Metatarsus adductus, also known as metatarsus varus, is a common foot deformity noted at birth that causes the front half of the foot, or forefoot, to turn inward. Metatarsus adductus may also be referred to as "flexible" (the foot can be straightened to a degree by hand) or "non-flexible" (the foot cannot be straightened by hand).
The cause of metatarsus adductus is not known. It occurs in approximately one out of 1,000 to 2,000 live births.
Other causal factors include the following:
Babies born with metatarsus adductus rarely need treatment as they grow. They may, however, be at increased risk for developmental dysplasia of the hip (DDH) is a condition of the hip joint in which the top of the thigh (femur) slips in and out of its socket, because the socket is too shallow to keep the joint intact.
A physician makes the diagnosis of metatarsus adductus with a physical examination. During the examination, the physician will obtain a complete birth history of the child and ask if other family members were known to have metatarsus adductus.
Diagnostic procedures are not usually necessary to evaluate metatarsus adductus. However, x-rays (a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film) of the feet are often done in the case of non-flexible metatarsus adductus.
An infant with metatarsus adductus has a high arch and the big toe has a wide separation from the second toe and deviates inward. Flexible metatarsus adductus is diagnosed if the heel and forefoot can be aligned with each other with gentle pressure on the forefoot while holding the heel steady. This technique is known as passive manipulation.
If the forefoot is more difficult to align with the heel, it is considered a non-flexible, or stiff foot.
Specific treatment for metatarsus adductus will be determined by your child's physician based on:
The goal of treatment is to straighten the position of the forefoot and heel. Treatment options vary for infants, and may include:
Studies have shown that metatarsus adductus may resolve spontaneously (without treatment) in the majority of affected children.
Your child's physician or nurse may instruct you on how to perform passive manipulation exercises on your child's feet during diaper changes. A change in sleeping positions may also be recommended. Suggestions may include side-lying positioning.
In rare instances, the foot does not respond to the stretching program, long leg casts may be applied. Casts are used to help stretch the soft tissues of the forefoot. The plaster casts are changed every one to two weeks by your child's pediatric orthopaedist.
If the foot responds to casting, straight cast shoes may be prescribed to help hold the forefoot in place. Straight last shoes are made without a curve in the bottom of the shoe.
For those infants with very rigid or severe metatarsus adductus, surgery may be required to release the forefoot joints. Following surgery, casts are applied to hold the forefoot in place as it heals.
Long leg casts are applied from the upper thigh to the foot. These casts are used for thigh, knee, or lower leg fractures. They can also be used with knee dislocations or after surgery on the leg or knee area.
Contact your child's physician if your child develops one or more of the following symptoms:
Metatarsus adductus is a common problem that can be corrected. Regardless of how much the forefoot turns inward, starting treatment immediately after birth improves your child's prognosis.