Exam Detail:

Key Revision Focus: Radiographic angles (HVA, IMA, DMAA). Joint Congruency vs Incongruency. Algorithm for Osteotomy Selection (Chevron vs Scarf vs Lapidus vs Akin). Complications (AVN, Hallux Varus, Recurrence). Arthrodesis for Salvage.

1. Clinical Overview

Hallux Valgus (HV) is a complex, progressive deformity of the first metatarsophalangeal (MTP) joint characterized by lateral (valgus) deviation of the great toe and medial deviation of the first metatarsal. The lay term "bunion" (from Latin "bunio," meaning turnip) refers to the prominent medial eminence of the first metatarsal head. It is one of the most common forefoot deformities, causing significant pain, cosmetic concern, and footwear difficulties.

Clinical Pearl:

The HV Triad: Always think of three components:

1. Lateral deviation of the Hallux (HVA).
2. Medial deviation of the 1st Metatarsal (IMA).
3. Pronation of the Hallux (sesamoids sublux laterally under the metatarsal head).

Key Concepts

1. Anatomy of the 1st MTP Joint:
   • Condyloid joint.
   • Stabilizers: Medial and Lateral Collateral Ligaments, Plantar Plate, Sesamoid Complex (Tibial/Medial & Fibular/Lateral sesamoids embedded in the FHB tendons), Adductor Hallucis, Abductor Hallucis.
   • In HV, the metatarsal "migrates" medially while the hallux deviates laterally. The sesamoids remain attached to the 2nd metatarsal via the deep transverse metatarsal ligament, so they appear to sublux laterally relative to the metatarsal head.
2. Etiology:
   • Intrinsic Factors:
     • Genetic predisposition (Strong family history in 60-90%).
     • Metatarsus Primus Varus (Congenital medial deviation of 1st MT).
     • Hypermobility of the 1st TMT (Tarsometatarsal) Joint.
     • Pes Planus (Flatfoot) - Increases pronation.
     • Ligamentous Laxity (e.g., Ehlers-Danlos).
     • Neuromuscular conditions (Cerebral Palsy, CVA).
   • Extrinsic Factors:
     • Footwear: Narrow toe box, high heels. Epidemiologically associated, but causation is debated. Likely accelerates progression in predisposed individuals.
3. Radiographic Assessment (CRITICAL FOR EXAM):
   • Weight-Bearing AP and Lateral X-rays are essential.
   • Hallux Valgus Angle (HVA):
     • Angle between the longitudinal axes of the 1st metatarsal and the proximal phalanx.
     • Normal: <15°. Mild: 15-20°. Moderate: 20-40°. Severe: >40°.
   • Intermetatarsal Angle (IMA):
     • Angle between the longitudinal axes of the 1st and 2nd metatarsals.
     • Normal: <9°. Mild: 9-11°. Moderate: 12-15°. Severe: >16°.
   • Distal Metatarsal Articular Angle (DMAA):
     • Angle between the articular surface of the 1st MT head and its longitudinal axis.
     • Normal: <10°. If abnormal, indicates lateral tilting of the articular surface.
   • Joint Congruency:
     • Congruent: The articular surfaces of the metatarsal head and proximal phalanx remain parallel and well-aligned despite the valgus position. The joint is "deformed as a unit." Often occurs in juveniles.
     • Incongruent (Subluxed): The proximal phalanx is subluxed laterally on the metatarsal head. There is mismatch between the joint surfaces. This is the more common adult pattern.
     • Clinical Importance: Congruent joints require osteotomies that realign the joint surface (e.g., DMAA correction), not just shift the metatarsal head. Incongruent joints can often be corrected with a simple distal osteotomy.
   • Sesamoid Position (Hardy & Clapham Classification):
     • Position of the Tibial (Medial) Sesamoid relative to the 1st MT axis.
     • Position 1: Sesamoid bisected by the axis. Position 7: Sesamoid completely lateral to the axis.
     • Higher positions indicate more severe pronation and deformity.
   • 1st TMT Joint Hypermobility:
     • Difficult to assess radiographically. Look for dorsiflexion of 1st MT on lateral view compared to the 2nd.
     • Coleman block test (removing the 1st MT from the ground) helps assess clinically.
   • Hallux Interphalangeus:
     • Valgus deformity occurs at the Hallux IP joint (between proximal and distal phalanges).
     • IP Angle >10° may confound the HVA measurement.
     • Requires an Akin osteotomy if significant.

