Evaluation of the Foveal Involvement of the Ulnar Styloid Fracture: A Comparison of the Plain Radiography and Three-Dimensional Computed Tomography

ABSTRACT

PURPOSE: There remains uncertain whether to fix or not an ulnar styloid fracture acommpanied by distal radius fracture. Fixation might be required in cases of the fracture involving a fovea of ulnar head, an attachment site of deep triangular fibrocartilage, which is thought to be important to distal radioulnar joint stability. We analyzed a fovea involvement of an accompanied ulnar styloid fracture in patients with distal radius fracture by simple radiograph and three-dimensional computed tomography (3D CT). METHODS: We retrospectively reviewed 168 patients who underwent surgery with volar locking plate for distal radius fracture in our hospital from January 2005 to March 2015 and evaluated a fovea involvement of ulnar head by simple radiographs and 3D CT respectively, and compared. RESULTS: On simple X-ray, 64 cases (38%) were ulnar styloid fovea fractures; however, 21 cases of these revealed non-fovea fractures by 3D CT. And 7 out of 104 cases determined as non-fovea fracture by simple radiographs were diagnosed as fovea fractures by 3D CT. Sensitivity, specificity and accuracy of evaluation by simple radiograph were 86%, 82% and 83% respectively, when compared with those of 3D CT based evaluation. CONCLUSION: Accuracy of evaluating an accompanied ulnar styloid fovea fracture in patients with distal radius fracture by simple radiograph, when compared with 3D CT, was 83%; therefore, we recommend using the 3D CT based evaluation instead of simple radiograph based one for determination of fovea involvement of ulnar head.