Hallux Valgus

Western Health Orthopaedic Registrar presentation – Hallux Valgus Rigidus By Dr Marc Friso

• Bunion
  • Derived from latin word Bunio meaning Turnip.
  • Consists of :     
    • 1. Medial eminence
    • 2. Bursal sac communicating with joint
    • 3. Callosity of skin
• Condition in which there is
  • static subluxation if the first MTPJ
  • lateral deviation of the great toe
  • medial deviation of the first metatarsal
• It is not a simple deformity but complex deformity of the first ray
• Frequently associated with deformity and symptoms of the lesser toes

Epidemiology

• Almost exclusively seen in the shoe wearing population-33% with shoes and 1.9% without.
• Females : Males – 9:1.

Aetiology

• Multifactorial
• Strong hereditary predisposition
  • Occasionally only isolated exostosis of the first MTPJ
  • Maternal transmission
  • hypermobility
• Predisposing factors include;
  • Ill fitting stylish shoes
    • Where shoes are not worn incidence equal among men & women,
    • where shoes are worn, women>men 3:1 to 15:1
  • Local Anatomic Factors
    • Bone
      • Excessive length of first ray
      • Excessive rounding of first metatarsal head or incongruous surface
      • Obliquity of the first Metatarso- Cunieform joint
        • excessive valgus tilt
      • Amputation of second toe
      • Pes planus (pronated flatfoot)
    • Soft tissue
      • Achilles tendon contracture
        • limits dosiflexion and ext rotation of foot occurs with medial force on foot increased.
      • Tibialis Posterior – abnormal insertion
  • General Factors
    • Neurogenic imbalance
      • ie Cerebral Palsy, Spinal dysrhaphism, spinal cord tumor
    • Rheumatoid Arthritis
      • pes valgus with pronated forefoot and increased valgus moment at toe off.
    • Generalized ligamentous laxity

Anatomy

• Anatomical Features
  • Sesamoid bones (within tendons of flexor hallucis brevis, lie in grooves on plantar surface of 1st metatarsal head
  • Plantar plate – condensation of FHB, AbH, AdH, plantar fascia
  • There are no tendon insertions onto metatarsal head, its position is influenced by position of proximal phalanx
  • Base of 1st MTP – articulates with medial cuneiform – may be lax in some cases

Pathogenesis / Pathology

Biomechanics:

• Great toe stabilizes the medial foot via the Windlass effect of plantar aponeurosis.
• As body passes over the great toe the PP dorsiflexes and then the Planter aponeurosis tightens and depresses the first metatarsal
  • 50 % of weight through the first metatarsal.
• If the MTPJ subluxes laterally then weight is traasferred laterally via the other metatarsal heads
• Must correct this mechanism in surgery for Hallux Valgus

Pathooanatomy:

• Stable MTP joints have flatter articulations
  • Rounded articulations can progress to hallux valgus deformity
  • When articulation is rounded, progressive hallux valgus can develop
• As phalanx deviates laterally, places pressure against metatarsal head, increasing metatarsal – first phalanx angle
• Medial joint structures become attenuated, lateral joint structures contract
• Sesamoids generally remain in place (anchored to adductor hallucis), other structures rotate around joint
• As adductor tendon rotates, becomes more plantar & no longer stabilizes metatarsal head, & becomes deforming force & pronates proximal phalanx
• FHL pulls phalanx laterally
• As deformity progresses, great toe pronates & sesamoid displaces laterally
• Cresta (ridge that stabilizes the sesamoids) is worn down and the lateral sesamoid uncovered
• Final result is hallux can no longer carry its share, & weight is transferred laterally to lesser toe metatarsal heads
• Congruous MTP
  • when articular surface of proximal phalanx is parallel to surface of metatarsal head – this is relatively stable
• Incongruous MTP
  • occurs when articular surfaces of proximal phalanx & metatarsal head are no longer parallel – this is relatively unstable

Pathophysiology

• HVA < 35
  • no pronation of great toe
• HVA > 35
  • great toe pronates
  • moves abductor hallucis plantarward
  • leaving medial capsular ligament as the only restraining medial structure
  • there is now no opposition to pull of ADDuctor Hallucis
    • which further pulls toe into valgus, further stretching the medial capsule
  • FHL, FHB, EHL worsen the valgus pull

Classification

• 1. Adult acquired
• 2. Adolescent
• 3. Rheumatoid

History

• • History to ascertain main complaint.
• − Pain
  • Location
    • − bunion
  • The dorsum -osteophyte
  • The plantar aspect from sesamoids
  • The inflammed bursa
  • Metatarsalgia
• − Determine patient’s main problem → cosmesis, transfer metatarsalgia, second toe deformity, shoe wear, pain

Examination

• Questions to answer
  • Severity
    • HV angle
    • Pronation
  • Reducible or fixed
  • OA of MTP, IP
  • Hypermobile TMT
    • Look for callosity under 2nd MT head
  • Ankle equines deformity

Shoe wear/fit

Look

• Standing
  • Front
    • General alignment
    • Hallux valgus
      • Degree
      • pronation
    • Bunion
    • Lesser toe abnormalities
    • skin
  • Side
    • Pes planus
    • Longitudinal arch
  • Behind
    • Foot in standing posture
    • Posture of forefoot in relation to hindfoot
• GAIT
• Sitting
  • Dorsum
    • Medial eminence – redness/ulceration
    • Ingrown toenail
  • Plantar
    • Callosities under metatarsal heads

