Fractures of the triquetrum in children.

Fractures of the triquetrum are a more common cause of posttraumatic wrist pain in children than is usually appreciated. These fractures are often very subtle "flake" avulsion or impingement fractures requiring good oblique radiographs for recognition. The incidence is probably much higher because many fractures go undiagnosed as a wrist "sprain" or type I epiphyseal injury of the distal radius and ulna. An outcome study of carpal injuries at the Children's Hospital of Eastern Ontario, a regional pediatric trauma center, disclosed 15 children who had sustained a triquetral fracture. Three were initially missed, and most were flake fractures. An average follow-up of 4 years showed only two patients with complaints of wrist stiffness and discomfort with hyperextension of the wrist. The increased ligamentous laxity of the wrist in children may actually predispose to triquetral injury by causing ulnar impingement of the triquetrum with ulnar deviation and extension of the wrist. Pain in a child's wrist just distal to the ulna, the "triquetral point," should arouse suspicion of a fracture of the triquetrum.