Clinical Pearls

• "Bunion" is NOT the Bone: The "bunion" is the inflamed bursa and prominence over the medial eminence. It's a consequence of the bony deformity, not the cause.
• Pain vs. Cosmesis: Many patients tolerate the deformity without pain. Surgery is primarily for symptomatic HV. Cosmetic surgery alone is discouraged due to complication risk.
• Recurrence is Common: Even after "successful" surgery, recurrence rates are 10-20%. Patient counseling is crucial.
• Assess the Lesser Toes: HV often causes secondary 2nd toe problems (Hammer toe, Crossover toe, Transfer Metatarsalgia).

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2. Epidemiology

• Prevalence: Very common. Estimates range from 23-35% of the adult population. Increases with age.
• Sex: Female > Male. Ratio ranges from 2:1 to 9:1 across studies. Attributed in part to footwear differences.
• Age: Bimodal distribution. Juvenile HV (adolescence) and Adult HV (peak >65 years).
• Risk Factors:

  Risk Factor	Odds Ratio / Association
  Female Sex	OR ~3.0-5.0
  Family History	OR ~3.0-4.0 (First-degree relative)
  Age > 65 years	OR ~2.0
  Pes Planus (Flatfoot)	OR ~1.5-2.0
  Hypermobility	High Association
  Constrictive Footwear	Controversial (Accelerating factor?)
  Rheumatoid Arthritis	High (Inflammatory synovitis)

• Bilateral: >85% of cases are bilateral, though often asymmetric.

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3. Pathophysiology

The development and progression of Hallux Valgus is a complex interplay of mechanical, anatomical, and muscular factors leading to a self-perpetuating deformity.

Step 1: Initiating Event (Predisposition + Trigger)

• An individual with inherent predisposition (e.g., ligamentous laxity, metatarsus primus varus, pes planus, genetics) is exposed to extrinsic factors (e.g., footwear) or intrinsic triggers (e.g., growth spurt, weight gain).
• The first metatarsal begins to deviate medially at the first tarsometatarsal (TMT) joint (proximal instability) or at the metatarsal head.

Step 2: Muscle Imbalance and Deforming Forces

• As the 1st MT moves medially, the Adductor Hallucis muscle (attached to the lateral sesamoid and proximal phalanx base) becomes a deforming force. It pulls the hallux laterally.
• Simultaneously, the Abductor Hallucis (medial stabilizer) loses its mechanical advantage. It migrates plantarwards and becomes more of a flexor than an abductor.
• The Extensor Hallucis Longus (EHL) and Flexor Hallucis Longus (FHL) become "bowstrings" – their tendons are no longer centered over the MTP joint. They pull laterally, accelerating the valgus drift.
• The hallux also begins to pronate (rotate externally with the nail facing medially).

Step 3: Sesamoid Subluxation and Joint Incongruity

• The sesamoids are anchored to the 2nd metatarsal via the deep transverse metatarsal ligament. As the 1st MT moves medially, the sesamoids appear to sublux laterally relative to the MT head.
• The crista (ridge on the plantar metatarsal head between the sesamoid grooves) may erode.
• The medial collateral ligament stretches and attenuates.
• The lateral capsule and adductor hallucis tendon contract.
• The joint becomes incongruent (in most adult cases). The proximal phalanx articulates with a progressively lateral portion of the metatarsal head.

Step 4: Medial Eminence Prominence and Bursa Formation

• As the MT head deviates medially, it becomes prominent under the skin.
• Pressure from footwear causes friction over this prominence.
• A protective adventitious bursa forms over the medial eminence. This bursa can become inflamed (bursitis), causing the classic "bunion" pain and swelling.
• With chronic irritation, the bursa may become thickened and fibrous.

Step 5: Progressive Deformity and Secondary Changes

• Without intervention, the deformity progresses. HVA and IMA increase.
• Osteoarthritis may develop in the 1st MTP joint due to abnormal loading and joint incongruity.
• Lesser Toe Deformities: The hallux may impinge on the 2nd toe, causing it to dorsiflex (Hammer Toe), crossover, or subluxe.
• Transfer Metatarsalgia: The dysfunctional 1st ray no longer bears its share of weight. Load transfers to the 2nd and 3rd metatarsal heads, causing pain and callus formation.

Step 6: End-Stage Deformity

• Severe HV with fixed contractures.
• Complete sesamoid dislocation lateral to the metatarsal head.
• Arthritic changes in the MTP joint.
• Fixed lesser toe deformities.
• Treatment may require arthrodesis (fusion) rather than corrective osteotomy.

