Effect of an ulnar styloid Base unrepaired fracture on outcome after plate fixing of a distal radus fracture

Abstract

Background: The impact of an unrepaired ulnar styloid base fracture on recovery after internal fixation of a distal part of the radius fracture is uncertain. To test the hypothesis that there is no difference in wrist motion or function scores between those with an untreated fracture of the ulnar styloid base and those without ulnar fracture, we assessed a series of patients with an internally fixed fracture of the distal part of the radius. Methods: In a prospective study of plate-and-screw fixation of distal radial fractures, two cohorts of seventy-six matched patients, one with a fracture of the ulnar styloid base and the other without ulnar fracture, were retrospectively analysed. They matched patients for age, sex, type of AO fracture, and mechanism of injury. The two cohorts were analyzed at six, twelve and twenty-four months postoperatively for differences in motion, grip strength, pain, the Gartland and Werley score, arm, shoulder, and hand score disabilities, and the Short Form-36 score. Sixty-four patients with < 2mmof displacement of a ulnar styloid base fracture were compared with forty-nine patients with greater displacement in a second analysis. With the use of regression analysis and the probability ratio test, differences between cohorts and cohorts were determined over time. Results: No significant differences were found at any of the follow-intervals between patients with an unrepaired fracture of the base of the ulnar styloid and those without ulnar fracture. However, at six months, there was a trend towards lower grip strength (71 percent [on the contralateral side] compared to 79 percent; mean difference, 28 percent [95 percent confidence interval= 215.3 percent to 20.6 percent]; p= 0.03) and lower bending (54 compared to 59; mean difference, 25[95 percent confidence interval= 211.7 to 20.8]; p= 0.02) and ulnar deviation (32 compared with 59). There were no significant differences in any measurement of the tested outcome between patients with a displacement of an unrepaired fracture of the ulnar styloid base and patients with less displacement. Conclusions: After treatment of a distal radial fracture with plate-and-screw fixation, an unrepaired fracture of the base of the ulnar styloid does not appear to influence function or outcome, even when the ulnar fracture was initially displaced ≥2mm.

Keywords: ulnar styloid, distal radial, fracture, plate fixing, unrepaired fracture.