Metatarsus adductus in adults

Almost everything written about this condition is written for the parent of a baby. The adult version is a different subject, and the two halves of the evidence appear to contradict each other: the study that followed these feet for thirty-two years found essentially nobody doing badly, while roughly a third of adults arriving for bunion surgery turn out to have it. Both are true. This page explains why, and what it means if the words have just turned up in your notes.

Written by Heath. I do not have idiopathic metatarsus adductus. I have the adductus that comes as one component of clubfoot, described in my own records from infancy, so the figures here come from the published studies rather than from experience. Every one of them is cited.

The question most people arrive with

Is metatarsus adductus the same as clubfoot?

No, and the difference is a list rather than a matter of degree. Metatarsus adductus is the forefoot turning inward at the tarsometatarsal joint, with the metatarsals deviating toward the middle of the body, the hindfoot supinating through the subtalar joint, and the first ray sitting plantarflexed.4 Clubfoot has four components, taught with the acronym CAVE: cavus, adductus, varus and equinus.

Adductus is one of those four. A clubfoot also has a heel tipped inward and an ankle pointing downward, and a metatarsus adductus foot has neither. That is why the two are told apart by hand rather than by photograph, and why flexibility is the thing being tested: the classic metatarsus adductus foot moves, and the classic clubfoot resists.

Metatarsus adductusThe front of the foot turns in. The heel and ankle are broadly where they should be. Usually flexible.

ClubfootFour things at once, of which the in-turned forefoot is one. Stiff, and treated from the first weeks of life.

Why it gets confusedFrom underneath, both give the sole a bean shape. The bean is the part a parent photographs and the part a search engine matches.

Where I sit in thisMy records describe forefoot adductus in both feet from infancy, as part of clubfoot rather than instead of it. The adductus is the half of my own feet this page is about.

The four components of clubfoot → Telling a turned-in foot apart →

Thirty-two years of follow-up

What actually happens to these feet over a lifetime

There is one study that matters here more than the rest, and it is rarely quoted to patients. Thirty-one people with metatarsus adductus, forty-five affected feet, reviewed at an average of thirty-two years and six months after they first presented. One of its three authors is Ignacio Ponseti, whose casting method is the reason clubfoot treatment looks the way it does.1

Sixteen feet, never treatedThose whose deformity was passively correctable at presentation had no treatment at all. Results were good in all sixteen.1

Twenty-nine feet, castedThose that were partly flexible or rigid had serial manipulation and plaster casts. Results were good in ninety percent.1

No poor results, and no operationsAcross all forty-five feet there were no poor outcomes, and not one patient had operative correction.1

Bunions were not the storyThe authors record specifically that hallux valgus was not a common outcome in this group.1

One more detail from that paper is worth carrying, because it changes how to read an x-ray report. An obliquity of the joint between the medial cuneiform and the first metatarsal showed on films of twenty-one of the thirty-one feet examined. It also showed in four of eleven of the patients’ own normal feet on the other side.1 A finding that turns up in feet nobody would have looked at twice is a weaker finding than it sounds.

And the other half of the evidence

Why the bunion clinic tells a different story

Read the adult literature and you meet a different condition. Nearly all of it is about hallux valgus, the bunion, because that is what brings these feet to a surgeon.

29.5 percentOf 587 patients having surgery for a symptomatic bunion, that proportion had metatarsus adductus on measurement. Historically the figure reported was about 35 percent.2

33 percentA separate series of 206 bunion operations found the same thing independently, with a mean adductus angle of 24 degrees.3

About 3.5 timesThe historical estimate of how much more likely someone with a history of metatarsus adductus was to develop hallux valgus.2

Six women to one manAmong those bunion patients who had metatarsus adductus, the ratio was 1 to 6.5.2 Claw toes and hammer toes were the commonest things found alongside.2

So one body of evidence says almost everyone does fine, and another says a third of a bunion clinic has it. Both are correct, and the reason is who got counted. The thirty-two-year study followed feet forward from childhood and asked what became of them. The surgical studies start with people who already have a painful bunion and look backward. If metatarsus adductus makes a bunion somewhat more likely, it will be over-represented in that room even while most feet that have it never end up in any room at all.

The useful reading is not that one study is wrong. It is that metatarsus adductus is a shape rather than a disease, most people who have it never need anything, and the group who do need something needed it for the bunion.

