Juvenile Hallux Valgus

Juvenile hallux valgus is hallux valgus that begins before skeletal maturity, usually under 14-16 years. It is distinct from congenital hallux valgus, which is present at birth, and from adult acquired hallux valgus.

Who. Girls, overwhelmingly: around 88% of Coughlin's series were female, and 40% presented at age 10 or younger.

Inheritance. Familial penetrance is high, with an autosomal dominant pattern of incomplete penetrance. Maternal transmission was recorded in 72% of patients in Coughlin's landmark cohort.

The primary deformity. Juvenile hallux valgus is often related to metatarsus primus varus, medial deviation of the first metatarsal, and the varus of the first metatarsal is the primary deformity. Ligamentous laxity allows the first ray to drift medially while the toe stays laterally.

The articular tilt. The distal metatarsal articular angle (DMAA) defines the orientation of the cartilage of the metatarsal head relative to the shaft. In juveniles the surface is often dysplastic, tilted laterally, and because the cartilage itself is tilted the joint surfaces remain parallel, or congruent, despite the valgus appearance. An elevated DMAA was present in roughly half of juvenile cases, and it is higher in early-onset and congruent-joint deformities.

Why the DMAA decides the operation. In adults the hallux valgus angle comes from subluxation of the joint; in children it often comes from the shape of the bone. Straighten the shaft by moving the head laterally without changing the tilt, and the toe points medially on a joint that is now incongruent. The toe then drifts back into valgus to make the joint congruent again, so a simple chevron that ignores the DMAA looks straight at first but leaves a joint that is incongruent and stiff, or a deformity that rapidly recurs.

What drives progression. Five risk factors are recognised:

• Female sex
• Generalised ligamentous laxity
• Anatomy: a high DMAA and metatarsus primus varus
• A tight or contracted tendo-Achilles (gastrocnemius)
• Constrictive footwear, the extrinsic factor

The physes. The first metatarsal physis is proximal, at the base, unlike the lesser metatarsals, whose physes are distal; the proximal phalanx physis is also proximal. A distal chevron or Mitchell osteotomy is therefore performed distal to the physis, though care must still be taken not to violate it while it is open. A proximal osteotomy (base wedge) or a scarf puts the physis at risk.

The case for a driver. A planovalgus, pronated foot carries the hindfoot into valgus and the forefoot into abduction, which unlocks the midtarsal joint and destabilises the medial column. The first ray becomes hypermobile, the windlass mechanism is blunted, the IMA is effectively increased, and the ground reaction force drives the first metatarsal into varus while the hallux drifts laterally. That makes a flat, pronated foot a plausible driver of the bunion and, if left uncontrolled, a plausible cause of recurrence after correction.

The counter-evidence. In Coughlin's juvenile series, moderate-to-severe pes planus occurred in only 17%, no different from the normal population, and there were no recurrences in the feet with pes planus. He concluded that pes planus did not affect the occurrence or recurrence of juvenile hallux valgus, so its causal role is debated, not established.

The practical position. Correct the heel valgus on examination and see whether the bunion improves; if it does, there is a dynamic, pronation-driven component. Orthoses that control pronation offload the medial column and may reduce that component, but they relieve symptoms rather than cure the bunion. Do not over-attribute the bunion to the flatfoot, promise that an orthosis will cure it, or let a flatfoot by itself dictate surgery.

History. Establish where the pain is: over the medial eminence, or inside the joint. Cosmesis is often the driving factor for the parents or the teenager, and expectations need to be managed firmly. Ask whether the mother has bunions, and how her surgery went.

Examination. Each step answers a question that shapes the plan:

1. Standing: assess hindfoot valgus and arch height, and perform the heel-correction test described above
2. First ray mobility: check for sagittal-plane hypermobility, and score generalised laxity with the Beighton score
3. Congruency test: reduce the hallux valgus angle to neutral and watch whether the toe rotates or the range of motion decreases. If motion is blocked when the toe is straight, the joint is congruent and the DMAA high
4. Grind: crepitus suggests arthritis, which is rare
5. Forefoot: look for metatarsus adductus, which increases the perceived deformity

Weightbearing radiographs are mandatory. They give the angles that grade the deformity and choose the osteotomy, and they show whether the physes are open:

• Hallux valgus angle (HVA): between the first metatarsal and the proximal phalanx; abnormal over 15°
• Intermetatarsal angle (IMA): between the first and second metatarsal shafts; abnormal over 9°
• DMAA: the tilt of the articular surface on the shaft, measured as below
• Physeal status: open or closed

Measuring the DMAA. Draw the axis of the first metatarsal, then a line joining the medial and lateral margins of the articular surface; the angle between them is the DMAA. Normal is under 10°, with the cartilage facing straight. An angle over 15-20° is abnormal, the cartilage facing laterally, and in juvenile hallux valgus it is often 20-30°, which is dysplastic.

