Displaced distal radius styloid fracture.

AAOS Now

Published 1/1/2010
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Peter Pollack

Styloid fractures may not affect outcomes of distal radial fractures

Income more significant in patient-rated outcomes

The presence of an ulnar styloid fracture may have little effect on patient-rated outcomes among patients treated with open reduction and internal fixation (OR/IF) for a distal radius fracture, as long as the distal radioulnar joint (DRUJ) is stable, reported Douglas M. Sammer, MD, at the 2009 annual meeting of the American Society for Surgery of the Hand.

Study parameters
Distal radius fractures account for about 1 in 6 fractures seen in the emergency department; ulnar styloid fractures are present in an estimated 50 percent to 65 percent of those cases. Previous studies have found contradictory evidence regarding the effects of ulnar styloid fractures in the setting of distal radius fractures. Although some studies found little effect on outcomes, others found that ulnar styloid fractures can contribute to poor results, such as instability of the DRUJ, ulnar-sided wrist pain, stiffness, and weakness.

The research team drew data prospectively from an ongoing longitudinal study designed to evaluate the outcomes of distal radius fracture treatment. They enrolled 144 consecutive patients who were treated with volar locking plating; patients with DRUJ instability that was treated at the time of distal radius OR/IF were excluded. Only patients with a stable DRUJ were included in the study.

Further exclusion criteria included age younger than 18 years, other concomitant upper extremity injuries, severe multisystem trauma, bilateral distal radius fractures, and fractures treated more than 2 weeks after injury.

Three additional patients were excluded after undergoing OR/IF for both displaced ulnar styloid base fractures and distal radius fractures because of DRUJ instability.

Patients completed the Michigan Hand Outcomes Questionnaire (MHQ) and were examined by the attending surgeon and a physician’s assistant specializing in hand. The first patients enrolled in the study had follow-up at 3 months, 6 months, and 12 months; a 6-week follow-up was added for patients enrolled later in the study because researchers found a rapid level of progress at 3 months.

Follow-ups included specific evaluation of the DRUJ for instability and pain, along with the piano key test on both the injured and uninjured sides. The piano-key test involves depressing the distal ulna from dorsal to volar with the hand pronated. A positive result is characterized by painful laxity in the affected wrist compared with the contralateral wrist.

Overall, the researchers evaluated 40 patients (28 percent) at 6 weeks, 108 patients (75 percent) at 3 months, 91 patients (63 percent) at 6 months, and 59 patients (41 percent) at 12 months. Of the 144 patients included in the final study, 88 (61 percent) had associated ulnar styloid fractures, while 56 (39 percent) did not.

Income level predicts outcome scores
Through the course of the study, 24 patients (32 percent) demonstrated evidence of union, and no patients exhibited instability of the distal radioulnar joint. One patient reported pain, but no instability.

Dr. Sammer reported that the mean MHQ scores improved over time, whether or not the patient had an ulnar styloid fracture. Additionally, the presence of an ulnar styloid fracture was not an independent predictor of MHQ score after adjustment for other covariates (p = 0.55). Among patients who had ulnar styloid fractures, degree of displacement was also not found to be an independent predictor of MHQ score after adjustment. Finally, the healing status of the fracture (union versus nonunion) did not significantly predict MHQ scores (p = 0.95).

One notable predictor of MHQ score, according to Dr. Sammer, was income level. Patients with an annual income of less than $70,000 had a mean MHQ score 9 points lower than patients with annual incomes greater than $70,000 (p = 0.0003). There was no statistically significant difference in the income levels between patients who did or did not have ulnar styloid fractures.

One limitation of the study was the lack of data after 12 months postsurgery. If patients been followed for a longer time, significant changes in MHQ scores might have been noted. Dr. Sammer pointed out, however, that the mean MHQ scores approached the normal range and appeared relatively stable by the 12-month follow-up, suggesting that further significant changes were unlikely.

Dr. Sammer’s co-authors for “The Effect of Ulnar Styloid Fractures on Patient-rated Outcomes after Volar Locking Plating of Distal Radius Fractures” include Hriday Shah, BS; Melissa J. Shauver, MPH; and Kevin C. Chung, MD, MS. The authors report no conflicts of interest.

Peter Pollack is a staff writer for AAOS Now. He can be reached at ppollack@aaos.org