Which is you?

Where the words turned up

Choose the one that matches, and get only what applies to it.

It appeared in my notes

This is the most common way adults meet the term: an incidental line on a report written for another reason. On its own it is a description of the shape of your forefoot, not a finding that requires action.

What the evidence saysAt an average of 32 years, no poor functional results in 45 feet, and no operations.1

What would change thatPain, not shape. A bunion, pain under the ball of the foot, or a lesser toe rubbing.

What not to doChase correction of a painless foot. Nobody in the long follow-up had surgery, and nobody needed it.1

Worth askingWhether the person who wrote it thinks it explains anything you actually came in with.

I was told it before bunion surgery

This is the situation the adult research is genuinely about, and there is good news in it that gets buried under the technical argument about which operation to use.

You are not unusualRoughly 30 percent of people coming to bunion surgery have measurable metatarsus adductus.2 3

The outcome findingIn 206 patients followed two years after a scarf osteotomy, having metatarsus adductus made no significant difference to pain scores, function scores or correction achieved.3

What it does changeThe planning. It is an associated deformity that complicates the management of a bunion, which is why a surgeon measures the angle before deciding.4

Worth askingWhat your metatarsus adductus angle measured, and whether it changes which procedure they have chosen.

My forefoot hurts

Pain under the ball of the foot has a name, metatarsalgia, and it is described as common in people with this foot shape, along with lesser toe problems.4

Why the shape mattersThe forefoot turning in changes where load lands, so pressure concentrates rather than spreading across the metatarsal heads.

First movesWidth across the front of the shoe, a last that does not fight the direction of your foot, and padding or an orthotic placed at the point that actually hurts.

What the literature offersA surgical algorithm for the combination of adductus, bunion, lesser toe deformity and metatarsalgia, which tells you this combination is recognized and managed together.4

Who to seeA foot and ankle specialist rather than a general clinic, because the decision turns on measurements taken from weight-bearing films.

It is my baby

Most of what you will read is aimed here, and the reassuring version is also the evidenced one. The thing that decides the path is whether the foot can be straightened by hand.

If it is passively correctableIn the long follow-up those feet had no treatment at all and every one of them turned out good, with the deformity resolving on its own.1

If it is stifferSerial manipulation and casts, which produced good results in 90 percent at 32 years.1

The hipsWorth asking about. Any congenital foot deformity raises the risk of hip dysplasia, though metatarsus adductus raises it only marginally, at 1.5 percent against 3.5 percent for clubfoot.5

The thing to establishWhether anyone has checked it is not a clubfoot, which is a different diagnosis with a different urgency.

I have clubfoot and this came up

Adductus is one of the four components of a clubfoot, so the word can appear in a clubfoot record without meaning you have a second, separate condition. It can also describe what is left over after treatment.

As a componentThe A in CAVE. Present in every clubfoot by definition, corrected along with the other three.

As residual deformityA treated clubfoot whose forefoot still turns in is described as having residual adductus, which is a different thing from a relapse.

Why it matters for shoesIt is usually the reason a treated clubfoot is wider through the midfoot than its length suggests, and the reason the outer border wears first.

Where to goResidual clubfoot deformity covers the leftover version, component by component.

Footwear

Shoes and orthotics, with the honest caveat attached

There is no trial evidence comparing footwear for metatarsus adductus in adults. What follows is mechanics rather than proof, and it is worth saying so plainly because a great deal of what is sold for this shape is sold on confidence alone.

The single thing that matters is the shape of the last, not the size on the box. A forefoot that deviates inward does not sit in a toe box that curves outward, and the mismatch is where the pressure points come from: along the outer border, across the lesser toes, and over the first joint if a bunion is forming. Width and depth across the front of the shoe do more than any insole. An orthotic, where one helps, is usually offloading a specific painful point rather than correcting anything.

Shoes and orthotics for an adult foot → Standing all day → When the two feet differ →

Metatarsus adductus in adults

Is metatarsus adductus the same as clubfoot?