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4. Clinical Presentation

Symptoms

1. Pain:
   • Location: Over the medial eminence ("bunion"). May radiate along the 1st MT.
   • Character: Aching, burning, sharp with shoe pressure.
   • Aggravating Factors: Wearing narrow or tight shoes. Prolonged walking.
   • Relieving Factors: Barefoot, wide shoes, rest.
2. Cosmetic Concerns:
   • Protrusion of the medial eminence.
   • Deviation of the great toe towards the lesser toes.
   • Difficulty finding attractive footwear.
3. Footwear Difficulties:
   • Unable to fit narrow shoes.
   • Pain with heels.
4. Secondary Symptoms:
   • 2nd Toe Pain: Hammer toe, crossover toe, MTP synovitis.
   • Metatarsalgia: Pain under the 2nd/3rd MT heads.
   • Calluses: Plantar to 2nd/3rd MT heads. Dorsal on 2nd toe PIP (hammer toe).

Red Flags

Red Flag	Consider
Rapid Progression	Inflammatory Arthritis (RA, Gout, Psoriatic)
Acute Pain, Swelling, Erythema	Gout, Septic Arthritis, Infection
Stiffness	Hallux Rigidus (OA of 1st MTP), RA
Neurovascular Changes	PVD, Diabetic Foot
History of Trauma	Fracture, Ligament Rupture

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5. Clinical Examination

1. Look (Inspection)

• Weight-Bearing Stance (Front, Side, Behind):
  • Degree of Hallux Valgus deviation.
  • Medial eminence prominence.
  • Pronation of the Hallux (nail rotation).
  • Metatarsus Primus Varus (medial angulation of 1st ray).
  • Pes Planus / Pes Cavus.
  • Lesser toe deformities (Hammer toe, Claw toe, Crossover 2nd toe).
• Skin:
  • Redness/Inflammation over medial eminence (bursitis).
  • Calluses (Plantar 2nd/3rd MT, Medial eminence, Dorsal PIP of 2nd toe).
  • Ulceration (Diabetic/Neuropathic).
• Footwear: Examine the patient's shoes. Look for wear pattern, toe box width.

2. Feel (Palpation)

• Medial Eminence: Tender? Fluctuant bursa?
• 1st MTP Joint: Point tenderness suggests arthritis.
• Sesamoids: Tender sesamoids suggest sesamoiditis.
• 2nd MTP Joint: Dorsal and plantar palpation. Drawer test for plantar plate rupture.
• 1st TMT Joint: Tenderness suggests instability or arthritis at the base.
• Pulses: Posterior Tibial, Dorsalis Pedis. Capillary refill.
• Sensation: Check for diabetic neuropathy.

3. Move (Range of Motion)

• 1st MTP Joint:
  • Normal ROM: Dorsiflexion 70-90°. Plantarflexion 25-45°.
  • Hallux Rigidus: Reduced dorsiflexion with pain ("grind test" positive – pain with axial loading and rotation).
  • Hallux Limitus: Early reduction in DF.
• Correct the Deformity:
  • Passively correct the hallux valgus. Is it fully correctable? Does this cause the 1st MT to "push up" (indicating 1st TMT instability)?
• 1st TMT Joint (Hypermobility Assessment):
  • Stabilize the 2nd MT with one hand. Grasp the 1st MT head with the other.
  • Dorsiflexion-Plantarflexion translation: >4-5mm of total excursion or asymmetric motion compared to 2nd MT suggests hypermobility.
  • This is somewhat subjective.
• Windlass Mechanism:
  • Dorsiflex the great toe. This should tighten the plantar fascia and raise the medial arch.
  • Failure suggests plantar aponeurosis dysfunction or severe pes planus.

4. Special Tests

• Grind Test (1st MTP): Axially load and rotate the hallux. Pain suggests arthritis.
• Drawer Test (2nd MTP): Assess plantar plate integrity for 2nd MTP instability.
• Silfverskiöld Test: Assess Gastrocnemius tightness. Equinus can contribute to forefoot overload. Knee extended vs flexed ankle DF.

5. Neurovascular and Gait Assessment

• Pulses: Critical before surgery.
• Sensation: 10g monofilament. Two-point discrimination.
• Gait: Observe for antalgic gait, loss of push-off from 1st ray, compensatory patterns.

