Triple-injection wrist arthrography: unidirectional communications are due to technical factors.

One justification for triple-injection wrist arthrography is detection of unidirectional interjoint communication that might escape notice if only a single joint were injected. To determine whether the direction of 1-way communications is related to the choice of the first joint injected, the authors prospectively randomized 100 wrists undergoing consecutive single-contrast, fluoroscopically controlled arthrograms into 2 well-matched groups. One group received the initial injections into the midcarpal and distal radioulnar joints and the other group received the initial injection into the radiocarpal joint. Two unidirectional radial capsular communications with the radiocarpal joint were detected on delayed midcarpal joint injection. No other unidirectional communications were found. No statistically significant difference was found between the midcarpal and radiocarpal study groups. Thus, the first joint injected appears to be a major determinant in demonstrating unidirectional communications between wrist compartments.