Metatarsus adductus

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).

Causes

The cause of metatarsus adductus is not known. It occurs in approximately one out of 1,000 live births and affects girls and boys equally. One or both feet may be affected.

Other associated factors include the following:

• Family history of metatarsus adductus
• Position of the baby in the uterus, especially with breech presentations

Babies born with metatarsus adductus may also be at increased risk of having an associated hip condition known as developmental dysplasia of the hip (DDH). 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. Learn more about hip displaysia.

Diagnosis

A healthcare provider makes the diagnosis of metatarsus adductus with a physical examination. During the examination, the provider 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 curved foot that is shaped like a kidney bean. The toes and forefoot are pointed 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.

Treatment:

Specific treatment for metatarsus adductus will be determined by your child's physician based on:

• Your child's age, overall health, and medical history
• The extent of the condition
• Your child's tolerance for specific medications, procedures, or therapies
• Expectations for the course of the condition
• Your opinion or preference

The goal of treatment is to straighten the position of the forefoot and heel. Treatment options vary for infants, and may include:

• Observation, for those with a supple, or flexible, forefoot
• Stretching or passive manipulation exercises
• Casts

Studies have shown that metatarsus adductus often resolves spontaneously (without treatment) in the majority of affected children.

Your child's healthcare provider may instruct you on how to perform passive manipulation exercises on your child's feet throughout the day.

If 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 orthopedic provider.

If the foot responds to casting, straight last 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, and the shoes are connected with a bar that holds the feet pointed outward.

What are long leg casts? 

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.

Cast care instructions:

• Keep the cast clean and dry
• Check for cracks or breaks in the cast
• Rough edges can be padded to protect the skin from scratches
• Do not scratch the skin under the cast by inserting objects inside the cast
• Use a hairdryer placed on a cool setting to blow air under the cast and cool down the hot, itchy skin. Never blow warm or hot air into the cast
• Do not put powders or lotion inside the cast
• Cover the cast while your child is eating to prevent food spills and crumbs from entering the cast
• Prevent small toys or objects from being put inside the cast
• Elevate the cast above the level of the heart to decrease swelling

When to call your child's physician: 

Contact your child's physician if your child develops one or more of the following symptoms:

• Fever greater than 101° F
• Increased pain
• Increased swelling above or below the cast
• Complaints of numbness or tingling
• Drainage or foul odor from the cast
• Cool or cold toes