Clinical and Radiographic Factors Associated With Distal Radioulnar Joint Instability in Distal Radius Fractures

Background Distal radioulnar joint (DRUJ) instability is an important cause of ulnar-sided wrist pain in distal radius fractures. However, instability is frequently undiagnosed and the clinical and radiographic factors associated with instability are not well understood. Questions/purposes We therefore identified clinical and radiographic factors associated with DRUJ instability in distal radius fractures. Patients and Methods We retrospectively reviewed all 221 patients who underwent surgical treatment for unstable distal radius fractures from 2007 to 2010. Ten patients (five men and five women) had DRUJ instability by intraoperative manual testing (Group I); these patients had a median age of 52 years. The other 211 patients (81 men and 130 women) (Group II) had a median age of 55 years. Clinical and radiographic data were compared between the groups. Results The incidence of open wounds at the wrist and the relative ulnar length measured on the prereduction radiograph were greater in Group I. An open wound at the wrist and positive ulnar variance of 6 mm or greater on the prereduction radiograph increased the risk of DRUJ instability (relative risks = 45 and 17, respectively) in distal radius fractures. Conclusions An open wound at the wrist or positive ulnar variance of 6 mm or greater observed on the prereduction radiograph in patients with distal radius fractures should alert the physician to the possibility of DRUJ instability. Level of Evidence Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.