Views: 0 Author: Site Editor Publish Time: 2026-08-14 Origin: Site
Hallux valgus, commonly known as a bunion, is one of the most common forefoot deformities encountered in orthopedic and foot-and-ankle practice. It is characterized by a complex three-dimensional deformity involving the first ray, great toe, metatarsal head, sesamoid complex, and surrounding soft tissues.
Although hallux valgus may initially appear to be a simple lateral deviation of the great toe, its underlying pathology is considerably more complex. Progressive deformity can involve:
Lateral deviation of the great toe
Medial deviation of the first metatarsal
Rotation and pronation of the first metatarsal and hallux
Sesamoid displacement
First-ray instability
Transfer metatarsalgia
Lesser-toe deformities such as hammertoe
Understanding the three-dimensional biomechanics of hallux valgus is essential when selecting an appropriate treatment strategy.
For orthopedic surgeons, the key is not simply to "straighten the toe," but to restore the alignment and mechanical function of the first ray while maintaining a stable, painless and functional first metatarsophalangeal joint.
Hallux valgus is a progressive deformity of the first ray in which the great toe deviates laterally while the first metatarsal shifts medially.
The deformity typically consists of three major components:
The proximal phalanx gradually deviates toward the lesser toes, increasing the hallux valgus angle (HVA).
The first metatarsal moves medially, increasing the intermetatarsal angle (IMA).
Modern understanding increasingly recognizes that hallux valgus is not simply a two-dimensional deformity.
Pronation of the first metatarsal and great toe may contribute substantially to the three-dimensional deformity and alter the relationship between the metatarsal head and sesamoid complex.
This rotational component is important when planning corrective surgery.
The pathogenesis of hallux valgus is multifactorial.
A widely cited biomechanical concept proposed by Perera and colleagues emphasizes the importance of medial soft-tissue failure and joint capsule disruption during the early development of the deformity.
As the deformity progresses, changes occur in the bone, capsule, ligaments, sesamoids and intrinsic muscles.
Early weakening of the medial capsular and supporting structures reduces the stability of the first metatarsophalangeal joint.
This allows the hallux to progressively deviate laterally while the first metatarsal moves medially.
The resulting imbalance further accelerates deformity progression.
Progressive hallux valgus may produce:
Medial displacement of the first metatarsal head
Lateral deviation of the proximal phalanx
Lateral displacement of the sesamoid complex
Increased HVA
Increased IMA
Increased DMAA
First-ray instability
The sesamoid complex may gradually shift laterally relative to the first metatarsal head.
The extensor hallucis longus (EHL) and flexor hallucis longus (FHL) tendons can contribute to the deforming forces when the first metatarsophalangeal joint becomes malaligned.
The adductor hallucis also contributes to the lateral pull on the great toe.
As the metatarsal head moves medially away from the sesamoid complex, the intrinsic muscles may shift from their normal mechanical position.
The abductor hallucis may become displaced plantarly and laterally, contributing to:
Hallux pronation
First-ray instability
Plantarflexion-related deformity
Progressive loss of normal muscular balance
The windlass mechanism may also become less effective, contributing to altered forefoot loading.
Progressive hallux valgus may alter normal first-ray function and transfer excessive load to the lesser metatarsals.
A simplified biomechanical sequence is:
First-ray dysfunction → transfer metatarsalgia → increased loading of the second metatarsal → plantar plate stress or failure → lesser-toe instability → hammertoe deformity
This explains why some patients with advanced hallux valgus also present with:
Second metatarsalgia
Plantar plate pathology
Crossover toe
Hammertoe
Lesser-toe deformity
Therefore, surgical planning should evaluate the entire forefoot, rather than focusing exclusively on the great toe.
The sesamoid complex plays an important role in the biomechanics of the first metatarsophalangeal joint.
The plantar fat pad and surrounding fibrous structures stabilize the sesamoids beneath the proximal phalanx and first metatarsal head.
Important anatomical structures include:
Flexor hallucis brevis tendon
Medial and lateral sesamoids
Inter-sesamoid ligament
Adductor hallucis
Abductor hallucis
Flexor hallucis longus tendon
The flexor hallucis longus tendon passes between the sesamoids and interacts closely with the plantar soft-tissue complex.
Understanding this anatomy is particularly important during lateral release and sesamoid reduction.
Hallux valgus results from a combination of genetic, anatomical, biomechanical and environmental factors.
Important intrinsic risk factors include:
Female sex
Positive family history
Generalized ligamentous laxity
Pes planus
Abnormal first-ray mechanics
Neuromuscular disorders
Rheumatoid arthritis
Cerebral palsy
Genetic predisposition appears to play a significant role in many patients.
