[Ultrasound imaging of osteosynthesis materials in traumatology--an experimental study]

The aim of the present study was to establish the typical ultrasound (US) patterns of metal implants used for internal fracture fixation, and consequently to use US for the identification and localisation of such implants. We investigated both the visualization of the implants in term of size and shape, material (titanium, steel, biodegradable screws) and surface structures, and possible changes in the echo pattern in relationship to surrounding structures (muscles, body fluid), proximity to bone, and changes in the angle of insonation. For this purpose ultrasonography was performed on artificial and isolated cadaver bones in a water bath, as well as on cadaver limbs following prior implantation of screws, plates, K-wires and cerclage wires. We found that, from a certain size upwards, metal implants can be easily localised on the basis of typical artefacts (resonance artefact, comet-tail artefact). US is thus most suitable for localisation of metal implants. The spatial and anatomical relationship to bony structures, joints, tendons, muscles and blood vessels can be determined with a high degree of accuracy.