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A healthy 35-year-old woman has had "bunion pain" for more than 3 years. On examination, she has moderate lateral deviation of the hallux (Figure 217-1), a mildly contracted second digit, tenderness at the medial prominence, painless first metatarsophalangeal (MTP) range of motion, and a callus under the second metatarsal head. Radiographs (Figure 217-2) show medial angulation of the first metatarsal and lateral deviation of the hallux.
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The patient was referred to podiatry for surgical correction of the bunion deformity. After surgery, she was placed in a post-op shoe for 4 weeks. She progressed to a regular shoe over the next month.
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Bunion deformity is characterized by the presence of a medial prominence at the first MTP joint, caused by a laterally angulated hallux on a medially angulated first metatarsal. The deformity causes irritation in a tight shoe and/or pain in the MTP joint. Initial therapy can be conservative with correction of footwear and application of padding. Most of the surgical procedures correct the misalignment, rather than shave the medial prominence.
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Hallux valgus, hallux abducto valgus, metatarsus adductovarus.
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ETIOLOGY AND PATHOPHYSIOLOGY
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Bunion deformities are caused by multiple factors:
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Genetic and hereditary factors.
Abnormal biomechanics (most common) such as limb length discrepancy, hypermobility/ligament laxity, flatfoot deformity, malaligned skeletal structures, and ankle equinus.
Inflammatory arthritis such as rheumatoid arthritis (Figure 217-3).
Neuromuscular diseases.
Ill-fitting shoes.
Trauma.
Iatrogenic causes.
Neoplasm.
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Underlying flatfoot, metatarsus adductus (global medial angulation of the metatarsals) and equinus.
Family history of bunion deformity.
Ligamentous laxity.
Having to wear dress shoes (narrowed toe shoes).
Female gender.
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The diagnosis of hallux abducto valgus deformity is made clinically and radiographically.
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