Orthopaedic Surgery - Bunion/Hallux Valgus

Basics

A bunion is a prominent enlargement of the medial aspect of the first metatarsal head, often accompanied by overlying soft-tissue and bursal swelling.

Hallux valgus is a deformity centered mainly at the first metatarsophalangeal (MTP) joint. It consists of lateral deviation of the great toe together with medial deviation of the first metatarsal.

As the deformity progresses, subluxation or incongruity of the first MTP joint may develop.

General Prevention

Avoidance of narrow or constricting footwear may reduce symptoms and potentially limit progression in susceptible individuals.

Shoes with adequate width in the toe box are preferable.

Epidemiology

Hallux valgus occurs most commonly in middle-aged and older women, although adolescents and young adults may also be affected.

Females are affected more frequently than males.

The condition is seen predominantly in populations that routinely wear shoes and is much less common in traditionally unshod populations.

Prevalence

Hallux valgus affects approximately 23% of adults between 18 and 65 years of age.

Among adults older than 65 years, prevalence rises to approximately 35%.

Risk Factors

Important risk factors include heredity and footwear.

A positive family history is common, suggesting an inherited predisposition in many patients.

Narrow shoes and high heels may aggravate the deformity by increasing pressure across the forefoot and first MTP joint.

Genetics

A definite single genetic abnormality has not been identified.

However, approximately two-thirds of affected patients report a positive family history, indicating a substantial hereditary contribution.

Hallux valgus is also frequently associated with generalized ligamentous laxity syndromes, which themselves may have a genetic component.

Etiology

The development of hallux valgus is multifactorial.

Footwear with a narrow toe box or elevated heel is strongly associated with the condition.

Epidemiologic studies demonstrate a greater prevalence in shoe-wearing populations and increasing frequency when previously unshod societies adopt Western-style footwear.

Pes Planus

Pes planus may contribute to hallux valgus in some patients.

A pronated gait can alter mechanical loading through the first MTP joint and may increase stress on the medial column of the foot.

Flatfoot may also occur as part of a generalized ligamentous laxity pattern.

Metatarsus Primus Varus

Metatarsus primus varus, in which the first metatarsal deviates medially relative to the second, is strongly associated with hallux valgus.

As the angle between the first and second metatarsals increases, the risk and severity of hallux valgus also tend to increase.

Acquired Joint Laxity

Acquired ligamentous laxity can also contribute to deformity.

Conditions such as rheumatoid arthritis, gout, and previous trauma may weaken the soft-tissue restraints around the first MTP joint.

This allows progressive displacement of the first metatarsal and great toe.

Other Associated Factors

Other conditions that may contribute include amputation of another toe, severe lesser-toe deformities, and Achilles tendon contracture.

These conditions can alter forefoot biomechanics and increase abnormal pressure through the first ray.

Diagnosis

Signs and Symptoms

The most common symptom is pain over the medial eminence, usually caused by pressure from footwear.

The great toe deviates laterally, while the medial aspect of the first metatarsal becomes increasingly prominent.

The deformity may become more obvious during weight-bearing.

Shoe-Wear Problems

Many patients have difficulty finding comfortable footwear.

Pressure from the shoe over the medial bunion may produce irritation, redness, callus formation, or bursitis.

Cosmetic concern is also common, although appearance alone is not usually an indication for surgery.

Second-Toe Problems

In more advanced deformity, the great toe may impinge on or displace the second toe.

This can result in second-toe pain, hammering, crossover deformity, or other lesser-toe abnormalities.

Transfer Metatarsalgia

Hallux valgus may alter normal load distribution across the forefoot.

Patients can develop painful plantar callosities beneath the second metatarsal head, a condition often described as transfer metatarsalgia.

Pain may also arise directly from the first MTP joint, particularly when arthritis develops.

Physical Examination

The patient should be examined both sitting and standing because weight-bearing can accentuate the deformity.

The examiner should evaluate alignment of the great toe, first metatarsal, lesser toes, longitudinal arch, and hindfoot.

Achilles and Gastrocnemius Contracture

Ankle dorsiflexion should be assessed with the knee both flexed and extended.

Restricted dorsiflexion may indicate gastrocnemius or Achilles tendon contracture.

These contractures can contribute to abnormal forefoot loading.

