SUMMARY

• • Hallux Valgus, commonly referred to as a bunion, is a complex valgus deformity of the first ray that can cause medial big toe pain and difficulty with shoe wear.

  • Diagnosis is made clinically with presence of a hallux that rests in a valgus and pronated position. Radiographs of the foot are obtained to identify the severity of the disease and for surgical planning.

  • Treatment can be nonoperative with shoe modifications for mild and minimally symptomatic cases. Surgical management is indicated for progressive deformity and difficulty with shoe wear.  

• EPIDEMIOLOGY

  • Demographics

    • more common in women

  • Risk factors

    • intrinsic

      • genetic predisposition

        • 70% of pts with hallux valgus have family history

      • increased distal metaphyseal articular angle (DMAA)

      • ligamentous laxity (1st tarso-metatarsal joint instability)

      • convex metatarsal head

      • 2nd toe deformity/amputation

      • pes planus

      • rheumatoid arthritis

      • cerebral palsy

    • extrinsic

      • shoes with high heel and narrow toe box

ETIOLOGY

• Two forms exist

  • adult hallux valgus

  • adolescent & juvenile hallux valgus

• Pathoanatamy

  • valgus deviation of phalanx promotes varus position of metatarsal

  • the metatarsal head displaces medially, leaving the sesamoid complex laterally translated relative to the metatarsal head

  • sesamoids remain within the respective head of the flexor hallucis brevis tendon and are attached to the base of the proximal phalanx via the sesamoido-phalangeal ligament

  • this lateral displacement can lead to transfer metatarsalgia due to shift in weight bearing

  • medial MTP joint capsule becomes stretched and attenuated while the lateral capsule becomes contracted

  • adductor tendon becomes deforming force 

     

    • inserts on fibular sesamoid and lateral aspect of proximal phalanx

  • lateral deviation of EHL further contributes to deformity

  • plantar and lateral migration of the abductor hallucis causes muscle to plantar flex and pronate phalanx

  • windlass mechanism becomes less effective

    • leads to transfer metatarsalgia

• Associated conditions

  • hammer toe deformity

  • callosities

  • pes planus

    • associated with deformity progression 

       

• Juvenile and Adolescent Hallux valgus 

  • factors that differentiate juvenile / adolescent hallux valgus from adults

    • often bilateral and familial

    • pain usually not primary complaint

    • varus of first MT with widened IMA usually present

    • DMAA usually increased

    • often associated with flexible flatfoot

  • complications

    • recurrence is most common complication (>50%), also overcorrection and hallux varus

ANATOMY

• Pathoanatomy cascade

PRESENTATION

• Symptoms

  • presents with difficulty with shoe wear due to medial eminence

  • pain over prominence at MTP joint

  • compression of digital nerve may cause symptoms

• Physical exam

  • Hallux rests in valgus and pronated due to deforming forces illustrated above 

     

  • examine entire first ray for

    • 1st MTP ROM

    • 1st tarsometatarsal mobility

    • callous formation

    • sesamoid pain/arthritis

  • evaluate associated deformities

    • pes planus

    • lesser toe deformities

    • midfoot and hindfoot conditions

IMAGING

Radiographs

• views

  • standard series should include weight bearing AP, Lat, and oblique views

  • sesamoid view can be useful

• findings

  • lateral displacement of sesamoids

  • joint congruency and degenerative changes can be evaluated

  • radiographic parameters (see below) guide treatment

  TREATMENT - ADULT HALLUX VALGUS

• Nonoperative

  • shoe modification/ pads/ spacers/orthoses

    • indications

      • first line treatment

    • orthoses more helpful in patients with pes planus or metatarsalgia

• Operative

  • surgical correction

    • indications

      • when symptoms present despite shoe modification

      • do not perform for cosmetic reasons alone

    • technique

      • soft tissue procedure

        • indicated in very mild disease in young female (almost never)

      • distal osteotomy

        • indicated in mild disease (IMA < 13)

      • proximal or combined osteotomy

        • indicated in more moderate disease (IMA > 13)

      • 1st TMT arthrodesis

        • arthritis at TMT joint or instability

      • fusion procedures

        • indicated in severe deformity/spasticity/arthritis 

           

      • MTP resection arthroplasty

        • only indicated in elderly patients with low functional demands

TREATMENT - JUVENILE AND ADOLESCENT HALLUX VALGUS

TECHNIQUES

• Soft Tissue Procedures

  • modified McBride

    • indications 

      • goal is to correct an incongruent MTP joint (phalanx not lined up with articular cartilage of MT head). Usually done in patients with

        • a HVA less than 25 degrees 

        • IMA deformity less than 15 degrees

        • usually in patient 30-50 years of age

      • rarely appropriate in isolation

        • usually performed in conjunction with

          • medial eminence resection

          • MT osteotomy

          • 1st TMT arthrodesis (Lapidus procedure)

