Rationale and objectives: Carpal Box (CB) radiographs, transverse and longitudinal, produce elongated and magnified views of the carpus. These radiographs can be used after carpal injury, in addition to conventional scaphoid x-rays. In this study, the use of CB radiographs was evaluated in patients with possible scaphoid fracture.
Methods: Seventy-one consecutive patients who presented at the First Aid department from May 1994 to May 1995 were included. All patients were examined for scaphoid fracture after a fall on the out-stretched hand. If a scaphoid fracture was seen on the scaphoid x-rays, patients were immobilized. If the x-rays remained negative or dubious for fracture, additional transverse and longitudinal CB radiographs were obtained. If CB radiographs remained negative or inconclusive, patients were referred for three-phase bone scintigraphy. The results of independent and masked judgment by three different observers were used for an inter- and intraobserver analysis.
Results: Twenty of 71 patients initially showed a scaphoid fracture on the conventional scaphoid x-rays, 41 were negative, and 10 inconclusive. All 41 negative patients remained negative on CB radiograph; however, the bone scintigraphy was positive for scaphoid fracture in 11 patients and in 9 patients a hot spot elsewhere in the carpus was found. Of the 10 patients with inconclusive x-rays, 2 showed a clear fracture of the scaphoid on CB radiograph, 5 were negative, and 3 remained inconclusive. The agreement between observers, calculated in kappa values, was highest in CB radiographs.
Conclusions: In the diagnosis of scaphoid fracture, Carpal Box radiography is of limited value in patients with clinically suspected scaphoid fracture. In two of 10 patients with initial dubious scaphoid x-ray, bone scintigraphy can be avoided. Furthermore, the reliability of the interpretation of the radiographs is increased by additional Carpal Box radiography.