The purpose of this study was to make an assessment of distal radioulnar joint (DRUJ) instability after the treatment of intra-articular fractures of the distal radius using computed tomography (CT) including contralateral normal wrist.

Twenty-seven intra-articular fractures of the distal radius in twenty-seven patients who had had the surgical treatment were evaluated at follow-up of mean 17.9 months (range, 10-36 months). The DRUJ was assessed with clinical examination, plain radiography, and bilateral CT. CT scans were obtained in 70° pronation, neutral, and 70° supination. The radioulnar ratio and the subluxation ratio which was modified radioulnar line method were used to measure DRUJ instability.

Eight patients were diagnosed as DRUJ instability based on CT assessment. Nine patients were considered to have DRUJ instability in clinical examination, but 4 patients of them were confirmed to have DRUJ instability based on CT measurements. Nonunions of ulnar styloid or malunions of the distal radius were not found to have statistical correlation with DRUJ instability (p>0.05).

In patient with suspicious DRUJ instability following distal radius fractures, we recommend computed tomography scans of both the injured and uninjured wrists in pronation, neutral, and supination position for objective assessment.