How does bunion surgery (hallux valgus) work, and which procedure is right?

Dr Franz Freuler, Specialist in Orthopaedic Surgery FMH, inventor of the Hall-U-Sana® toe CPM device · U-Sana Medical AG · 27 October 2026

What is a bunion (hallux valgus), and how do you recognise it?

With hallux valgus, the bunion, the big toe drifts outwards towards the small toes at the big toe joint (first metatarsophalangeal joint), while the first metatarsal bone moves inwards. Its head sticks out on the inner edge of the foot and forms the bunion. So it is not extra bone but the displaced joint itself. Over time, shrunken ligaments and capsule fix the deformity, and the altered pull of the tendons draws the toe further outwards. The cause is usually a predisposition, and tight and high-heeled shoes make it worse. In German health insurance data, the diagnosis is recorded for just under 2% of insured people, 83% of them women (Ettinger et al. 2025).

A bunion can be recognised by three things. The big toe is crooked and crowds the second toe, often lying over or under it. The bunion rubs in the shoe, becomes red and swollen, the bursa over it becomes inflamed, and calluses form. And because the big toe no longer carries weight at push-off, the small toes take over the load: pain under the ball of the foot, hammer and claw toes and, in the long run, arthritis of the big toe joint are the result. The X-ray shows how severe the deformity is, measured by two angles; there is more on this in the section on procedures.

When should you have bunion surgery?

A bunion is a deformity, not a disease that has to be operated on. The German S2e guideline on hallux valgus (2024) names as the reason for surgery a bunion that causes symptoms where non-surgical treatment has not been enough: pain and distress, limited function, pressure points and problems with shoes. As a rule of thumb, about three months of non-surgical treatment with wide shoes, insoles and exercises come before an operation is discussed. Foot surgeons do not operate for purely cosmetic reasons, that is to straighten a toe that causes no symptoms.

Is the operation worth it compared with waiting? The 2024 Cochrane review found one study with 140 participants on this: after twelve months, pain in those who had surgery was 21 points compared with 39 in those who did not, function 75 versus 66, satisfaction 80 versus 61 (scale 0 to 100, Dias et al. 2024). So the benefit is measurable, but not automatic. If you manage well with wide shoes and insoles, there is no reason to hurry; the deformity usually progresses slowly, and the operation remains an elective procedure whose timing is set by how much it affects you.

Who is bunion surgery not suitable for?

The most important contraindication is poor circulation in the legs (peripheral arterial disease), because the wound then heals poorly. A diabetic foot and early nerve damage (polyneuropathy) also argue against the operation, whereas well-controlled diabetes without damage to the blood vessels does not. Smoking increases the risk of problems with wound and bone healing. And anyone who is not prepared to accept six weeks in a post-op shoe and several months of swelling should discuss this honestly with the surgeon beforehand.

Which types of bunion surgery are there?

There are more than a hundred surgical procedures in use for bunions. What matters is the severity, measured by two angles on the X-ray: the angle between the big toe and the first metatarsal (hallux valgus angle, normally under 15 degrees) and the angle between the first and second metatarsals (intermetatarsal angle, normally under 9 degrees). The German guideline now distinguishes only two groups: mild to moderate (intermetatarsal angle up to 18 degrees, hallux valgus angle up to 40 degrees) and severe (above that). For the first group, osteotomies of the metatarsal or a minimally invasive procedure are options, for the second an osteotomy near the base of the metatarsal or a fusion of the tarsometatarsal joint. If there is also arthritis of the big toe joint, the big toe joint is fused.

Common procedures

The figures on angles, cuts and aftercare come from specialist clinics, the German Society for Foot and Ankle Surgery (GFFC) and the aftercare plans of university hospitals. The chevron osteotomy has the longest follow-up: 112 feet over a mean of 12.7 years, the function score rose from 46.5 to 88.8 points, with a single revision (Schneider et al. 2004). Scarf and chevron osteotomies do not differ in function or complications, according to an analysis of six randomised studies with 507 feet (Peng et al. 2024). What surgeons actually choose is shown by a 2026 survey of 80 Swiss foot and ankle surgeons: for a mild bunion, scarf 49%, chevron 21%, minimally invasive 15%; for a severe bunion, fusion of the big toe joint 51%, combination with Lapidus 11% (Genuth et al. 2026). Which procedure suits you depends on the angle, bone quality, age and demands, and is the surgeon’s decision. The German guideline states that a clear superiority of individual techniques cannot be shown.