Sesamoid view. Shows subluxation of the sesamoids and rotation of the metatarsal head. Crista erosion is rare in children.

Non-operative care is the gold standard. Surgery should only be considered once it has failed extensively, and before maturity it is the default:

• Education: explain the high recurrence rate after surgery
• Shoes: a wide toe box; avoid heels
• Orthotics: correct a dynamic valgus or flatfoot; they offload the medial column but do not cure the bunion
• Night splints: do not correct the structural deformity

Indications for surgery. Pain is the indication, never appearance, and correction after skeletal maturity is best:

• Severe pain interfering with daily activities and refractory to shoe modification
• Inability to wear any reasonable shoes
• Ulceration over the medial eminence, which is rare

The physis sets the options. With an open physis, the choices are growth modulation by hemiepiphysiodesis or a distal osteotomy that spares the physis. With a closed physis, adult-type osteotomies are tailored to the IMA and the DMAA.

Algorithm

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Hallux valgus interphalangeus. A distinct deformity: valgus angulation within the hallux itself, distal to the metatarsophalangeal joint at the level of the proximal phalanx and interphalangeal joint. It is measured by the hallux valgus interphalangeus angle, between the long axes of the proximal and distal phalanges, and usually arises from a trapezoidal, asymmetric proximal phalanx whose distal articular surface is tilted into valgus. It is common in juveniles and adds to the apparent lateral deviation of the toe, but a metatarsal osteotomy does nothing to it, and missing it is a common reason a great toe still looks bent after the metatarsal has been corrected.

The Akin osteotomy corrects it with a medial closing wedge of the proximal phalanx. It is an adjunct, never a stand-alone bunion operation: used alone it straightens the toe cosmetically while leaving the metatarsus primus varus, the high DMAA and any MTP subluxation uncorrected, so the bunion persists and recurs. It is added to a metatarsal procedure to fine-tune the final alignment once the IMA and DMAA have been addressed.

In Coughlin's series overcorrection into hallux varus was as common as recurrence, so quote both when consenting.

• Immobilisation: heel-wedge shoe or cast for 6 weeks
• Weightbearing: heel weightbearing is usually allowed if the osteotomy is stable
• Radiographs: at 2 weeks for position and 6 weeks for union
• Return to sport: 3-4 months

Satisfaction is generally lower than in adults, because of unrealistic cosmetic expectations and stiffness. Most return to sport, but range of motion is often permanently reduced compared with normal. Recurrence is the major long-term issue, and many require revision in adulthood.

Global epidemiology

• Strong female preponderance (around 80-90% across series) and frequent positive family history with maternal transmission. There is no implant registry for juvenile hallux valgus, so evidence rests on retrospective cohorts and small comparative series.

Society guidance, side by side There is no dedicated international guideline for juvenile hallux valgus; recommendations are extrapolated from paediatric forefoot and adult bunion consensus. Common threads across bodies:

Practice variation by resource setting

• High-resource: Weightbearing radiographs, biplanar/double osteotomies with screw fixation, and growth-modulation (hemiepiphysiodesis) for selected young patients.
• Limited-resource: Greater reliance on simple distal osteotomies with Kirschner-wire fixation and percutaneous/minimally invasive (e.g. SERI) techniques where fluoroscopy is available; emphasis on conservative management and footwear given cost and follow-up constraints.

Timing of surgery. Whether to operate before skeletal maturity for severe symptomatic deformity, or to wait and reduce recurrence, remains debated. Comparative data (Bard et al, 2024) show recurrence and complications are common regardless of physeal status, which supports a cautious, pain-driven threshold.

The optimal osteotomy. No single osteotomy is proven superior. Edmonds et al (2015) found that double osteotomy corrects all three angles best but overcorrects the DMAA most often, while a single distal osteotomy is the most consistent, with the fewest complications.

Hemiepiphysiodesis. Growth modulation carries little morbidity, but the radiographic correction is modest. Patient selection is critical, favouring young age, adequate remaining growth and a predominantly IMA deformity, and outcomes are variable.

Hypermobility and the Lapidus. Whether a hypermobile first ray mandates a first tarsometatarsal fusion in adolescents is unsettled. The procedure risks the physis and is generally deferred to maturity or to recurrence.

Minimally invasive techniques. Percutaneous, SERI and other MIS osteotomies report good short-term results, but long-term comparative evidence in skeletally immature patients is limited.

DMAA reliability. The angle has substantial inter-observer variability and is sensitive to rotation on radiographs, which complicates both classification and surgical planning.