    • technique

      • includes

        • release of adductor from lateral sesamoid/proximal phalanx

        • lateral capsulotomy

        • medial capsular imbrication

        • (original McBride included lateral sesamoidectomy)

• Metatarsal Osteotomies

  • distal metatarsal osteotomy

    • indications

      • mild disease (HVA 15-25°, IMA < 13°) 

         

      • unable to correct pronation deformity  

         

    • distal metatarsal osteotomies include

      • Chevron 

         

      • biplanar Chevron (corrects DMAA) 

      • Mitchell

      • may be combined with proximal phalanx osteotomy (Akin-medial closing wedge osteotomy)

  • proximal metatarsal osteotomy 

     

    • indications

      • moderate disease (HVA >40°, IMA >13°)

    • proximal metatarsal osteotomies include

      • crescentic osteotomy

      • Broomstick osteotomy

      • Ludloff

      • Scarf 

  • double (proximal and distal) osteotomy

    • indications

      • severe disease (HVA 41-50°, IMA 16-20°)

  • first cuneiform osteotomy

    • indications

      • severe deformity in young patient with open physis

• Proximal phalanx osteotomies

  • Akin osteotomy 

     

    • indications

      • hallux valgus interphalangeus

      • congruent joint with DMAA <10°

      • as a secondary procedure if a primary procedure (e.g., chevron or distal soft-tissue procedure) did not provide sufficient correction due to a large DMAA or HVI

      • some authors perform Akin together with/at the time of proximal osteotomy+distal soft tissue correction because this results in progressive increase in HVI

• Fusion procedures

  • Lapidus procedure (1st metatarsocuneiform arthrodesis with modified McBride) 

     

    • indications

      • severe deformity (very large IMA)

      • arthritis at 1st TMT

      • metatarsus primus varus

      • hypermobile 1st TMT joint 

      • concomitant pes planus

  • MTP Arthrodesis

    • indications are hallux valgus in

      • cerebral palsy

      • Down's syndrome

      • Rheumatoid arthritis

      • Gout

      • Severe DJD

      • Ehler-Danlos 

• Resection arthroplasty

  • proximal phalanx (Keller) resection arthroplasty

    • indications

      • largely abandoned

      • rarely indicated in some elderly patient with reduced function demands

• Surgical Indications for Specific Conditions
  Juvenile/Adolescent with open physis	First cuneiform osteotomy
  Hypermobile 1st MT	Lapidus procedure
  DJD	MTP arthrodesis
  Skin breakdown	Simple bunionectomy with medial eminence removal
  Gout	MTP arthrodesis
  Recurrence with pain in 1st TMT joint	Lapidus procedure
  Rheumatoid arthritis	MTP arthrodesis
  Down's syndrome, CP, Ehler-Danlos	MTP arthrodesis

COMPLICATIONS

• Recurrence 

   

  • most common cause of failure is insufficient preoperative assessment and failure to follow indications 

    • e.g., failure to recognize DMAA > 10°

    • inadequate correction of IMA

    • e.g., failure to do adequate distal soft tissue realignment

  • more common in juvenile/adolescent population

  • noncompliant patient that bears weight

  • rounded shape to the first metatarsal head

  • residual tibial sesamoid lateral displacement

  • increased preoperative IMA and HVA

  • failure to perform a lateral release of the adductor hallucis tendon 

  • associated with incomplete reduction of the sesamoids 

     

• Avascular necrosis 

   

  • medial capsulotomy is primary insult to blood flow to metatarsal head

  • distal metatarsal oseotomy and lateral soft tissue release inconjunction do not increase risk for AVN (Chevron plus lateral release thought to increase risk in the past)

    • treat with MTP arthrodesis with or without structural graft  

       

• Dorsal malunion with transfer metatarsalgia

  • due to overload of lesser metatarsal heads

  • risk associated with shortening of hallux MT

    • Lapidus

    • proximal crescentric osteotomies

• Hallux Varus 

   

  • caused by 

     

    • overcorrection of 1st IMA

    • excessive lateral capsular release with overtightening of medial capsule

    • overresection of medial first metatarsal head 

       

    • lateral sesamoidectomy 

       

• Cock up toe deformity
  • due to injury of FHL
  • most severe complication with Keller resection

  • due to injury of FHL

  • most severe complication with Keller resection

• 2nd MT transfer metatarsalgia 

   

  • often seen concomitant with hallux valgus

  • can occur secondary to malpositioning of MTP fusion 

     

  • shortening metatarsal osteotomy (Weil) indicated with extensor tendon and capsular release 

     

• Neuropraxia 

   

  • Painful incisional neuromas after bunion surgery frequently involve the medial dorsal cutaneous nerve (a terminal branch of the superficial peroneal nerve). 

     

    • It is most commonly injured during the medial approach for capsular imbrication or metatarsal osteotomy.