External factors may contribute to progression, particularly:
Narrow toe-box footwear
High-heeled shoes
Chronic forefoot compression
Improper footwear
However, footwear alone does not explain the development of hallux valgus. In many patients, footwear acts as a contributing factor rather than the primary cause.
Clinical assessment should evaluate both the deformity itself and the underlying biomechanics.
A comprehensive examination should include:
Great-toe alignment
First-ray mobility
First metatarsophalangeal joint range of motion
Sesamoid position
Lesser-toe alignment
Foot arch morphology
Achilles and gastrocnemius tightness
Hindfoot alignment
Plantar pressure distribution
Pain associated with hallux valgus can have different origins.
Pain may result from direct pressure between the bunion prominence and footwear.
Typical symptoms include:
Medial eminence pain
Shoe irritation
Local inflammation
Skin callus formation
Pain may also originate from:
Cartilage degeneration
Synovitis
First MTP joint arthritis
Joint incongruity
This distinction is important because correcting the visible deformity alone may not adequately address intra-articular pathology.
Radiographic evaluation is fundamental to surgical planning.
Weight-bearing AP and lateral radiographs of the foot should generally be obtained.
Non-weight-bearing radiographs may underestimate the severity of deformity and may provide misleading information regarding:
First-ray alignment
Relative metatarsal length
Joint congruency
First TMT stability
Overall forefoot mechanics
Four commonly assessed parameters are particularly useful.
The HVA measures the angular relationship between the first metatarsal and proximal phalanx.
A commonly used reference threshold is approximately:
HVA > 15°
The IMA evaluates the relationship between the first and second metatarsals.
A commonly used abnormal threshold is:
IMA > 9–10°
DMAA evaluates the orientation of the distal articular surface of the first metatarsal.
A commonly cited threshold is approximately:
DMAA > 10°
An increased DMAA may indicate an oblique or laterally oriented distal metatarsal articular surface.
The hallux interphalangeal angle evaluates the alignment between the proximal and distal phalanges.
An increased IPA may indicate the need for an additional phalangeal correction such as an Akin osteotomy.
Radiographic assessment should not stop at measuring angles.
The surgeon should also evaluate:
Lateral displacement of the sesamoids
First MTP joint congruency
Distal metatarsal articular orientation
First metatarsal pronation
First TMT joint alignment
Joint congruency describes whether the articular surfaces of the first metatarsal head and proximal phalanx remain appropriately aligned.
DMAA is an important parameter when evaluating this relationship.
In a congruent hallux valgus, the distal articular surface may remain relatively aligned with the proximal phalanx despite the overall deformity.
This has important surgical implications.
Hallux valgus can be broadly categorized according to HVA and IMA.
| Severity | HVA | IMA | Common Surgical Concept |
|---|---|---|---|
| Mild | <20° | <13° | Distal osteotomy |
| Moderate | 21–40° | 14–20° | Scarf/proximal correction depending on deformity |
| Severe | >40° | >20° | Double osteotomy ± Akin or proximal correction |
These thresholds are guidelines rather than absolute rules.
Modern surgical planning should consider the entire deformity rather than selecting an operation solely from HVA.
Conservative treatment is appropriate for many patients, particularly when symptoms are mild or surgery is not indicated.
Treatment options include:
Wide toe-box footwear
Shoe modification
Silicone toe spacers
Orthotic devices
Activity modification
Management of associated foot biomechanics
Conservative treatment generally aims to reduce symptoms rather than permanently correct the structural deformity.
Surgery is generally considered when the patient has:
Persistent pain
Difficulty wearing normal footwear
Progressive deformity
Transfer metatarsalgia
Associated lesser-toe deformity
First MTP arthritis
Failure of appropriate conservative treatment
Radiographic severity alone should not be the only indication for surgery.
Before selecting an operation, the surgeon should answer four fundamental questions.
Consider:
First TMT osteoarthritis
Significant first-ray instability
Severe metatarsus primus varus
Recurrent deformity
A Lapidus procedure may be appropriate in selected patients.
The required correction should be based on:
HVA
IMA
DMAA
First-ray pronation
Sesamoid position
Joint congruency
First TMT stability
An Akin osteotomy may be considered when residual hallux interphalangeal deformity remains after correction of the first metatarsal.
A Silfverskiöld test may help identify isolated gastrocnemius tightness.
In selected patients, gastrocnemius recession may be considered as part of the overall treatment strategy.
Several osteotomy techniques are available.
The Chevron osteotomy is commonly used for mild-to-moderate deformity.