Joint Motion

Motion should be assessed at the ankle, subtalar joint, midfoot, first tarsometatarsal joint, and MTP joints.

Restriction, crepitus, or pain at the first MTP joint may indicate associated arthrosis.

First-Ray Hypermobility

The first tarsometatarsal joint should be evaluated for excessive mobility or instability.

Vertical shear or manual stress can be used to assess the first ray.

Many patients with hallux valgus demonstrate some degree of first-ray hypermobility.

Flexibility of the Deformity

The examiner should determine whether the hallux valgus deformity can be manually corrected.

A flexible deformity is generally easier to treat than a rigid or fixed deformity.

The reducibility of the MTP joint is an important factor in surgical planning.

Foot Morphology

The overall shape of the foot and the status of the longitudinal arch should be documented.

Pes planus, metatarsus primus varus, lesser-toe deformities, and hindfoot malalignment may influence both symptoms and treatment.

Neurovascular Examination

A complete musculoskeletal and neurovascular examination of the lower extremity should be performed.

Peripheral vascular disease or neuropathy may substantially influence the safety and success of surgery.

Imaging

Weight-Bearing Radiographs

Standard evaluation includes standing anteroposterior, oblique, lateral, and axial sesamoid views of the foot.

Weight-bearing radiographs are essential because the deformity may appear less severe when the foot is unloaded.

Hallux Valgus Angle

The hallux valgus angle is measured between the longitudinal axes of the first metatarsal and proximal phalanx.

A normal value is generally less than 15°.

Increasing values indicate greater lateral deviation of the great toe.

Intermetatarsal Angle

The angle between the first and second metatarsals is used to assess metatarsus primus varus.

A normal first-second intermetatarsal angle is less than approximately 9°.

An increased angle is an important determinant of deformity severity and procedure selection.

Hallux Interphalangeal Angle

The hallux interphalangeal angle assesses alignment within the great toe itself.

A normal value is generally less than approximately 10°.

An increased angle may indicate hallux valgus interphalangeus and can influence the need for proximal phalanx osteotomy.

Distal Metatarsal Articular Angle

The distal metatarsal articular angle evaluates orientation of the first metatarsal head articular surface.

A normal value is approximately less than 10°.

An abnormal lateral slope can be associated with a congruent form of hallux valgus.

Sesamoid Position

Radiographs should assess displacement of the sesamoids relative to the first metatarsal head.

With progressive hallux valgus, the first metatarsal head shifts medially while the sesamoid complex remains relatively fixed.

This produces apparent lateral displacement of the sesamoids beneath the metatarsal head.

Joint Congruity and Arthritis

The first MTP joint should be assessed for congruity, subluxation, cartilage loss, osteophytes, and other degenerative changes.

These findings have a major influence on treatment selection.

Lesser-Toe Alignment

Radiographs should also evaluate the lesser toes for associated deformities.

Second-toe displacement, hammering, crossover deformity, or metatarsalgia may require simultaneous treatment.

Pathoanatomy

Hallux valgus is a three-dimensional deformity involving not only the first MTP joint but also the first tarsometatarsal joint and other components of the first ray.

The deformity can broadly be divided into congruent and incongruent types.

Incongruent Hallux Valgus

In an incongruent deformity, multiple static and dynamic abnormalities are present.

The first metatarsal drifts medially, increasing the intermetatarsal angle.

As the metatarsal head moves medially, the sesamoid complex remains relatively fixed by the transverse metatarsal ligament.

Dynamic Soft-Tissue Imbalance

As deformity progresses, the line of pull of the adductor hallucis, flexor hallucis brevis, extensor hallucis longus, and abductor hallucis becomes increasingly lateralized.

This further pulls the great toe into valgus and reinforces the deformity.

Capsular Changes

The medial capsule and ligaments become stretched and attenuated, while lateral soft tissues become progressively contracted.

These changes make the deformity increasingly difficult to correct manually as it advances.

Congruent Hallux Valgus

In congruent hallux valgus, the MTP joint remains anatomically congruent.

The articular surface may be abnormally sloped laterally, allowing the toe to remain aligned with the joint surface despite valgus orientation.

Because there is no pathologic joint subluxation, progression may be less pronounced than in an incongruent deformity.

Differential Diagnosis

The principal differential diagnosis is gout, which can produce pain, swelling, and prominence around the first MTP joint.

