Bunionette 

The term "tailor's bunion" initially described an acquired lesion that caused chronic pain and swelling over the lateral aspect of the fifth metatarsal head (see the images below). 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 a painful prominence on the lateral aspect of the fifth metatarsal head. While 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 metatarsal.^{[2, 3]}

Frequency

US

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

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

Causes can be extrinsic or intrinsic.^[4] 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 metatarsal shaft, abnormal intermetatarsal ligament insertion with prominence of the fifth metatarsal, brachymetatarsia, or primary hypertrophy of the metatarsal head. Congenital splayfoot is a more generalized congenital predisposing lesion. Iatrogenic causes can occur as a result of failed adjacent metatarsal surgery or residual malalignments from hindfoot surgery, which cause increased prominence of the fifth metatarsal. Inflammatory arthropathies also can cause bunionette deformities or soft tissue lesions in association with bony problems.

Pathologic lesions include an inflamed bursa overlying the lateral aspect of the metatarsal head, a bony enlargement of the head itself, or an increased intermetatarsal angle between the fourth and fifth metatarsals with secondary medial angulation of the phalanx and abnormal curvature of the fifth metatarsal. Recognition of the varying pathologies is an essential part of surgical management.

Presenting symptoms usually include painful keratoses over the lateral aspect of the metatarsal head, but they also may be present on the plantar and dorsal aspects. Medial deviation of the fifth phalanx with some rotation is frequently seen. Differentiating whether the patient is truly having pain or whether the patient just finds his or her foot cosmetically unacceptable is important. Assessing whether the deformity is fixed or correctable also is important.^[5]

Examination should assess other foot deformities, such as hallux valgus, planovalgus foot deformity, and equinus, and the presence of neuritic symptoms or systemic arthropathy.

Surgery is performed when symptoms of an unacceptable degree are not relieved by conservative treatments, such as shaving the callous or wearing wider shoes, silicon pads, softer shoe coverings, or sandals.

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.

The normal fourth and fifth intermetatarsal angle is approximately 6.2°, and the normal fifth MTP angle is about 10°. Pathological angles are in the range of 10° for the intermetatarsal angle and 16° for the MTP angle.

Absolute and relative contraindications to surgery include pure cosmetic deformity, vascular impairment, severe diabetic arthropathy, significant infection with bony involvement, psychiatric disorders that prevent appropriate postoperative compliance, severe osteoporosis, and severe progressive erosive arthropathies.

Some of these contraindications apply to specific reconstructive procedures. For example, severe refractory deformities, inflammatory conditions, and infected neuropathic arthritic or failed surgical procedures may require treatment with ablative rather than reconstructive procedures.