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6. Investigations

First-Line: Plain Radiographs (X-ray)

• Views: Weight-Bearing AP and Lateral of the foot. Essential.
• Measurements (MUST KNOW FOR EXAM):

  Measurement	How to Measure	Normal	Significance
  Hallux Valgus Angle (HVA)	Angle between 1st MT axis & Proximal Phalanx axis	<15°	Severity of Hallux deviation
  Intermetatarsal Angle (IMA)	Angle between 1st MT axis & 2nd MT axis	<9°	Severity of Metatarsus Primus Varus
  Distal Metatarsal Articular Angle (DMAA)	Angle between 1st MT articular surface & 1st MT axis	<10°	Lateral tilt of joint surface (Congruent HV)
  Interphalangeal Angle (IPA)	Angle between Proximal & Distal Phalanx of Hallux	<10°	Hallux Interphalangeus
  Sesamoid Position	Position of Tibial sesamoid relative to 1st MT axis	1-3	Degree of pronation/sesamoid subluxation

• Joint Congruency: Look at the articular surfaces on AP view. Are they parallel (congruent) or mismatched (incongruent/subluxed)?
• 1st MTP Arthritis: Joint space narrowing, osteophytes, subchondral sclerosis.
• 1st TMT Arthritis/Instability: Joint space narrowing at the base. Dorsiflexion of 1st MT on lateral (compare to 2nd/3rd).

Second-Line: Advanced Imaging

• MRI:
  • Rarely needed for simple HV.
  • Useful if: Sesamoid pathology suspected, AVN post-surgery, infection, atypical mass.
• CT Scan:
  • Rarely needed.
  • May be used for complex revision cases or if considering fusion.
• Weight-Bearing CT (WBCT):
  • Emerging modality. Allows 3D assessment under physiological load.
  • May improve assessment of 1st TMT instability, sesamoid position.

Blood Tests (If Indicated)

• Uric Acid, ESR, CRP, RF, Anti-CCP: If inflammatory arthritis (Gout, RA) is suspected.

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7. Management

The goal of HV treatment is to relieve pain and improve function. Surgery should only be considered for symptomatic patients who have failed conservative measures.

                        HALLUX VALGUS
                              ↓
┌─────────────────────────────────────────────────────────────┐
│                    INITIAL ASSESSMENT                       │
│  - Symptom severity (Pain, Cosmesis, Function)              │
│  - Physical Examination (ROM, Stability, Lesser Toes)       │
│  - Weight-Bearing X-rays (HVA, IMA, DMAA, Congruency)       │
└─────────────────────────────────────────────────────────────┘
                              ↓
┌─────────────────────────────────────────────────────────────┐
│              CONSERVATIVE MANAGEMENT (FIRST LINE)           │
├─────────────────────────────────────────────────────────────┤
│  1. Footwear Modification (Wide Toe Box, Low Heel)          │
│  2. Padding (Bunion Pads, Gel Sleeves)                      │
│  3. Orthotics (Arch support, NOT night splints for adults)  │
│  4. NSAIDs for Bursitis                                     │
│  5. Physiotherapy (Stretching, Intrinsic Strengthening)     │
└─────────────────────────────────────────────────────────────┘
                              ↓
                   ┌─────────┴─────────┐
                   │ SYMPTOMS PERSIST? │
                   └─────────┬─────────┘
                   ↓ NO                YES ↓
┌────────────────────────┐         ┌─────────────────────────────────┐
│  CONTINUE CONSERVATIVE │         │ SURGICAL INTERVENTION           │
│  - Patient Education   │         │ (Based on Deformity Severity)   │
│  - Monitoring          │         └─────────────────────────────────┘
└────────────────────────┘                       ↓
                          ┌──────────────────────────────────────────────────┐
                          │         SURGICAL ALGORITHM (SEE BELOW)           │
                          │  - Mild (HVA<30, IMA<13): Distal Osteotomy       │
                          │  - Moderate (HVA 30-40, IMA 13-16): Scarf, Prox  │
                          │  - Severe (HVA>40, IMA>16): Lapidus, Fusion      │
                          │  - +/- Akin if IPA elevated                      │
                          │  - +/- Lateral Release                           │
                          └──────────────────────────────────────────────────┘

Surgical Algorithm (Osteotomy Selection - THE KEY EXAM TOPIC)

Deformity Severity	HVA	IMA	Recommended Procedure(s)
Mild	<30°	<13°	Distal Metatarsal Osteotomy (Chevron, Mitchell)
Moderate	30-40°	13-16°	Scarf Osteotomy, Proximal Chevron, Combined Proximal + Distal
Severe	>40°	>16°	Lapidus Procedure (1st TMT Fusion), Double/Triple Osteotomy
Arthritic 1st MTP	Any	Any	First MTP Arthrodesis (Fusion)
Congruent Joint	Any	Any	DMAA-correcting osteotomy (Medial closing wedge, Biplanar Chevron)
1st TMT Hypermobility	Any	Any	Lapidus Procedure (1st TMT Fusion)
Hallux Interphalangeus	IPA >10°		Add Akin Osteotomy (Proximal Phalanx)

