Congenital Symptomatic Scaphoid-Trapezium Coalition in a Pediatric Patient With VACTERL Association.

Carpal coalition is the union between two or more carpals that should otherwise have uninterrupted mobility. Of those reported among pediatric populations, the vast majority are lunotriquetral (69.2%) or capitohamate (17.3%), while scaphotrapezial (ST) is among the most rare. Here, we report a case of a pediatric patient with symptomatic congenital ST coalition as part of the VACTERL association that resolved with surgical intervention. A 9-year-old right-hand-dominant girl with consistent right wrist and snuffbox pain following an incidental fall-on-outstretched hand was later revealed to be symptomatic of congenital ST coalition and unrecognized Blauth grade 1 thumb hypoplasia. Her medical history was notable for a ventricular-septal defect and tracheoesophageal fistula, suggesting a possible VACTERL association. Initial radiographs revealed no acute fractures, but demonstrated developmentally abnormal carpus. The patient experienced continued pain in the radial aspect of her right wrist and first carpometacarpal joint for 5 months despite immobilization and conservative treatment. Physical examination revealed carpometacarpal joint tenderness, unrecognized thumb hypoplasia with underdeveloped thenar musculature, weakened thumb grip, and reduced oppositional movement. Magnetic resonance imaging confirmed hypoplastic thumb and ST coalition, with genetic testing consistent VACTERL association. Surgical management included a right ST-coalition resection, partial carpectomy of the proximal trapezium and distal scaphoid, and fat grafting to the ST interval. The procedure was successful, with no postoperative complications. The patient reported considerably decreased pain with activities that previously elicited pain such as writing and sports. Carpal coalition is a rare congenital abnormality, typically asymptomatic and found incidentally on radiographs. Most cases are often resolved conservatively, though surgery may be indicated for those with continued pain and impairment. For pediatric patients who may have other association/syndrome indications (e.g., VACTERL and Holt-Oram) and otherwise continual wrist pain failing to respond to conservative therapy, carpal coalition may be a contributing factor to their symptoms.