The influence of radial displacement in distal radius fracture on the stability of distal radioulnar joint

Abstract

Objective To investigate the causes of instability of distal radioulnar joint caused by displacement in distal radius fracture, and to analyze the importance of radial displacement in distal radius fracture to wrist stability. Methods There were 60 patients with distal radius fracture, 22 males and 38 females, aged from 26 to 67 years, with an average age of 41 years. There were 29 cases with ulnar styloid process fracture and 31 cases without ulnar styloid process fracture. According to the degree of displacement, they were divided into three groups: 13 cases with displacement less than 2 mm, 20 cases with displacement more than 2 mm and less than 4 mm, and 27 cases with displacement more than 4 mm. All the patients were treated with open reduction and plate internal fixation of distal radius fracture. The stability of distal radioulnar joint was examined after plate fixation. Fifteen patients with unstable distal radioulnar joint examined by intraoperative physical examination (associated with ulnar styloid process fracture) were divided into two groups. In one group, the styloid process of ulna was fixed with steel wire, while in the other group the styloid process of ulna was not fixed. The effect of radial displacement on ulnar styloid process after distal radius fracture and the effect of ulnar styloid process fracture on the stability of distal radioulnar joint were analyzed. The degree of radial displacement of distal radius fracture and the effect of ulnar styloid process fracture on the stability of distal radioulnar joint were evaluated according to the postoperative follow-up of palmar inclination angle, ulnar deviation angle and wrist function score. Results The injury of TFCC when radial displacement of distal radius fracture was greater than 4 mm was the main cause of instability of distal radioulnar joint and affecting wrist function. There was statistically significant difference in the incidence of distal radioulnar joint instability whether distal radial fractures accompanied by ulnar styloid process fractures or not. There was significant difference between radial displacement greater than 4 mm and ulnar styloid process fracture. Conclusion The radial displacement of distal radius fracture has great influence on the stability of distal radioulnar joint. There are more patients with ulnar styloid process fracture in the instability of distal radioulnar joint. The ulnar styloid process fracture suggests a higher risk of TFCC injury. The good reduction of ulnar styloid process plays an important role in the stability of distal radioulnar joint. Key words: Radius; Fractures,bone; Distal radioulnar joint; Triangular fibrocartilage complex; Ulnar styloid process