No. Metatarsus adductus is the front half of the foot turning inward, with the hindfoot supinating through the subtalar joint and the first ray dropped.4 Clubfoot has four components, remembered as CAVE: cavus, adductus, varus and equinus. Adductus is one of the four. A clubfoot also has a heel turned inward and an ankle pointing down, and a metatarsus adductus foot does not. The practical difference is that a metatarsus adductus foot is usually flexible and a clubfoot is stiff, which is what a clinician is testing when they move it by hand.

What are the long-term effects of metatarsus adductus?

Far less than the internet suggests, according to the only study that followed it that far. Thirty-one patients with forty-five affected feet were reviewed at an average of thirty-two years and six months. The results were good in all sixteen feet that had never been treated at all, and in ninety percent of the twenty-nine treated with casts. There were no poor results, nobody had an operation, and hallux valgus was specifically noted as not a common outcome.1

How is metatarsus adductus treated in adults?

Usually it is not, and that is a deliberate answer rather than a dismissive one. The deformity itself is rarely what brings an adult to a clinic. What brings them is a bunion, forefoot pain or a lesser toe problem sitting on top of it, and treatment aims at the symptom.4 Shoes that fit the width of the forefoot come first, then padding or an orthotic for the pressure points. Surgery, when it happens, is usually bunion or lesser toe surgery with the adductus taken into account rather than an operation on the adductus itself.

Is metatarsus adductus a disability in adults?

Not as a diagnosis. No system decides on the name of a condition, and the long-term evidence points the other way: in the thirty-two-year follow-up there were no poor functional results in any of the forty-five feet.1 Where an adult does have real limitation it comes from what has developed alongside it, a painful bunion or forefoot pain, and it would be assessed on what the foot stops you doing rather than on the words in the notes.

What shoes are best for metatarsus adductus?

Ones built wide across the front, and the shape of the last matters more than the size. A foot whose forefoot turns inward does not fit a shoe whose toe box curves the other way, and forcing it there is how the pressure points on the outer border and across the lesser toes get made. Look for a straight or slightly inward last, depth for the toes, and a removable insole if anything is going inside. There is no trial evidence comparing shoes for this, so treat that as mechanics rather than as proof.

How rare is metatarsus adductus?

It is usually described as the most common congenital foot difference, and no single agreed prevalence figure exists for it. What is measured is the group it belongs to: in a Norwegian cohort of 60,844 births, 1.9 percent of babies had some congenital foot deformity.5 In adult clinics it turns up far more often than people expect, being present in about thirty percent of patients coming to surgery for a bunion.2 3

Can metatarsus adductus affect walking?

In childhood it can produce an in-toed walk, which is what most parents notice, and that usually settles. In adulthood the walking itself is rarely the complaint. What the shape changes is where the pressure lands, which shows up as pain under the ball of the foot or along the outer border and as the outside edge of shoes wearing out first, rather than as a limp.

Does metatarsus adductus mean my baby needs a hip scan?

It is worth asking, and the risk is smaller than for other foot differences. In a Norwegian cohort of 60,844 children, 4.3 percent of those with any congenital foot deformity also had developmental dysplasia of the hip. Broken down by type, the risk was 6.1 percent with talipes calcaneovalgus and 3.5 percent with clubfoot, while metatarsus adductus carried only a marginally increased risk at 1.5 percent.5 The authors still concluded that a foot deformity is a true risk factor for hip dysplasia.

Sources

Where this comes from

1 Farsetti P, Weinstein SL, Ponseti IV. The long-term functional and radiographic outcomes of untreated and non-operatively treated metatarsus adductusJournal of Bone and Joint Surgery, 1994 2 Aiyer AA, et al. Prevalence of metatarsus adductus in patients undergoing hallux valgus surgeryFoot & Ankle International, 2014 3 Loh B, et al. Prevalence of metatarsus adductus in symptomatic hallux valgus and its influence on functional outcomeFoot & Ankle International, 2015 4 Varacallo M, Aiyer A. Metatarsalgia in metatarsus adductus patients: a rational approachFoot and Ankle Clinics, 2019 5 Håberg Ø, et al. Is foot deformity associated with developmental dysplasia of the hip?Bone & Joint Journal, 2020

Keep going

Next in this cluster

Residual clubfoot deformity →What is left after treatment, component by component, adductus included. Is it really clubfoot? →Three things an inward-turned newborn foot might be, and how they are told apart. Shoes for an adult foot →Width, lasts, orthotics, and what actually changes anything.