As one becomes more proficient at musculoskeletal ultrasound, the temptation is to assume that one can diagnose all lesions with this modality. The reality is that plain radiographs are an essential part of any ultrasound examination. Xrays are helpful in all age groups.
Examples demonstrating the usefulness of xrays in tandem with an ultrasound study will be given.
Lesions totally within bone will not be seen sonographically but are usually visible on xrays. As these lesions progress, subtle surface changes may be noted but are often not appreciated. Fractures may not be visible, especially if they are in regions not usually studied sonographically. Subtle avulsion fractures are also easily missed sonographically. In addition, some of these fractures are pathognomonic of more serious soft tissue damage which ultrasound cannot demonstrate e.g. the Segond fracture of the lateral tibial plateau indicating an anterior cruciate ligament tear.
Echogenic lesions on ultrasound can be artefactual, due to calcification, torn tendon ends and air. A plain radiograph will eliminate or confirm air and calcification.
Articular lesions may be the cause of a patient's symptoms but the ultrasound scan may only show subtle signs or no evidence at all of this.
Following surgery there may be bone resection, insertion of screws and other fixation devices, arthrodeses and bone troughs among others. Without the information from plain films, the ultrasound scan may be useless.
Dynamic and functional xrays add much needed information and increase the diagnostic yield from sonographic studies.