Children With Synpolydactyly Type I Homozygous HOXD13 Mutations: Embryology and Surgical Correction of the "Cupping" of the Hands and Feet.
Samir O Alsayegh, Abdullah M Alghamdi, Mohammad M Al-Qattan
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Case in brief
Three children with familial Synpolydactyly Type I and severe flexion deformities at the metacarpophalangeal or metatarsophalangeal joints had cupping of the hands or feet. Two had postaxial toe deformities that caused them to step on the dorsal surfaces of the affected toes; they underwent dorsal wedge osteotomies of the metatarsals. The third had hand deformity treated with syndactyly release and release of tight volar skin and metacarpophalangeal volar plates. Surgery partially corrected the deformities. At follow-up beyond 5 years, the children walked on the plantar surfaces of their toes or used the hand well in daily activities, and parents were satisfied.
What made this case unusual
The report describes severe cupping in children with familial Synpolydactyly Type I that impaired function and required surgical correction, including toe deformity severe enough to make the children step on the dorsal surfaces of the affected rays.
Diagnostic / clinical pearl
In familial Synpolydactyly Type I, marked flexion deformity at the metacarpophalangeal or metatarsophalangeal joints can produce functionally significant cupping; assess how the deformity affects hand use and weight-bearing.
Why it matters
Although correction was partial, the reported procedures were followed by useful hand function or plantar weight-bearing in these children, illustrating that functional improvement may accompany incomplete anatomical correction.