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Condition/Disorder Synonyms

  • Hallux valgus

  • Bunion

ICD-9-CM Code

  • 735.0 Hallux valgus (acquired)

ICD-10-CM Code

  • M20.10 Hallux valgus (acquired), unspecified foot

Preferred Practice Pattern

Key Features


  • Valgus deviation (lateral, abduction) of the great toe (hallux) and varus deviation of the 1st metatarsal

  • Some rotation (valgus rotation) at the 1st metatarsal also possible

  • Static subluxation of 1st metatarsophalangeal joint (MTP)

  • Tissue surrounding 1st metatarsal joint may be inflamed and tender

  • “Bump” on medial side of the 1st toe partly due to

    • Inflammation of the bursal sac

    • Osseous (bony) anomaly on the mesophalangeal joint (where first metatarsal bone and hallux meet)

    • Large part of the bump tends to be the head of the 1st metatarsal, as it deviates medially in relation to the phalange

Essentials of Diagnosis

  • Diagnosis usually made by clinical examination or x-ray

  • Can be an independent diagnosis, not associated with disease process

General Considerations

  • Important to correct forefoot weight distribution following surgical correction or another bunion will develop

  • Need to address barefoot walking or improper footwear


  • Most common in women: male-female ratio 9:12

  • 22 to 36% if cases are in adolescents2

  • Hereditary component

  • Poor footwear: improper fit, pointed toe, narrow forefoot

  • Dancers at higher risk

Clinical Findings

Signs and Symptoms

  • Irritated skin around bunion

  • Pain in 1st metatarsal with walking

  • Paresthesia in 1st metatarsal

  • Global ligamentous laxity

  • Joint redness and pain

  • Shift of big toe towards others

  • Depression of 2nd metatarsal with possible formation of hammer toe

  • Callus and blister formation around bunion

  • Difficulty finding shoes with proper fit

  • Lateral subluxation of the flexor hallucis longus (FHL) muscle2

Functional Implications

  • Pain with standing

  • Pain in affected toe with ambulation

  • Inability to wear stiff shoes

  • Need to wear larger shoes to accommodate bunion

  • Altered gait pattern and mechanical issues of the forefoot

Possible Contributing Causes

  • Pes planus (flat feet)

  • Excessive pronation

  • Genu valgus

  • Limited dorsiflexion (tight heel cord)

  • Abnormal bone structure

  • Arthritis

  • Leg length discrepancy

  • Congenital Grebe syndrome

  • Neurologic conditions, including

    • Cerebral palsy

    • Multiple sclerosis

    • Charcot-Marie-Tooth

    • Marfan syndrome

    • Down syndrome

Differential Diagnosis

  • Hallux rigidus

  • Sesamoiditis

  • Hammer toe

  • Metatarsalgia

  • Metatarsal stress fracture

Means of Confirmation or Diagnosis


  • X-ray

Findings and Interpretation

  • Increased angle between first and second metatarsals



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