DRUJ instability after distal radius fracture: a comparison between cases with and without ulnar styloid fracture.

BACKGROUND: Because of the importance of the DRUJ in upper extremity function and the prevalence of distal radius fractures, either with or without ulnar styloid fracture, this study was designed to assess the relationship between ulnar styloid fracture and the incidence of DRUJ instability after treatment of distal radius fractures treated with ORIF (volar plate).

METHODS: 112 patients suffering from type two and three distal radius fractures (Fernandez classification), were evaluated. Depending on the presence of ulnar styloid avulsion fracture, patients were divided into two groups: 86 cases with isolated radial fracture and 26 cases with a distal radius fracture accompanied by ulnar styloid fracture. All patients underwent distal radius fracture ORIF. CT scanning was done both immediately after surgery and 3 months post-op. DRUJ stability was examined using the modified radioulnar line method and the incidence of DRUJ instability was compared between the two groups.

RESULTS: Immediate instability was seen in 11 patients. Three of these patients had concomitant ulnar styloid fracture and were excluded for further fixation. Three months later, another 9 cases were diagnosed with DRUJ instability, 2 of whom had concomitant ulnar styloid fracture and the other 7 suffered from isolated distal radius fracture. Chi-square test revealed no significant difference (p < 0.05). There were no cases of delayed union or non-union distal radius fracture.

CONCLUSION: Our study demonstrated that untreated stable or minimally displaced ulnar styloid fracture accompanied by distal radius fracture, has no adverse effect on DRUJ stability following ORIF of the radius.