Acute gout usually presents with marked inflammation, redness, and tenderness rather than a gradually progressive structural deformity.

Treatment

General Measures

Hallux valgus should initially be treated with nonoperative measures.

Treatment is directed primarily toward reducing pain and improving shoe tolerance rather than correcting the structural deformity.

Footwear Modification

Proper footwear is one of the most important conservative measures.

Patients should avoid pointed shoes and high heels.

Lace-up shoes and styles with a wide toe box provide more space for the forefoot.

Shoe Adaptation

Soft leather shoes can sometimes be stretched over the medial bunion.

Shoes should ideally have no seam or stitching directly over the medial prominence.

Prescription footwear with additional width and depth may be required in severe cases.

Padding and Splints

Commercial pads, cushions, bunion sleeves, and splinting devices may reduce pressure over the medial eminence.

These devices can improve comfort but generally do not permanently correct the underlying deformity.

Orthotic Support

Patients with associated pes planus may benefit from custom or supportive orthoses.

Heel-cord stretching may be beneficial when Achilles or gastrocnemius tightness contributes to abnormal forefoot loading.

Physical Therapy

Physical therapy is usually of limited value for correcting the structural deformity or providing major long-term symptom relief.

Stretching may still be useful when there is an associated gastrocnemius or Achilles contracture.

Medication

Analgesic medications may be used for symptomatic relief.

NSAIDs or other simple analgesics can help when pain is associated with local inflammation or arthritis.

Goals of Surgery

The goals of operative treatment are pain relief, correction of deformity, restoration of more normal foot biomechanics, and preservation of useful joint motion whenever possible.

Procedure selection must be individualized.

Indications for Surgery

Surgery may be considered when there is persistent pain despite appropriate nonoperative treatment, progressive deformity, reduced function, or inability to tolerate reasonable footwear.

The severity of the deformity should be considered together with the patient’s symptoms.

Contraindications to Surgery

Surgery should generally not be performed for cosmetic concerns alone in an otherwise asymptomatic patient.

Significant vascular insufficiency is also a major contraindication because of the increased risk of poor wound healing and infection.

Surgical Decision-Making

Procedure selection depends on several factors, including patient age, severity of the intermetatarsal and hallux valgus angles, joint congruity, first-ray stability, arthritis, rigidity of the deformity, and associated lesser-toe pathology.

Numerous operative procedures have been developed because no single technique is appropriate for every patient.

Soft-Tissue Procedures

Soft-tissue procedures aim to rebalance the structures around the first MTP joint.

They may include release of contracted lateral tissues and tightening of the attenuated medial capsule.

These procedures are often combined with a metatarsal osteotomy.

Modified McBride Procedure

The modified McBride procedure may be used for selected mild deformities, usually as part of a combined correction.

It involves removal of the medial eminence, release of contracted lateral structures such as the adductor hallucis and lateral capsule, and tightening of the medial capsule.

Its purpose is to improve alignment and restore joint congruity.

Limitations of the Modified McBride Procedure

Soft-tissue correction alone may not adequately correct an increased intermetatarsal angle.

For this reason, the procedure is often combined with a metatarsal osteotomy.

Potential complications include overcorrection into hallux varus and joint stiffness.

Distal Chevron Osteotomy

A distal metatarsal chevron osteotomy involves a V-shaped cut near the metatarsal head.

The distal fragment is translated laterally to reduce the intermetatarsal angle and correct the deformity.

This procedure is most appropriate for mild to moderate hallux valgus.

Complications of Distal Chevron Osteotomy

Potential complications include malunion, osteonecrosis of the metatarsal head, stiffness, and hallux varus from overcorrection.

It generally provides insufficient correction for severe deformity.

Proximal Metatarsal Osteotomy

Proximal metatarsal osteotomy is generally reserved for moderate to severe deformity, particularly when the intermetatarsal angle is significantly increased.

The main purpose is to realign the first metatarsal relative to the second.

Types of Proximal Osteotomy

Several configurations have been described, including crescentic, oblique, opening-wedge, proximal chevron, Ludloff, and Scarf osteotomies.

These procedures may be combined with distal soft-tissue correction at the MTP joint.

Recurrence After Proximal Osteotomy

Recurrence after proximal metatarsal osteotomy has been reported in approximately 4–25% of cases.

Postoperative alignment and the quality of correction influence the risk of recurrent deformity.

