Evaluation for fracture patterns around the wrist on three-dimensional extremity computed tomography, especially focused on the triquetrum

Introduction To describe fracture patterns of triquetrum and analyse them according to fracture classifications, anatomy of intrinsic carpal ligaments and comparison with other wrist fractures. Methods We retrospectively reviewed 297 three-dimensional extremity computed tomographies (CTs) on wrist fractures from October 2007 to January 2012. We initially classified the fractures according to the involved bones and analyzed them according to the patterns of triquetrum fractures, associated carpal bone fractures and presence of combined distal radius fractures. We also correlated the fracture patterns with the patient's injury patterns. Results A total of 297 CTs and 291 patients were included (162 males and 129 females; mean age, 47.8 years). There were a total of 131 carpal bone fractures in 102 patients of 102 CTs. Triquetrum fractures were the most commonly observed cases (36 cases/27.5%). For the triquetrum fractures, the following types were observed: 26 dorsal, five volar, two comminuted fractures are observed in triquetrum. Three other triquetrum fractures show combined forms of other carpal bone fractures. For the combined distal radius fractures, 10 dorsal and two volar fractures were shown. Out of 187 distal radius fractures, 20 showed carpal bone fractures (10.7%). There were no differences in injury patterns according to the fracture patterns. The most common pattern of injury was falling on the outstretched hand, followed by fall from height. Conclusion The dorsum of triquetrum is more frequently fractured than the volar aspect. The number of carpal bone fractures among the patients who have distal radius fractures is higher than usual expectation.