Metatarsus adductus is a condition in which the front half of your child’s foot (forefoot) has a noticeable curved shape. It is present at birth and may be either flexible or rigid.
In most cases, your child’s feet will naturally straighten as they grow up, but this is not always the case. Treatment is often required to improve your baby’s prognosis and help them meet developmental milestones.
Causes
Metatarsus adductus is the most common foot problem in babies. It causes the front part of the feet to turn inward (pigeon toes). It affects one or both feet. Most infants grow out of the condition as they get older. Babies born with the condition may be at risk for developing hip dysplasia, a disease of the hip in which the top of the thighbone (femur) slips in and out of the socket that holds it.
Healthcare providers diagnose metatarsus adductus through a physical exam of the foot. They look for a high arch and a visibly curved, separated big toe. They also look for the characteristic adduction of the 5th metatarsal bones at the tarsometatarsal joint (Lisfranc joint).
Some infants with metatarsus adductus are flexible. This means they can be straightened by applying gentle pressure to the forefoot while holding the heel steady. They can also be straightened by stretching exercises.
Others are stiff and don’t move easily with manual force. This type of metatarsus adductus is called nonflexible. It can be diagnosed by seeing if the forefoot can be aligned with the heel by applying force to the foot.
It is believed that this foot condition is caused by intra-uterine positioning during development that leads to abnormal adduction of the forefoot at the tarsometatarsal joints. It may be aggravated by early footwear that places excessive stress on the feet or in some cases, the condition can resolve itself as children grow and develop more strength in the forefoot and in their muscles. Surgical management is indicated for patients who cannot be corrected with stretching or serial casting. If left untreated, metatarsus adductus can progress to hallux valgus or skewfoot.
Symptoms
Children with metatarsus adductus may walk and run with their feet turned inward, a condition known as in-toeing or being “pigeon-toed.” They typically have high arches, and a wide gap between the big toe and second toe. In some cases, a child with MTA also has a clubfoot deformity (when the arch of the foot collapses), or tarsal coalition (where two or more bones in the feet are abnormally connected).
The cause of MTA is unknown, although it’s thought that a baby’s position in the mother’s womb plays a role. Women who drink alcohol or smoke during pregnancy are at a higher risk of having a baby with MTA. The condition is most commonly diagnosed in infants and young children, although it can occur in adults. Boys are more likely to be affected than girls. Geographic location may play a role in the incidence of MTA, but more research is needed.
MTA is usually diagnosed through a physical exam by your child’s healthcare provider. They will look at the way your child walks, and see if their feet are straight or if they have a large gap between the big toe and the second toe. They may use the ‘V’ finger test, where they cup the heel of your child’s foot in the ‘V’ shape formed by the index and middle fingers. If the heel moves towards the middle finger, it’s likely that your child has MTA. X-rays may be used to confirm the diagnosis, and help rule out other conditions like a clubfoot or tarsal coalition.
Most children with flexible MTA do not need any treatment, as the condition usually improves on its own as they grow older. Your child’s healthcare provider may recommend passive manipulation, which involves gently pushing your child’s forefoot to align it with the heel. If the forefoot is easily aligned, your child has flexible MTA. In some cases, your child’s doctor or nurse may suggest passive manipulation exercises during diaper changes or sleeping positions. In rare cases, surgery may be needed if the MTA is very rigid.
Diagnosis
In metatarsus adductus, the front half of your child’s foot (forefoot) bends or turns inward. This deformity is usually noticeable at birth. It may be flexible, which means it can be straightened to a degree by hand, or rigid, which means it can’t. It is more common in firstborn children.
Your child’s healthcare provider can identify metatarsus adductus during a physical exam. They will look for a curved shape in the foot and toes, and will also check if the foot is stiff or rigid. Your child’s healthcare provider will also ask you about your child’s family history, since this condition is sometimes inherited.
Babies who are born with metatarsus adductus rarely need treatment, as the condition often corrects itself as they grow. However, this condition can be a risk factor for developmental hip dysplasia of the hip (DDH), a condition in which the top of the thigh bone slips out of its socket.
A physician can diagnose metatarsus adductus by doing a physical examination and taking a complete birth history. They will examine your child’s feet, paying special attention to the position of the big toe and how it compares with the other toes. A doctor can also perform X-rays of the feet to confirm the diagnosis.
For children with flexible metatarsus adductus, they can often be treated by gently pressing on the forefoot while holding the heel steady. This is called passive manipulation. This is a safe technique that can be used by a trained medical professional. In some cases, children with flexible metatarsus adductus may have to be manipulated more than once to straighten their feet.
If your child has a non-flexible form of metatarsus adductus, their healthcare provider may recommend serial casting. Casts are made to help support the foot as it heals. For very severe forms of the condition, surgery may be needed to release the forefoot joints and align the bones of the foot. The procedure is typically done by a pediatric orthopedic surgeon. Surgical corrections may include lateral column shortening and open-wedge osteotomies of the first cuneiform.
Treatment
The condition causes the front of the child’s foot and toes to curve or deviate inward. It may be mild or severe. Some children grow out of the curved foot shape on their own by their first birthday without treatment. Others need mild treatment to straighten their feet.
A healthcare provider can diagnose the condition by doing a physical examination. They can gently manipulate the child’s foot to see if it is flexible or rigid. They may also use imaging tests like X-rays to get a better view of the bones and joints in the foot.
Many babies with metatarsus adductus can be treated with stretching exercises, shoe gear, braces, or orthoses (shoe inserts). For very flexible cases serial casting can be used to reduce the foot deformity. This is done by putting plaster on the foot to reduce the curvature. Then it is removed and replaced after a week to continue reducing the deformity.
Rigid metatarsus adductus is diagnosed when the heel and forefoot cannot be aligned with each other with gentle pressure on the foot. The deformity is more difficult to correct than flexible metatarsus adductus.
If a child’s metatarsus adductus does not improve by their first birthday, their healthcare provider may recommend they be seen by a pediatric orthopaedist. These doctors specialize in treating problems of the skeletal system, including the bones, muscles, ligaments and tendons.
There is a good chance that children who do not have metatarsus adductus treated by their first birthday will need surgery to straighten their foot. Surgical treatments include various procedures to reshape the foot. These procedures can involve cutting and fixing the bone in a straighter position or soft tissue releases or transfers to release tension on the tendons. In very severe cases, the surgeon may have to remove the short first ray of the foot, which is known as a tarsometatarsal fusion. This procedure is successful in most cases. However, some children will have a permanent short first ray and will need ongoing treatment to prevent problems with the foot. These patients should continue to follow up with their podiatric physician for monitoring.