Typical characteristics include:
Distal first metatarsal osteotomy
V-shaped configuration
Approximately 60° V angle in many techniques
Lateral translation of the metatarsal head
Its main purpose is to correct the distal component of the deformity while preserving first MTP joint motion.
The Scarf osteotomy is a versatile first-metatarsal osteotomy used for many moderate hallux valgus deformities.
Its major advantages include:
Three-dimensional correction
Medial/lateral translation
Rotational correction
Stable fixation
Adjustable correction magnitude
The goal is to reposition the first metatarsal head over the sesamoid complex and restore a more balanced first MTP joint.
The Akin osteotomy is a medial closing-wedge osteotomy of the proximal phalanx.
It is mainly used to correct residual hallux interphalangeal deformity.
Important technical considerations include:
Maintaining an appropriate correction angle
Avoiding excessive shortening
Protecting the flexor hallucis longus tendon
Avoiding excessive dorsiflexion or plantarflexion of the phalanx
Achieving stable fixation
Lateral soft-tissue release may be performed in conjunction with first-metatarsal osteotomy when clinically indicated.
A commonly described approach uses a dorsal incision at the first web space near the first MTP joint.
Structures that may be released include:
Metatarsosesamoid suspensory structures
Phalangeal attachment of the lateral sesamoid complex
Adductor hallucis tendon
Deep transverse metatarsal ligament
The precise sequence and extent of release vary according to the surgeon's technique and intraoperative findings.
The objective is to reduce lateral soft-tissue tension and facilitate restoration of the sesamoid and hallux alignment.
A typical Scarf osteotomy begins with a longitudinal medial incision along the first metatarsal.
Important technical considerations include:
Careful soft-tissue dissection is required to minimize injury to the medial dorsal cutaneous nerve and reduce postoperative sensory disturbance.
The capsule is opened and elevated carefully.
Preservation of plantar soft tissues is particularly important because the plantar vascular structures contribute to the blood supply of the first metatarsal head.
The Scarf cut is performed as a Z-shaped osteotomy.
A major technical concern is troughing, in which excessive compression or penetration of the cancellous bone results in loss of metatarsal height or rotational deformity.
The osteotomy should therefore be planned carefully to preserve structural stability.
Excessive shortening of the first metatarsal may increase the risk of:
Transfer metatarsalgia
Therefore, maintaining appropriate first-ray length is an important surgical objective.
Stable fixation may be achieved using appropriate screws, including compression or variable-pitch screw systems, according to the osteotomy design and surgeon preference.
Troughing refers to subsidence or collapse of the osteotomy construct into cancellous bone.
This may result in:
Loss of metatarsal height
Rotational malalignment
Reduced stability
Altered forefoot loading
Transfer metatarsalgia
Important principles include:
Preserve adequate cortical bone
Avoid excessive compression
Maintain appropriate osteotomy geometry
Ensure stable fixation
Avoid unnecessary disruption of vascular structures
The technical details of the osteotomy should always be adapted to the patient's anatomy.
The first tarsometatarsal joint is an important component of the medial longitudinal arch and first-ray stability.
First TMT instability may contribute to:
Metatarsus primus varus
Pes planus
Transfer metatarsalgia
Recurrent hallux valgus
A modified Lapidus procedure involves fusion of the first TMT joint and may be considered for selected patients with significant first-ray instability.
Potential indications include:
First TMT osteoarthritis
Significant first-ray hypermobility
Severe metatarsus primus varus
Recurrent hallux valgus in selected patients
Unlike historical procedures that incorporated additional intermetatarsal fusion, modern modified Lapidus techniques generally focus on stabilization of the first TMT joint.
The Keller procedure involves resection arthroplasty of the first MTP joint.
It may have a role in carefully selected low-demand patients, particularly in specific clinical situations.
However, potential disadvantages include:
Reduced push-off strength
Transfer loading
Cock-up deformity
Instability
Therefore, it is not generally considered the first choice for active patients requiring strong first-ray function.
A simple excision of the medial eminence does not correct the underlying biomechanical deformity.
If the first metatarsal remains medially deviated and the soft-tissue imbalance persists, recurrence is likely.
Therefore, modern hallux valgus surgery generally aims to correct:
Soft-tissue imbalance + first-metatarsal alignment + hallux alignment + sesamoid position
rather than simply removing the bunion prominence.
Although modern techniques can achieve reliable correction, complications remain possible.
Common early complications include:
Infection
Wound problems
Sensory disturbance
Medial dorsal cutaneous nerve injury
Swelling
Stiffness
Potential late complications include:
Recurrent hallux valgus
Hallux varus
Transfer metatarsalgia
Painful neuroma
First MTP stiffness
Avascular necrosis
Malunion
Nonunion following fusion
Hardware-related symptoms
Hallux varus represents excessive medial correction of the great toe.
