Congenital and Pediatric Hand Conditions
Core concepts
Congenital anomalies are organized by embryologic failure: failure of formation (radial longitudinal deficiency, cleft hand), failure of separation (syndactyly), duplication (polydactyly), overgrowth (macrodactyly), and constriction band sequence. Timing drives treatment. Syndactyly release is generally performed at 6-12 months, earlier for border digits or complex bony syndactyly that risks tethering and angular deformity. Polydactyly reconstruction should preserve a stable, well-aligned digit rather than simply excising the extra ray.
Radial longitudinal deficiency requires systemic workup for VACTERL and Fanconi anemia; chromosome breakage testing should precede elective surgery. Treatment is staged, often beginning with soft-tissue distraction before centralization or radialization. Pediatric trigger thumb usually presents with a Notta nodule and resolves within the first year, so observation precedes release. Thumb-in-palm and clasped thumb are distinct entities. Physeal injuries follow Salter-Harris classification; the physis is the weak link, so a "sprain" that does not improve warrants imaging.
Traps
Operating on a newborn trigger thumb, excising a duplicate without reconstructing collateral ligaments, missing Fanconi anemia before elective surgery, and confusing camptodactyly with trigger finger are classic question traps. Also remember that a child's joint may reduce seemingly well while a physeal fracture is present.
Rule of thumb
For simple complete syndactyly, plan release at 6-12 months and never operate on both sides of the same digit at one setting, to protect the digital vessels.