Feel

• Tenderness
• Dorsal osteophyte 1st MTPJ
• tenderness over medial aspect of MTP joint
  • occurs from irritation of dorsal cutaneous nerve
  • may occur from hypertrophic bursa

Move

• Hallux valgus reducible
• ROM
  • TA tightness
  • ankle,
  • subtalar,
  • midtarsal,
  • TMTJ
• Pain
• Laxity / stable
• ROM
  • MTPJ
    • Reducible
    • Irritable
    • crepitus, loss of motion and pain
• IPJ
  • Quantify range
  • ? irritable

Special

• Neurovascular status
• Sensation
  • Medial / lateral side of 1st toe
  • Medial side of 2nd toe
• Ligamentous laxity

Investigations

Standing Radiographs (AP , lat , oblique views)

• Angles

Angle	Normal	Importance
HVA (hallux valgus angle)	<15
IMT (Intermetatarsal angle)	<9
DMMA (Distal metatarsal articular angle)	<10°
Hallux Valgus Interphalangeus	< 10°
Metatarsus Primus Varus	< 25

• High DMMA = congruent joint = osteotomy needed not lateral release
• Congruency of first MTPJ
  • Noncongruency = lateral release
• Sesamoid congruency
  • determined relative to a line that bisects the long axis of the first metatarsal shaft

Grade	Description
1	< 50% overlap the reference line
2	> 50% overlap the reference line
3	complete displacement beyond reference line

• Size of medial eminence
• First MTPJ OA
• IPJ OA
• Obliquity of Metatarsocuneiform joint
• Hypermobility signs
  • Plantar gapping
  • 2nd MT cortical thickening

Treatment

Primary goals:

1. Reduce pain
2. Restore articular congruency of first ray
3. Restore alignment of first ray relative to the lateral part of foot

• Patients shoe wear habits essential
• Before surgery only 1/3 of patients wear shoes they want and after surgery only 2/3 are able to wear shoes of choice.
• Surgery should not be done in asymptomatic feet .
• Will fail if predisposing factors not addressed as well .

Need to consider:

• Occupation and athletic pursuits
• Patient expectations
• Failure of non-op measures
• Age
• Physical findings
• Radiographic abnormalities
• Neurovascular status

Non-Operative

• ELPOMI
  • Wide toe box and broad shoe
  • Low heels
  • Avoid seams
  • Soft expandable upper
  • Premetatarsal bar and medial arch support
  • Podiatrist for callosities.
  • Bunion splint
  • Toe spacer
  • Orthosis with medial arch
  • Shoe stretching

Operative

• Indications
  • Pain
  • Shoewear difficulties
  • Ulceration (neuropathic)
  • HVA > 20°
  • IMA > 10°
  • Failed nonoperative management
• Contraindications
  • Cosmetic
  • Active Athlete
  • Unrealistic expectations
  • vascular insufficiency
  • neuropathic foot
  • Children with open physis
  • Spastic muscular condition
  • Severely pronated foot (high rate of recurrance)
• Ideal hallux valgus surgery
  • 1. Correction of the IMT and HV angles
    • a. Minimal shortening
    • b. Adequate stability
  • 2. Creation of a congruent 1st MTPJ with sesamoid realignment
  • 3. Resection of the medial eminence parallel to and flush with the MT shaft
  • 4. Retention of function and ROM of the 1st MTPJ
  • 5. Maintenance of normal weight bearing mechanics

Algorithm

Severity	Congruent	Noncongruent
Mild HV < 20 IMT <10	* Chevron osteotomy * Mitchell’s osteotomy	* Distal soft tissue procedure ~ (Adductor Hallucis, intermetatarsal lig. & lateral capsule) * Chevron osteotomy * Mitchell’s osteotomy
Moderate HV <40 IMT <20	Scarf + Akin + Distal soft tissue procedure	Scarf + Akin + Distal soft tissue procedure
Severe HV >40 IMT >20	Scarf + Akin + Distal soft tissue procedure	Scarf + Akin + Distal soft tissue procedure

• OA = arthrodesis
  • Fusion
• Hypermobile 1st MTPcuneiform
  • this joint should be fused, & distal soft tissue procedure performed.
• Keller in low demand elderly pt
• Juvenille Hallux Valgus
  • Delay surgery until skeletal maturity
  • ↑ DMAA
  • ↑ recurrence

Complications

• Deformity
  • Overcorrection
  • Hallux Varus
  • Negative IM angle
  • Excess MT head resection
  • Lateral sesamoid excision
• Recurrence
  • Failure to include MT osteotomy
  • Inadequate lateral release
  • Poor quality medial tissue
• Cock up deformity
• Pain
  • Transfer metatarsalgia
  • Shortening
  • Dorsiflexion
• Stiffness / OA
• AVN
  • 0 to 20% for chevron, 8 to 12% for Mitchell

Bunion Procedures

1. Distal Soft Tissue Procedures.

• Modified McBride

2. Distal Bony Procedures.

• Chevron Osteotomy
• Mitchell Osteotomy
• Wilsons Shaft Osteotomy

3. Proximal Metatarsal Osteotomy

• Scarf

4. Proximal Phalangeal Osteotomy.

• Akin Procedure

5. Kellers Resection Arthroplasty.

6. Arthrodesis of 1st MTPJ

7. Arthroplasty of 1st MTPJ

8. Metatarsocunieform Arthrodesis (1st TMT Lapidus)