It may occur after:
Excessive lateral soft-tissue release
Excessive medial correction
Over-tightening of the medial capsule
Excessive metatarsal correction
Treatment depends on whether the deformity is flexible or rigid.
Possible soft-tissue procedures may include:
Selective soft-tissue release
Medial capsular release
Tendon balancing
In severe or symptomatic cases, first MTP arthrodesis may provide a reliable salvage option.
The sesamoids are essential to normal first MTP biomechanics.
Therefore, unnecessary removal of the sesamoid complex should generally be avoided.
Preservation of the sesamoids helps maintain:
Push-off strength
Flexor hallucis brevis function
First MTP stability
Normal plantar loading
The objective of hallux valgus surgery is realignment, not removal of functional structures.
The blood supply to the first metatarsal head comes from multiple vascular sources, including branches associated with the first dorsal and plantar metatarsal arteries.
Excessive soft-tissue stripping may compromise blood supply.
Important preventive principles include:
Preserve plantar soft tissues
Avoid unnecessary vascular disruption
Minimize excessive periosteal stripping
Maintain appropriate osteotomy technique
Avascular necrosis remains an uncommon but potentially serious complication.
Juvenile hallux valgus differs in several important respects from adult hallux valgus.
It is frequently associated with:
Strong family history
Generalized ligamentous laxity
First-ray instability
Increased IMA
Increased DMAA
Flexible pes planus
Bilateral deformity
Pain may be less prominent than in adult patients.
Family history is particularly important.
Genetic factors may contribute to susceptibility through patterns of inheritance and variable penetrance.
Other associated factors include:
Ligamentous laxity
Pes planus
Neuromuscular disorders
Abnormal first-ray mechanics
Several characteristics may help distinguish juvenile from adult disease.
| Feature | Juvenile Hallux Valgus | Adult Hallux Valgus |
|---|---|---|
| Family history | Common | Variable |
| Bilateral involvement | Common | Variable |
| Pain | Often limited | Common |
| IMA | Frequently increased | Variable |
| DMAA | Frequently increased | Variable |
| First-ray laxity | Common | Variable |
| Pes planus | Common | Variable |
| Recurrence risk | Higher | Generally lower |
A comprehensive assessment should not focus exclusively on the foot.
The clinician should evaluate for potential neuromuscular or central causes of muscle imbalance.
Depending on the clinical presentation, assessment may include:
Neurological examination
Spine examination
Evaluation for cerebral palsy
Assessment for spinal dysraphism when clinically indicated
Beighton score for generalized hypermobility
Weight-bearing foot radiographs
Before skeletal maturity, conservative treatment is generally preferred when symptoms are limited.
Treatment may include:
Wide footwear
Orthotic support
Toe spacers
Activity modification
Monitoring progression
When significant deformity persists after skeletal maturity and symptoms justify surgery, treatment can generally follow adult hallux valgus principles.
Because juvenile patients may have greater ligamentous laxity and first-ray instability, procedures such as Lapidus-type correction may be considered in carefully selected cases.
Recurrence is one of the major concerns after surgical treatment of juvenile hallux valgus.
Reported recurrence rates vary considerably across studies and surgical techniques.
Potential contributing factors include:
Skeletal immaturity
Persistent ligamentous laxity
Inadequate correction
Uncorrected DMAA
First-ray instability
Pes planus
Genetic predisposition
Therefore, surgical planning should prioritize correction of the underlying biomechanical deformity, rather than simply correcting the visible hallux angle.
The modern approach to hallux valgus correction can be summarized as:
Restore appropriate:
HVA
IMA
DMAA
IPA
First-ray alignment
Reposition the first metatarsal head relative to the sesamoid complex.
Address first-metatarsal and hallux pronation when clinically significant.
Correct excessive medial and lateral soft-tissue forces.
The final objective is not simply radiographic correction.
The goal is a:
Stable + painless + functional first metatarsophalangeal joint.
A practical decision-making framework is:
Clinical symptoms
↓
Weight-bearing radiographs
↓
Measure HVA + IMA + DMAA + IPA
↓
Evaluate sesamoid position
↓
Assess first MTP congruency
↓
Evaluate first TMT stability
↓
Assess first MTP arthritis
↓
Determine required correction
↓
Select distal osteotomy / Scarf / proximal correction / double osteotomy / Lapidus
↓
Add Akin when indicated
↓
Perform appropriate soft-tissue balancing
↓
Stable fixation + postoperative rehabilitation
This algorithm emphasizes that no single radiographic angle should determine the entire operation.
