe joint is out of line, it changes how your foot takes weight. This can change the way force travels up through the ankle, knee and hip. Pain can show up far away from where it started.
A bunion (hallux valgus) is a sideways shift of the big toe. Hallux rigidus is stiffness and arthritis of the same joint, often with bone spurs on top. They can happen together, but they are different conditions.
A specialist radiographer looks at your concern, talks through your symptoms and checks whether a standing scan would add useful information in your case. You are under no obligation to book a scan.
See your bunion under real weight
A standing scan shows what a lying-down scan misses. Start with a free video consultation from home to find out if it is right for you.
Book a free video consultationSources
- Nix S, Smith M, Vicenzino B. Prevalence of hallux valgus in the general population: a systematic review and meta-analysis. Journal of Foot and Ankle Research. 2010;3:21.
- NHS. Bunions. nhs.uk. Available at: https://www.nhs.uk/conditions/bunions/
- Illés T, Somoskeöy S. The EOS imaging system and its uses in daily orthopaedic practice. International Orthopaedics. 2012;36(7):1325-1331.
Written by Abbas Dhami (Specialist Diagnostic Radiographer)
This page is general information and not a diagnosis.
ScanAlign is the trading name of CoreMed Solutions Ltd and operates under The Harley Street Hospital's CQC licence.