Assessment of instability factors in adult distal radius fractures.

Background: The purpose of this study was to evaluate the radiographic outcome of unstable distal radius fractures treated by closed reduction and sugar tong splinting and to quantitatively evaluate Lafontaines' criteria of instability.

Methods: Fifty patients with 3 or more instability factors as described by Lafontaine were treated by finger trap traction, closed reduction, and sugar-tong splinting. They were evaluated radiographically for initial angulation, radial inclination, radial length, and palmar tilt at the time of injury, after reduction, and 1 week, 2 weeks, and 4 weeks after reduction. The fracture either maintained an adequate reduction or failed to maintain an adequate reduction and showed secondary displacement based on specific criteria.

Results: At 4 weeks after reduction 46% of these unstable distal radius fractures maintained an adequate reduction. Of the 54% of fractures that failed to maintain an adequate reduction, age was the only statistically significant predictor of secondary displacement. After obtaining an acceptable initial closed reduction, patients 58 years of age were found to be at 50% risk for secondary displacement. The risk for displacement with an unacceptable radiographic result was found to increase with increasing age and decrease with decreasing age.

Conclusion: In the closed management of these potentially unstable distal radius fractures, age was the only statistically significant risk factor in predicting secondary displacement and instability. These data help guide treatment by closed reduction and immobilization with serial x-rays or by surgical stabilization.