What is polydactyly of the foot?
Polydactyly of the foot is a condition where a person is born with more than the usual number of toes. It is a condition that can either be inherited or caused by a genetic mutation. It is more common in those born male than female, and most common in people of African descent.
The extra toes can range from small and non-functional to fully formed with bones and joints. If the extra toes interfere with the function of the foot, wearing shoes, or they cause discomfort, then treatment can involve surgery to remove them.
There are three types of polydactyly of the foot:
- Pre-axial polydactyly: the extra toe is located next to the big toe. This type is seen in 9% of cases.
- Post-axial polydactyly: the extra toe is located next to the little toe. This is the most common type and is seen in 85% of cases.
- Central polydactyly: the extra toe is located in between other toes. This type is seen in 6% of cases.
Development of the hands
Polydactyly develops in the fetus. When hands and feet are first forming, they are shaped like mittens or paddles. Then the fingers or toes form. If an extra finger or toe forms during this process, this causes polydactyly. This may occur randomly (genetic mutation) or because it was inherited.
What are the signs and symptoms of polydactyly?
The main sign of polydactyly of the foot is one or more extra toes. The extra toes may be:
- fully formed digits that function normally
- short, underdeveloped digits that do not function
- small, raised bumps (nubbins)
Most babies who have polydactyly do not have other health problems. But sometimes, it happens as part of a more complex genetic condition or syndrome. These children will have other signs and symptoms and would be best seen by a pediatrician or developmental pediatrician.
How is polydactyly of the foot diagnosed?
Polydactyly of the foot may be seen on a prenatal ultrasound. Otherwise, the health-care team will diagnose it when the baby is born based on a physical examination. After the baby is born X-rays may be done to see the underlying bone structure of the foot or delayed until a later age that is appropriate for an examination. This will show how the extra toe or toes are attached to the foot. This will help the health-care team recommend a course of treatment.
How is polydactyly of the foot treated?
Your child should wear shoes that accommodate their extra toes. Their shoes should fit the foots width, length and height.
Treatment for polydactyly of the foot depends on:
- how the extra toe or toes are attached to the foot
- how foot function is affected
- how developed the foot and toes are at the time of first assessment
Observation
For cases of postaxial (extra toe next to the little toe) or central polydactyly (extra toe in between other toes), the health-care provider may choose to wait and observe as the child grows. This can be done if the extra toe is properly aligned and if normal shoe wear is possible because the foot is not widened so much by the extra toe.
Fully formed toes that attach by bone, blood vessels and soft tissues are more complicated to remove. Treatment is typically observation in these cases. Surgical treatment is considered if there are painful, misaligned toes that prevent normal shoe wearing.
Non-operative treatment
- Accommodative footwear: choosing wider width or height of shoes to fit the extra toes as the foot grows
- Remove extra toes in clinic: If the extra toes are small and unformed, contain no bone and are attached by skin and soft tissues, then a procedure can be done in the clinic to remove them. A vascular clip can be placed at the base of the toe during an outpatient clinic visit. The clip stops blood flow to the extra toe. The extra toe will eventually fall off, like the stump of the belly button does soon after birth. After attaching the vascular clip, the health-care provider puts a bandage on the child’s foot. In a couple of weeks, the child will return to the clinic to have the bandage removed.
Operative treatment to remove extra toes
If your child's extra toes are fully formed, painful or misaligned and they are having difficulty wearing shoes comfortably, then surgery may be recommended to remove the extra toes. Surgery is not usually done until symptoms start to become a problem. Your child may have a problem with footwear, rubbing, bruising, callouses, or catching the toe(s). Surgery to remove extra toes is not done until the foot and toes are large enough to operate on, typically when the child is at least 1 to 2 years old.
A surgical plan will be created based on your child's anatomy, clinical exam and X-rays. The toe(s) will be removed, and the foot reconstructed to improve function, reduce pain and correct alignment of the toes. Surgery will result in some scarring on the foot and will not make the toes or foot appear completely normal.
After surgery, your child may need to wear a cast or splint on their foot while it heals. Your child will have follow-up clinic visits to make sure they are healing well, to check their range of motion and to remove any pins or casts.
Most children do not need post-operative rehabilitation (physiotherapy) for their toes and they return to walking, running and playing on their own without therapy. If the surgery is more extensive, your health-care provider will let you know if your child needs physical and/or occupational therapy to help improve the mobility or function of the toes and foot.
How can you help your child with polydactyly?
You can help your child by:
- making sure they wear accommodative footwear that fits the foot width, length and height
- supporting positive body image
- after surgery, maintaining a dry cast and managing pain as directed by your treating health-care provider
At SickKids
Referrals for polydactyly of the toes at SickKids require photographs of the toes from the top, bottom and sides. Some referrals maybe redirected to a partner surgeon in another hospital.
The first assessment (if referred from time of birth) is typically between 6 to 12 months of age or later. Assessment will include a history, clinical exam and X-rays, counselling and education, and a discussion of early options and management.
Parents are encouraged to continue to monitor motor milestones with their child's primary care provider and continue with their regularly scheduled well-baby visits.
References
Mosca, V. (2014). Principles and Management of Pediatric Foot and Ankle Deformities and Malformations (1st ed.). Wolters Kluwer Health
Zlotolow, D.A. (2023, March 7). Polydactyly. Hospital for Special Surgery. https://www.hss.edu/health-library/conditions-and-treatments/polydactyly
Sheth, U. (2021, June 15). Polydactyly of Foot. Orthobullets. https://www.orthobullets.com/pediatrics/4078/polydactyly-of-foot