[The imaging of hamate fractures in the conventional X-ray and CT: experimental results and clinical experiences]

Examination of the ability to image fractures of the body and hook of the hamate bone in conventional X-rays and HR-CT.

In an in vitro experiment on 18 cadaver hands, the hamate bone was fractured at different localisations. Before and after fracture, conventional x-rays were taken in different projectional planes: a.-p., lateral, oblique and carpal tunnel view, as well as an HR-CT with 2 mm layer thickness in the axial, sagittal and coronal plane. In addition, 15 clinically verified hamate bone fractures (two body and 13 hook of hamate fractures) were reviewed retrospectively to assess the value of the imaging procedures that led to diagnosis.

Taking into account all conventional x-ray projections applied, the in vitro experiment yielded a sensitivity of 72.2%, a specificity of 88.8% and an accuracy of 80.5%. For CT, the sensitivity was 100%, the specificity 94.4% and the accuracy 97.2%. In retrospective clinical evaluation, 60% of the existing fractures were identified in the conventional x-ray images. The remaining fractures were detected by additional procedures like scintigraphy, conventional tomography and CT.

For the diagnosis of fractures of the body and hook of the hamate HR-CT is the imaging procedure of choice, in which case an axial or sagittal plane should be chosen.