1. Conservative Management

• Footwear Modification:
  • Wide toe box. Soft leather or mesh uppers. Low heel (<2.5 cm).
  • Open-toed sandals. Custom extra-depth shoes.
• Padding and Orthotics:
  • Bunion pads (gel, felt) protect the medial eminence.
  • Toe spacers between 1st and 2nd toes.
  • Arch supports may help in pes planus.
  • Night Splints: NO EVIDENCE they correct adult HV. May provide symptom relief in some.
• Medications: NSAIDs for acute bursitis.
• Physiotherapy: Gentle stretching of the hallux. Intrinsic muscle strengthening. Calf stretching if equinus present.
• Outcome: Conservative management does NOT correct the deformity. It manages symptoms.

2. Surgical Management: Key Procedures

A. Distal Metatarsal Osteotomies (Mild HV)

• Chevron Osteotomy:
  • Technique: V-shaped (60-70° angle) osteotomy through the 1st MT head. The capital fragment (head) is translated laterally by ~5-7mm.
  • Fixation: K-wire or headless compression screw.
  • Correction Capability: HVA correction ~10-15°. IMA correction ~5°.
  • Indications: Mild-Moderate HV (HVA <35°, IMA <15°). Incongruent joint.
  • Contraindications: Severe HV, Arthritis, Poor bone quality.
  • Pros: Stable, Simple, Predictable.
  • Cons: Limited correction, Risk of AVN if excessive soft tissue stripping.
• Mitchell Osteotomy:
  • Step-cut osteotomy. Allows lateral and some shortening.
  • Less commonly used now due to metatarsal shortening and transfer metatarsalgia.

B. Shaft Osteotomies (Moderate HV)

• Scarf Osteotomy:
  • Technique: Z-shaped osteotomy through the 1st MT shaft. Named after joinery term. Allows multiplanar correction (translation, rotation, shortening, angulation).
  • Fixation: Two headless compression screws.
  • Correction Capability: HVA correction up to 25-30°. IMA correction ~8-10°. Can also correct DMAA (troughing/rotation).
  • Indications: Moderate HV (HVA 30-40°, IMA 13-16°).
  • Pros: Versatile, Good stability, Large surface area for healing, Can correct DMAA.
  • Cons: Technically demanding, Risk of "Troughing" (plantar displacement).
  • TROUGHING: The capital fragment sinks plantarward through the osteotomy site. Causes plantar prominence and pain. Fix with good technique and fixation.

C. Proximal Metatarsal Osteotomies (Moderate-Severe HV)

• Proximal Chevron / Opening Wedge:
  • Osteotomy at the base of the 1st MT. Opening wedge medially to correct IMA.
  • May need bone graft.
  • Good IMA correction.
  • Disadvantage: Can shorten the 1st MT (closing wedge).
• Basal Crescentic Osteotomy:
  • Curved osteotomy at the MT base. Allows rotation.
  • Technically difficult, risk of dorsiflexion malunion.

D. Lapidus Procedure (1st TMT Arthrodesis) (Severe HV / Hypermobile 1st Ray)

• Technique: Fusion of the 1st Tarsometatarsal (TMT) joint.
• Indication:
  • Severe HV (HVA >40°, IMA >16°).
  • 1st TMT Joint Hypermobility.
  • 1st TMT Arthritis.
• Rationale: Addresses the deformity at its apex – the hypermobile/unstable TMT joint. Provides permanent correction.
• Fixation: Two crossed screws, Locking plate, or Dorsal plate with screws.
• Pros: Addresses proximal instability, High correction potential.
• Cons: Longer healing time (bone healing for fusion), Risk of Non-union (~5-10%), Stiffness at the 1st ray.

E. Akin Osteotomy (Proximal Phalanx Osteotomy)

• Technique: Medial closing wedge osteotomy of the proximal phalanx base.
• Indication: Hallux Interphalangeus (IPA >10°). To "fine-tune" the hallux alignment after a metatarsal osteotomy.
• Fixation: Staple or K-wire.
• Often combined with Chevron or Scarf: "Scarf-Akin," "Chevron-Akin."