Double Osteotomy

A double osteotomy combines proximal and distal correction.

It may be considered for severe hallux valgus when substantial angular correction is required.

One option combines a distal chevron with a proximal opening-wedge osteotomy.

Proximal Phalanx Osteotomy

Osteotomy of the proximal phalanx is used mainly for hallux valgus interphalangeus or as an additional procedure when metatarsal correction alone does not adequately align the great toe.

Akin Osteotomy

The Akin osteotomy is a medial closing-wedge osteotomy of the proximal phalanx.

It corrects valgus alignment within the great toe itself.

It is frequently performed in combination with another hallux valgus procedure.

Minimally Invasive Akin Osteotomy

Percutaneous and minimally invasive techniques have also been developed.

In selected patients, a minimally invasive Akin osteotomy can provide effective correction, sometimes without formal internal fixation.

Lapidus Procedure

The Lapidus procedure consists of fusion of the first tarsometatarsal joint combined with correction of the hallux valgus deformity.

It is particularly appropriate when there is hypermobility or instability of the first tarsometatarsal joint, significant metatarsus primus varus, or arthritis of the first TMT joint.

Effect of the Lapidus Procedure

By stabilizing and realigning the first ray, the Lapidus procedure can substantially reduce the intermetatarsal angle.

It is commonly used for moderate to severe deformities associated with first-ray instability.

First MTP Arthrodesis

Fusion of the first MTP joint may be appropriate for severe deformity, significant degenerative or inflammatory arthritis, connective tissue disorders, spasticity, or failed previous hallux valgus surgery.

It is also commonly considered in older patients with advanced joint destruction.

Results of MTP Fusion

MTP arthrodesis provides reliable pain relief and high patient satisfaction.

Its main disadvantage is permanent loss of motion at the first MTP joint.

However, many patients tolerate this well when the toe is fused in an appropriate functional position.

Prosthetic Arthroplasty

Joint replacement has been proposed as an alternative to fusion for arthritic first MTP joints.

However, prosthetic implants have historically demonstrated relatively high complication and failure rates.

They are generally used cautiously, particularly in younger or highly active individuals.

Keller Resection Arthroplasty

The Keller procedure involves removal of the medial eminence together with resection of part of the base of the proximal phalanx.

It is generally reserved for older, low-demand, sedentary patients.

Complications of Keller Arthroplasty

Potential problems include recurrent valgus deformity, transfer metatarsalgia, weakness of push-off, and cock-up deformity of the great toe.

Because of these limitations, it is rarely selected for younger or active patients.

Follow-Up

Patients treated nonoperatively should be reassessed if symptoms worsen, shoe tolerance decreases, or the deformity progresses.

Following surgery, clinical and radiographic follow-up is used to monitor wound healing, alignment, bone union, joint motion, and recurrence.

Prognosis

Mild and congruent deformities generally progress more slowly with conservative treatment than severe or incongruent deformities.

Nonoperative treatment can relieve symptoms but usually does not reverse the structural deformity.

Prognosis After Surgery

When surgery is performed for appropriate indications and the procedure is correctly matched to the deformity, most patients experience substantial pain relief and improvement in alignment.

Outcome depends on deformity severity, joint condition, procedure selection, and adherence to postoperative rehabilitation.

Complications

Potential surgical complications include wound breakdown, infection, recurrence of hallux valgus, overcorrection into hallux varus, malunion or nonunion, joint stiffness, neuroma formation, and transfer metatarsalgia.

Recurrence

Recurrent deformity may develop if the underlying metatarsal alignment, first-ray instability, or soft-tissue imbalance is not adequately corrected.

More severe initial deformities generally carry a higher risk of recurrence.

Hallux Varus

Excessive correction may produce hallux varus, in which the great toe deviates medially.

This can be painful and functionally limiting and may require additional treatment.

Transfer Metatarsalgia

Altered first-ray loading after surgery can shift excessive pressure to the lesser metatarsal heads.

This may produce persistent forefoot pain or plantar callosities, particularly beneath the second metatarsal.

Patient Monitoring

Patients should be monitored for progression of pain, changes in shoe tolerance, increasing deformity, development of lesser-toe problems, and signs of first MTP arthritis.

After surgery, follow-up should also assess wound healing, correction of alignment, bone union, joint motion, and recurrence of the deformity.