Carpal Box radiography in suspected scaphoid fracture

We have assessed the value of using a simple apparatus,the Carpal Box, in patients with suspected scaphoid fracture, to produce elongated and magnified radiographs of the carpus. The interobserver agreement between 60 observers of standard scaphoid radiographs and longitudinal and transverse Carpal Box radiographs (X-CB) was compared in 11 patients. Three-phase bone scanning was used as a comparative standard. If at least 75% of the observers agreed and the result was confirmed by three-phase bone scanning, the outcome was termed reliable. Scaphoid radiographs and the longitudinal X-CB films were reliable in four patients and the transverse X-CB films in six patients. The bone scan suggested a scaphoid fracture in five of the 11 patients. Agreement in the interpretation of the standard scaphoid radiographs was acceptable in only 36% of patients: in interpretation of transverse Carpal Box radiographs this figure increased to 55%.