The most important principles can be summarized in six points:
It involves translation, angulation and rotation.
Non-weight-bearing images may underestimate the deformity.
DMAA, IPA, sesamoid position and joint congruency should also be assessed.
Removing the medial eminence alone does not correct the underlying deformity.
Chevron, Scarf, proximal osteotomy, Akin and Lapidus procedures have different indications.
The objective is:
Restore alignment → restore biomechanics → balance soft tissues → preserve joint function.
Successful hallux valgus surgery depends not only on surgical planning but also on reliable orthopedic instrumentation.
Typical instrument requirements may include:
Hallux valgus osteotomy instruments
Scarf osteotomy instruments
Chevron osteotomy instruments
Akin osteotomy instruments
First MTP joint surgical instruments
Small bone retractors
Osteotomes
Bone saws
Drill guides
Screwdrivers
K-wires and guide pins
Compression instruments
Foot and ankle orthopedic instrument sets
For hospitals, orthopedic distributors and surgical centers, instrument selection should take into account osteotomy design, fixation system compatibility, surgical workflow and sterilization requirements.
Hallux valgus is multifactorial. Genetic predisposition, ligamentous laxity, first-ray biomechanics, foot morphology and footwear can all contribute. Narrow shoes and high heels may worsen symptoms but are not the sole cause.
An HVA of approximately 15° or less is commonly considered within the normal range, although radiographic thresholds should always be interpreted together with clinical findings.
Surgery is primarily considered for patients with persistent symptoms, difficulty with footwear, progressive deformity or associated forefoot pathology despite appropriate conservative treatment.
Neither procedure is universally superior. Chevron is commonly used for mild-to-moderate deformity, while Scarf provides greater versatility for correcting moderate deformity. Surgical selection should depend on the patient's HVA, IMA, DMAA, joint congruency, pronation and first-ray stability.
Akin osteotomy is a medial closing-wedge osteotomy of the proximal phalanx used primarily to correct hallux interphalangeal deformity.
Lapidus surgery may be considered when hallux valgus is associated with significant first TMT instability, first TMT arthritis, severe metatarsus primus varus or selected recurrent deformities.
Yes. Recurrence can occur, particularly when underlying factors such as first-ray instability, abnormal DMAA, pronation, ligamentous laxity or inadequate correction remain unaddressed.
Conservative treatment can reduce pain and improve footwear tolerance. However, non-surgical treatment generally cannot permanently reverse established structural deformity.
Hallux valgus is far more than a simple bunion.
It is a complex three-dimensional deformity involving the first metatarsal, proximal phalanx, sesamoid complex, first TMT joint and surrounding soft tissues.
Accurate treatment begins with a comprehensive clinical and radiographic assessment. Weight-bearing imaging should be used to evaluate HVA, IMA, DMAA, IPA, sesamoid position, joint congruency and first-ray stability.
Surgical correction should then be individualized.
Depending on the deformity, options may include:
Chevron osteotomy → Scarf osteotomy → proximal correction → double osteotomy → Akin osteotomy → Lapidus fusion
with appropriate soft-tissue balancing when necessary.
The ultimate goal is not simply to make the great toe appear straight on an X-ray.
It is to restore first-ray alignment, normalize biomechanics, rebalance the soft tissues, preserve first MTP function and provide a stable, painless and functional forefoot.
For orthopedic hospitals, surgeons and distributors, reliable surgical instrumentation is an equally important part of achieving a standardized and efficient workflow in foot-and-ankle surgery.
Toolmed provides orthopedic surgical instruments and customized instrument-set solutions for hallux valgus, osteotomy and foot-and-ankle procedures. Contact our team to discuss your surgical system and instrument requirements.
Perera AM, Mason L, Stephens MM. The pathogenesis of hallux valgus. The Journal of Bone and Joint Surgery. American Volume. 2011.
Coughlin MJ, Jones CP. Hallux valgus and first ray mobility. Journal of Bone and Joint Surgery.
Mann RA, Coughlin MJ. Hallux valgus—etiology, anatomy, treatment and surgical considerations.
Coetzee JC. Scarf osteotomy for hallux valgus correction and related technical considerations.
Lapidus PW. A quarter century of experience with the operative correction of the metatarsus varus primus in hallux valgus.
Johnson KA, et al. Surgical management of hallux valgus and associated forefoot deformities.
Contemporary foot and ankle orthopedic literature on hallux valgus classification, first-ray biomechanics, osteotomy techniques and postoperative outcomes.