Open or keyhole bunion surgery: which is better?

Minimally invasive procedures are promoted with small scars and quick recovery. The figures are more sober. A Swiss comparative study of 50 open scarf-Akin and 48 minimally invasive chevron-Akin operations over at least two years found that the scar is shorter, 1.2 versus 5 centimetres, and that upward movement increased by 10 degrees with the minimally invasive technique, with no difference in pain, function or stiffness. Revision surgery was more frequent after minimally invasive surgery, 27% versus 8%, mostly because of protruding screws, and 14% of the minimally invasive operations had to be converted to open surgery during the procedure (Frigg et al. 2019). A large series from London with 292 feet operated on minimally invasively shows good results after two years: the pain score fell from 44.5 to 9.4, the hallux valgus angle from 32.9 to 8.7 degrees (Lewis et al. 2021). The German review of 2025 sees no difference in complications between open and minimally invasive surgery; only the third generation of the minimally invasive technique corrects the angle somewhat more. The independent German patient portal of IQWiG sums up: a quicker operation and less pain in the first two weeks, but no greater success and no fewer complications. Both are good routes if the surgeon has mastered the procedure.

What happens during bunion surgery?

Depending on the procedure, the operation takes 30 to 100 minutes, on average about an hour. The anaesthetic can be a general anaesthetic, a spinal anaesthetic or a regional anaesthetic, often combined with an ankle block that keeps the foot pain-free for hours. Many operations on the big toe are done as day surgery or with one or two nights in hospital, minimally invasive corrections as a rule as day surgery. If you live alone, arrange support for the first few days.

What happens in the operating theatre, using a chevron or scarf osteotomy as an example:

1. A skin incision on the inner side of or over the big toe joint, with minimally invasive procedures two small incisions.
2. The joint capsule is opened, the bony prominence at the bunion is removed and the shortened soft tissues on the outer side are released.
3. The first metatarsal is cut, and the head or the shaft is shifted outwards until the big toe and the metatarsal are back in line.
4. The new position is secured with one or two titanium screws; if needed, the first bone of the big toe (proximal phalanx) is also straightened with a small wedge (Akin).
5. The capsule is tightened and stitched, the skin is closed, and a dressing is applied that holds the toe in the corrected position.

The German guideline recommends an X-ray check during the operation and another afterwards, taken from at least two angles. The screws usually stay in the bone; they are only removed if they cause problems, at the earliest after six to twelve months.

What does recovery after bunion surgery look like?

Aftercare varies considerably between procedures and clinics, as the German guideline also says. The table therefore gives ranges from the plans of clinics in Germany and Switzerland. Which plan applies to you is set by your surgical team.

The ranges come from the aftercare plans of the hospitals in Münster and Kassel, Bamberg Hospital, the Gelenk-Klinik Gundelfingen, the Kantonsspital Aarau and the review in the Deutsches Ärzteblatt, and the rule on shoes from the Schön Klinik. Two things appear in almost all plans: after chevron, scarf and minimally invasive procedures, the foot may bear full weight in the post-op shoe straight away, whereas after a Lapidus fusion only partial weight-bearing of 20 kilograms on crutches is allowed for six weeks. And the post-op shoe is not a rest period for the joint, only for the bone. How the shoe works and how to walk in it will be explained in a guide to the forefoot offloading shoe, coming soon.

How long will I be off work after bunion surgery?

That depends on your job and on the procedure, and the figures from clinics in Germany and Switzerland vary widely:

The review names around 4 weeks for sitting and around 12 weeks for standing work, the Gelenk-Klinik 3 to 6 weeks after an osteotomy, and the Kantonsspital Aarau 2 to 12 weeks depending on the job. So twelve weeks are normal for physical work and not a sign that recovery is going badly.

When can I drive after bunion surgery?

Do not drive yourself while you are wearing the post-op shoe: it is not safe, and this applies to the right foot and to cars with a manual gearbox. A study of 42 patients operated on the right foot measured brake reaction time and recommended a break from driving of at least six weeks (Dammerer et al. 2016). In a second study of 60 patients operated on the right foot, 85% passed the brake test after six weeks and all of them after eight weeks; those who failed had more pain and a less mobile big toe joint (McDonald et al. 2017). If the left foot was operated on and you drive an automatic, it is possible earlier, after discussing it with your surgeon. Most clinics allow driving again when you change into normal shoes, that is in week 5 to 6. When you can drive again is decided by your surgeon; in the UK, also check with your motor insurer.