F. First MTP Arthrodesis (Fusion)

• Indication:
  • End-stage HV with 1st MTP arthritis.
  • Severe HV in elderly with poor bone quality.
  • Rheumatoid Arthritis.
  • Failed previous HV surgery (Salvage).
  • Neuromuscular HV (e.g., Cerebral Palsy).
• Technique: Excise the articular surfaces. Position the hallux in ~15° valgus, ~15° dorsiflexion (relative to floor with foot flat), neutral rotation. Fuse with plate and screws.
• Outcome: Excellent pain relief. Eliminates MTP motion but gait is surprisingly well tolerated due to IP joint compensation.

G. Lateral Soft Tissue Release (LSTR)

• Purpose: To release the contracted lateral structures (Adductor Hallucis, Lateral Capsule, Deep Transverse Metatarsal Ligament sling over fibular sesamoid) that are pulling the hallux laterally.
• Almost always performed in conjunction with a metatarsal osteotomy. It is rarely sufficient alone.
• Technique: Can be done through a 1st web space incision (separate from medial incision) or through the medial capsule.

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8. Complications

General Complications

Complication	Incidence	Notes
Recurrence of HV	10-20%	Progressive disease. May need revision.
Hallux Varus (Overcorrection)	2-10%	Hallux points medially. Difficult to manage. May need revision/fusion.
Avascular Necrosis (AVN) of MT Head	1-5%	Risk higher with distal osteotomies (Chevron) if lateral capsule also released. Presents with pain, collapse on X-ray.
Metatarsalgia / Transfer Pain	5-15%	Pain under 2nd/3rd MT heads if 1st ray is shortened or elevated.
Shortening of 1st Metatarsal	Variable	Some osteotomies shorten the ray. Excessive shortening causes transfer metatarsalgia.
Malunion / Non-union	1-5%	Malunion: Dorsiflexion (elevated 1st MT) or plantarflexion. Non-union: Rare with good fixation.
Stiffness	5-20%	Reduced ROM at 1st MTP. May require manipulation under anaesthesia (MUA) or arthrolysis.
Infection	1-3%	Superficial or deep. Higher risk in diabetics.
Nerve Injury	1-5%	Dorsomedial Cutaneous Nerve of the Hallux. Causes numbness or neuroma.
DVT / PE	<1%	Thromboprophylaxis advised.
Hardware Irritation	5-15%	Painful prominent screws/staples. May need removal.

Specific Complications by Procedure

• Chevron: AVN (2-5% if combined with LSTR through same incision).
• Scarf: Troughing. Stress fracture at the osteotomy apices.
• Lapidus: Non-union of TMT fusion (~5-10%). Shortened 1st ray.
• Akin: Fracture through osteotomy site if weight-bearing too early.
• Fusion (MTP): Non-union. Malpositioning (excessive DF, VR, or DR).

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9. Prognosis & Outcomes

• Conservative Management: Does not alter natural history. Provides symptomatic relief in many.
• Surgical Management:
  • Overall patient satisfaction rates are high (~80-90%).
  • Pain relief is achieved in the majority.
  • Recurrence rates vary by procedure and severity.
  • Modern techniques (Scarf, Lapidus) have lower recurrence rates than older procedures but higher technical demands.
• Return to Activity:
  • Distal osteotomies (Chevron): Heel walking in stiff-soled shoe immediately. Transition to regular shoes at 4-6 weeks.
  • Scarf: Similar, though slightly longer protection.
  • Lapidus: Non-weight bearing or protected weight bearing for 6-8 weeks until fusion confirmed.
  • Full return to high-impact activity/sports: 3-6 months.

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10. Evidence & Guidelines

Guidelines

• No single universally adopted guideline for HV surgery exists.
• AAOS / AOFAS / COFAS Consensus:
  • Surgery for symptomatic patients only.
  • Procedure selection based on deformity severity (HVA, IMA, Congruency, TMT stability).
  • Distal osteotomy for mild, Shaft/Proximal for moderate, Lapidus for severe/hypermobile.
  • Fusion for arthritis or salvage.

