Bunionette

Updated: Jun 06, 2018
  • Author: Christopher Brown, MBBS, FRCSC, FRACS, FAOrthA; Chief Editor: Vinod K Panchbhavi, MD, FACS  more...
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Overview

Background

The term tailor's bunion (a synonym for bunionette) initially described an acquired lesion that caused chronic pain and swelling over the lateral aspect of the fifth metatarsal (MT) head. These lesions often were present on tailors, whose traditional cross-legged sitting posture on benches resulted in pressure being placed on the lateral side of the foot, leading to the development of painful bunionettes. Davies described the lesion in the English literature in 1949. [1]

A bunionette is defined as a painful prominence on the lateral aspect of the fifth MT head. Although it is not as common as a medial bunion, it is a cause of chronic pain and shoe-fitting problems in individuals whose feet are characterized by a widened forefoot or in those who have a lateral splaying or prominence over the fifth MT. [2, 3, 4]

For patient education resources, see Chronic Pain.

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Pathophysiology

The underlying pathoanatomy and pathophysiology determine procedure selection. No single, universally acceptable procedure exists for all patients.

The pathoanatomy of the bunionette varies with different types of lesions. Usually, there is a component of prominence of the lateral aspect of the fifth metatarsophalangeal (MTP) joint. Stretching and attenuation of the capsule may occur with medial subluxation of the proximal phalanx. Both long flexors and extensors can be medial to the head, leading to a deforming force on the toe that increases with increasing deformity. Rotation of the phalanx also can occur.

Pathologic lesions include the following:

  • Inflamed bursa overlying the lateral aspect of the MT head
  • Bony enlargement of the head itself
  • Increased intermetatarsal angle (IMA) between the fourth and fifth MTs with secondary medial angulation of the phalanx and abnormal curvature of the fifth MT

The normal fourth and fifth IMA is approximately 6.2°, and the normal fifth-MTP angle is about 10°. Pathologic values are in the range of 10° for the IMA and 16° for the MTP angle. Lesions may be conveniently divided into three types (see Imaging Studies).

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Etiology

Causes of bunionette can be extrinsic or intrinsic. [5] Extrinsic causes can be traumatic, either acute or (more commonly) chronic (eg, tailors' working posture, footwear). Intrinsic causes can be related to structural abnormalities, such as congenital lateral bowing of the MT shaft, abnormal intermetatarsal ligament insertion with prominence of the fifth MT, brachymetatarsia, or primary hypertrophy of the MT head. Congenital splayfoot is a more generalized congenital predisposing lesion.

Iatrogenic causes can occur as a result of failed adjacent MT surgery or residual malalignments from hindfoot surgery, which cause increased prominence of the fifth MT. Inflammatory arthropathies also can cause bunionette deformities or soft-tissue lesions in association with bony problems.

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Epidemiology

United States statistics

In Western society, the occurrence of bunionettes is related to narrow footwear on predisposed foot anatomy. The actual incidence is not accurately known, but it is far less of an isolated presenting problem than hallux valgus. However, it is commonly seen in patients who present with hallux valgus secondary to splaying of the forefoot. It may or may not be symptomatic at the same time. Females represent up to 90% of symptomatic patients in some series.

International statistics

Few reports exist in the literature on the incidence in non-Western countries. This is probably a result of less wearing of constricting shoes and, hence, a lower occurrence rate.

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Prognosis

Relief of pain and imporved alignment usually can be obtained with surgical treatment. When cosmesis is the only reason for surgery, satisfaction is less likely because minor symptoms may persist for some months following surgery. Continuing progression of underlying arthropathic disease also may lead to recurrence and unsatisfactory results.

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