Union of the ulnar styloid fracture as a function of fracture morphology on conventional radiographs

Abstract

In a retrospective radiological study, the authors aimed to detect the influence of fracture morphology on the union rate of ulnar styloid fractures associated with distal radial fractures. Eighty-two out of 101 ulnar styloid fractures were included in the final statistical analysis. Initially, they were grouped into six different morphological types based on a novel classification system. They were also classified as per the established Fernández and Frykman classification systems. Furthermore, the initial ulnar styloid displacement was measured in conventional anteroposterior radiographs. Union of the ulnar styloid fracture was evaluated after at least 6months of follow-up. The current investigators demonstrated that the various ulnar styloid fracture patterns have no significant predictive value for ulnar styloid union. In contrast, it could be attested, that an initial fragment dislocation of greater than 2.4mm in the conventional AP radiographs has a significantly lower chance of successful union (p = 0.022). Initial displacement of the ulnar styloid should be measured in each distal radial fracture with a concomitant ulnar styloid fracture. This could be useful to inform the decision regarding surgical fixation of the ulnar styloid fragment in patients with an unstable distal radioulnar joint (DRUJ) or persistent symptoms at the ulnar aspect of the wrist.