Landmark Papers & Evidence

1. Austin DW, Leventen EO. A new osteotomy for hallux valgus: a horizontally directed "V" displacement osteotomy of the metatarsal head for hallux valgus and primus varus. Clin Orthop Relat Res. 1981 Jun;(157):25-30. [PMID: 7249456]
   • The original description of the Chevron osteotomy.
2. Weil LS Sr. Scarf osteotomy for correction of hallux valgus. Historical perspective, surgical technique, and results. Foot Ankle Clin. 2000 Sep;5(3):559-80. [PMID: 11232397]
   • Key paper on the Scarf osteotomy technique and versatility.
3. Lapidus PW. A quarter of a century of experience with the operative correction of the metatarsus varus primus in hallux valgus. Bull Hosp Joint Dis. 1956 Oct;17(2):404-21. [PMID: 13383016]
   • Original description of the Lapidus procedure for 1st TMT arthrodesis.
4. Coughlin MJ, Jones CP. Hallux valgus: demographics, etiology, and radiographic assessment. Foot Ankle Int. 2007 Jul;28(7):759-77. [PMID: 17666168]
   • Comprehensive review of HV epidemiology and radiographic evaluation.
5. Easley ME, Trnka HJ. Current concepts review: hallux valgus part 1: pathomechanics, clinical assessment, and nonoperative management. Foot Ankle Int. 2007 Jul;28(7):748-58. [PMID: 17666167]
   • Excellent review on pathophysiology and conservative management.
6. Easley ME, Trnka HJ. Current concepts review: hallux valgus part II: operative treatment. Foot Ankle Int. 2007 Jul;28(7):748-58. [PMID: 17666167] (Part II)
   • Companion review on surgical options.
7. COFAS (Canadian Orthopaedic Foot and Ankle Society) Study Group. Consensus on Hallux Valgus. (Various publications).
   • Work towards standardizing classification and treatment algorithms.
8. Trnka HJ, et al. Comparison of the results of the Scarf and Chevron osteotomies for the correction of hallux valgus. Foot Ankle Int. 2013 Nov;34(11):1518-25. [PMID: 23776005]
   • Prospective comparison. Both effective. Scarf may offer more correction.

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11. Patient Explanation

What is a Bunion?

A bunion is a bony bump on the side of your big toe joint. It happens because your big toe starts to lean towards your other toes, and the bone at the base of your big toe sticks out medially. It's not just a growth of bone; it's a realignment of the joint.

Why do I have it?

It's mainly due to the way your foot is built – the shape of your bones and how loose your ligaments are. This tends to run in families. Tight, pointed shoes can make it worse, but they probably don't cause it in the first place.

Does it get worse?

Often, yes, slowly over time. The angle of the toe can increase.

What can we do without surgery?

• Wear wider shoes. This is the most important thing. Shoes with a roomy toe box and low heels.
• Use pads or spacers to cushion the bump.
• Anti-inflammatory tablets can help if the bump is sore and swollen.
• These things will not straighten your toe, but they can make it more comfortable.

When do I need surgery?

Surgery is only for painful bunions that don't get better with shoe changes and padding. We don't operate just to make the foot look nicer, because there are real risks involved.

What does surgery involve?

It depends on how severe your bunion is. Usually, we shave off the bony bump and cut the metatarsal bone (the long bone behind the toe) to realign it. We use screws to hold it in place. Sometimes we need to do more than one cut, or fuse a joint if it's very bad or arthritic.

What are the risks?

• The bunion can come back (about 1 in 10 people).
• The toe can overcorrect and point the other way (Hallux Varus).
• Stiffness of the big toe.
• Numbness at the side of the toe.
• Infection (rare).
• The blood supply to the bone can be damaged (AVN - rare).

What is recovery like?

You'll usually be walking the same day, but in a special stiff-soled boot or sandal for 4-6 weeks. Swelling can take 3-6 months to fully settle. You can usually return to driving and normal shoes after about 6-8 weeks. Full recovery for high-impact sports takes 3-6 months.

