Description

• Metatarsus adductus (MA) is rotational lower limb abnormality and a common pediatric foot deformity in which the metatarsals are deviated medially on the cuneiform bone.
• MA is thought to be acquired in utero due to positioning and results in intoeing.
• It is commonly referred to as being “pigeon toed.”
• Classified as being flexible, semiflexible, or rigid
• Flexible MA is the most common form of MA and resolves spontaneously in 95% of cases.
• Cases of flexible MA that do not resolve spontaneously or cases of semiflexible/rigid MA may require serial casting or surgery.

Epidemiology

Incidence

• MA occurs in 1 to 2 children per 1,000 live births.
• Left foot affected more frequently than right
• More common in males

Etiology and Pathophysiology

• Etiology of MA is not yet fully understood; most commonly attributed to increased intrauterine pressure, supported by increased incidence in twin gestation
• Small association with developmental dysplasia of the hip (DDH), approximately 2% of cases (1)[C]
• Osseous abnormality or abnormal muscle attachments have also been proposed as possible etiologies.

Genetics

• No known genetic link in most cases of MA
• One case study of MA in brothers with Aarskog-Scott syndrome
• Higher incidence if sibling has MA

Risk Factors

• First pregnancy
• Twin gestation
• Oligohydramnios

General Prevention

No known preventative measures for MA

Commonly Associated Conditions

• There is a small association with DDH, likely related to intrauterine pressure.
• One study found that 29–35% of patients undergoing surgery for hallux valgus deformity (bunion) have MA.
• Hammertoe, medial tibial torsion, and torticollis have been associated with MA, but no long-term studies have confirmed this.