What are the risks of bunion surgery?

The review in the Deutsches Ärzteblatt puts the overall complication rate across all procedures at 18.5%, most of them minor; serious complications occur in up to 5%. The most common problems are pain under the neighbouring metatarsal heads (transfer metatarsalgia), a return of the deformity (recurrence), stiffness of the big toe joint, wound healing problems and overcorrection inwards (hallux varus). Wound healing problems occur in 2 to 4%. The Geneva University Hospitals give these figures for their patients: infection under 1%, thrombosis under 1%, bone not healing (non-union) 2 to 3%, transfer metatarsalgia 5%; altered sensation in the toe usually resolves after two to three months, but a permanently numb spot at the scar is possible. A recurrence shows on the X-ray in 10 to 15%, usually without symptoms.

These are set against the success figures: about 85% of those who have the operation rate the result as good to very good, 10% as satisfactory and 5% as poor. The Gelenk-Klinik Gundelfingen reports similar figures: around 80% feel very well, 10 to 15% are better but with remaining symptoms, and 5% notice no improvement. Across all techniques, the function score improves by an average of 33.8 points.

Does the big toe joint stay stiff after surgery?

This is the risk that is talked about least. According to the literature, stiffness of the big toe joint after open correction affects 7 to 38% of patients, and the minimally invasive technique does not change this: in the Swiss comparative study, moderate stiffness occurred equally often in both groups (Frigg et al. 2019). The review states that movement of the big toe joint can remain limited for up to a year, and IQWiG that the joint is usually somewhat stiffer after the operation. The reason lies in the joint itself: even one week of immobilisation makes the joint capsule stick together and the cartilage shrink (Akeson et al. 1987). That is why, according to the German guideline, passive and active movement of the big toe joint is part of aftercare. There is evidence for the effect: 39 patients after a chevron correction were divided into two groups, and 21 of them used a motorised continuous passive motion (CPM) device for eight hours a day over 24 days from the day of surgery, in addition to physiotherapy. Their joint was more mobile at every follow-up visit, and they returned to normal shoes and stopped taking painkillers sooner (Connor et al. 1995). The study used a different device from the one described below. And physiotherapy from the fourth week raised the function score in 30 patients from 60.7 to 94.5 points after six months and restored the loading of the big toe when walking (Schuh et al. 2008 and 2009).

What do patients experience after bunion surgery?

We do not reproduce individual reports here, because the figures from studies and clinic plans are more meaningful. What people typically experience: in the first days the foot hurts, clinics give paracetamol or anti-inflammatory painkillers according to plan, and the foot needs to be kept up. The wound heals completely in 8 to 12 weeks, even though the stitches come out after two weeks. Normal walking usually returns after 8 to 12 weeks. Swelling lasts longest: for up to half a year the foot tends to swell in the evening, and in the first year it swells more easily than before. After open surgery the scar is about 5 centimetres long, after minimally invasive surgery about 1 centimetre.

The gain becomes measurable over the months: in the Vienna study on aftercare, peak pressure under the big toe when walking rose from 80.7 kilopascals four weeks after the operation to 336.1 after six months, so the toe carries weight again (Schuh et al. 2008). The season makes no medical difference; in summer the post-op shoe is less of a nuisance, in winter the swelling in tight, closed shoes is more of a nuisance. And on the question of whether the operation is worth it: 85% good to very good, 5% poor, that is the honest range. In studies, satisfaction does not depend on the technique chosen but on how severe the symptoms were beforehand: the greater the limitation, the greater the gain.

Conclusion

Bunion surgery is a planned, elective procedure with good prospects of success when pain and problems with shoes dominate daily life and non-surgical treatment has been exhausted. Chevron, scarf, minimally invasive or Lapidus: the choice depends on the angle and on the surgeon, and no technique has been shown to be better than another. What you have in your own hands comes afterwards: wear the post-op shoe consistently, move the big toe joint early, and wait with driving and sport until your surgeon gives the go-ahead. Then what remains of the operation is a straight, weight-bearing and mobile toe.

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