Trauma of the wrist.

In wrist injury, plain radiographs form the basis of diagnostic imaging, and can provide definitive answers in most cases. MR imaging is the method of choice for several diagnostic problem cases. These problems can include radiographically occult fractures where MRI enables early diagnosis compared to follow-up radiographs. Early stage diagnosis of a post-traumatic avascular osteonecrosis with high sensitivity and specificity, is only possible with MRI. In these instances, radiographs are only sensitive in later stages and scintigraphy is quite nonspecific. Stress fractures, invisible with other modalities, are also demonstrable with MRI. In addition, MRI is helpful in special circumstances with regard to non-union or pseudarthrosis. In wrist instability, radiographs in combination with stress views and fluoroscopy are still the initial diagnostic step. MRI, with the advantage of direct visualization of the wrist ligaments and triangular fibrocartilage complex, offers very promising results in this area. Generally, for the evaluation of wrist injury, MRI can be considered the most important second-step procedure in patients where radiographs are nondiagnostic.