The condition of having toes that are fused or “stuck together” is medically termed syndactyly. This common congenital difference is present from birth, occurring in approximately 1 in every 2,000 to 3,000 newborns. While many people with syndactyly live without functional limitations, the condition results from a failure in a specific developmental process. Syndactyly is most frequently seen between the second and third toes, where a band of skin or deeper tissue connects the adjacent digits.
Defining and Classifying Webbed Toes
Syndactyly is the fusion of two or more adjacent digits, which can involve the hands or the feet. The condition is categorized based on the tissues involved and the extent of the fusion. Simple syndactyly occurs when the digits are joined only by skin and soft tissue. If the fusion involves bone, cartilage, or nails, it is referred to as complex syndactyly.
The length of the fusion determines if it is complete (extending to the tips of the toes) or incomplete (a partial connection). Complete simple syndactyly, involving only soft tissue fusion along the entire length of the toes, is the most common presentation.
Genetic and Developmental Causes
Syndactyly results from a disruption of normal limb development during the sixth to eighth week of embryonic growth. Initially, the hands and feet form as paddle shapes with connected digits. Programmed cell death, known as apoptosis, normally removes this connecting tissue to create five separate digits. Syndactyly occurs when this apoptotic process fails or is incomplete, preventing full separation.
In many cases, syndactyly appears as an isolated finding, known as non-syndromic syndactyly. This isolated form frequently follows an autosomal dominant inheritance pattern, meaning a child has a 50% chance of inheriting the trait if one parent is affected.
When Webbed Toes Signal a Larger Issue
While many cases of fused toes are isolated, the condition can sometimes signal a broader genetic syndrome affecting multiple body systems. Syndromic syndactyly occurs when fused toes are one of several symptoms associated with a complex disorder. Over 300 different syndromes have been linked to the presence of fused digits.
Examples include Apert syndrome, characterized by skull and face abnormalities alongside severe complex syndactyly of the hands and feet. Poland syndrome may involve missing or underdeveloped muscles on one side of the body, along with hand and foot differences. A medical evaluation is necessary if fused toes are accompanied by other physical differences, suggesting a systemic condition.
Surgical Correction and Management
Treatment decisions are based on functional impairment or cosmetic concerns. For simple syndactyly of the toes that does not affect walking or shoe-wearing, non-operative management is common. Surgical separation is often considered to create a new web space, especially when the fusion involves unequal-length digits, which can lead to progressive angulation or growth restriction.
The procedure involves separating the fused digits and reconstructing the web space. Ensuring adequate skin coverage is necessary to prevent the digits from fusing again, a complication known as “web creep.” This typically requires local skin flaps, often combined with full-thickness skin grafts taken from a different site on the body to cover the raw surfaces. Surgery is often timed for early childhood, with many surgeons preferring to wait until the child is around 18 months of age for simple cases.