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12. References

1. Austin DW, Leventen EO. A new osteotomy for hallux valgus: A horizontally directed "V" displacement osteotomy of the metatarsal head. Clin Orthop Relat Res. 1981;(157):25-30. [PMID: 7249456]
2. Weil LS Sr. Scarf osteotomy for correction of hallux valgus. Foot Ankle Clin. 2000;5(3):559-80. [PMID: 11232397]
3. Lapidus PW. A quarter of a century of experience with operative correction of metatarsus varus primus in hallux valgus. Bull Hosp Joint Dis. 1956;17(2):404-21. [PMID: 13383016]
4. Coughlin MJ, Jones CP. Hallux valgus: demographics, etiology, and radiographic assessment. Foot Ankle Int. 2007;28(7):759-77. [PMID: 17666168]
5. Easley ME, Trnka HJ. Current concepts review: hallux valgus part 1: pathomechanics, clinical assessment. Foot Ankle Int. 2007;28(7):748-58. [PMID: 17666167]
6. Easley ME, Trnka HJ. Current concepts review: hallux valgus part II: operative treatment. Foot Ankle Int. 2007;28(7):759-77. (Part II).
7. Mann RA, Coughlin MJ. Hallux valgus – etiology, anatomy, treatment and surgical considerations. Clin Orthop Relat Res. 1981;(157):31-41. [PMID: 7249461]
8. Trnka HJ, et al. Comparison of Scarf and Chevron osteotomies. Foot Ankle Int. 2013;34(11):1518-25. [PMID: 23776005]
9. Okuda R, Kinoshita M, Yasuda T, et al. The shape of the intermetatarsal angle. J Bone Joint Surg Am. 2007;89(11):2490-5.
10. Nery C, Coughlin MJ, Baumfeld D, Ballerini FJ, Kobata S. Hallux valgus in males – part 1: demographics, etiology, and comparative radiology. Foot Ankle Int. 2013;34(5):629-35. [PMID: 23386751]
11. Robinson AH, Limbers JP. Modern concepts in the treatment of hallux valgus. J Bone Joint Surg Br. 2005;87(8):1038-45. [PMID: 16049235]
12. Shibuya N, Thorud JC, Martin LR, Isaacs JL, Jupiter DC. Evaluation of hallux valgus correction with versus without Akin proximal phalanx osteotomy. J Foot Ankle Surg. 2016;55(5):910-4. [PMID: 27353999]
13. Pinney SJ, Song KR, Chou LB. Surgical treatment of mild hallux valgus deformity: the state of practice among academic foot and ankle surgeons. Foot Ankle Int. 2006;27(11):970-3. [PMID: 17144970]
14. Barouk LS. Scarf osteotomy for hallux valgus correction. Local anatomy, surgical technique, and combination with first phalanx osteotomy. Foot Ankle Clin. 2000;5(3):525-58. [PMID: 11232396]
15. Devries JG, Granata JD, Hyer CF. Fixation of first tarsometatarsal arthrodesis: a retrospective comparative cohort of two techniques. Foot Ankle Int. 2011;32(2):158-62. [PMID: 21288417]

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13. Examination Focus

Common Exam Questions (FRCS/Boards)

1. What are the key radiographic measurements in Hallux Valgus? (Answer: HVA, IMA, DMAA, Sesamoid Position, Congruency).
2. How do you choose between a Chevron, Scarf, and Lapidus procedure? (Answer: Chevron for Mild (HVA<30, IMA<13). Scarf for Moderate (HVA 30-40, IMA 13-16). Lapidus for Severe (HVA>40, IMA>16) or 1st TMT Hypermobility).
3. What is a Congruent vs Incongruent HV joint? (Answer: Congruent = articular surfaces are parallel, deformed as a unit. Requires DMAA correction. Incongruent = subluxed, phalanx translated on MT head. More common adult pattern).
4. What is "Troughing" and how do you prevent it? (Answer: Plantar descent of the capital fragment with Scarf osteotomy. Prevent with good bone cuts, adequate fixation, careful fragment manipulation).
5. What is Hallux Varus? (Answer: Overcorrection. Hallux points medially. Caused by over-resection of medial eminence, excessive LSTR, or overcorrection of osteotomy. Difficult to manage – may need revision/fusion).
6. What are the risks of AVN with Chevron? (Answer: ~2-5%. Risk increases if combined with aggressive lateral soft tissue release through the same exposure. Preserve lateral capsule pedicle or use separate 1st webspace incision).
7. What is the Akin osteotomy? (Answer: Medial closing wedge of the proximal phalanx. Used for Hallux Interphalangeus or to fine-tune alignment).
8. What is the indication for 1st MTP Fusion? (Answer: Arthritic 1st MTP, Severe HV with poor bone, RA, Neuromuscular HV, Failed previous surgery).

Viva "Buzzwords"

• "HVA, IMA, DMAA"
• "Congruent vs Incongruent"
• "Sesamoid Subluxation"
• "Chevron for Mild, Scarf for Moderate, Lapidus for Severe"
• "Troughing"
• "Hallux Varus"
• "AVN Risk"
• "Akin Osteotomy"
• "First TMT Hypermobility"

Common Pitfalls

• Operating for Cosmesis Alone: High risk of dissatisfaction.
• Wrong Procedure Selection: Chevron for severe HV will recur.
• Ignoring 1st TMT Instability: Must do Lapidus if hypermobile, or recurrence is inevitable.
• Excessive Medial Eminence Resection: Leads to Hallux Varus.
• Ignoring Lesser Toe Deformities: Must address 2nd toe problems at the same time.
• Not Consenting for Recurrence: Patients must understand 10-20% recurrence rate.
• Not Assessing for RA/Gout: Inflammatory HV needs systemic management too.