Predicting Alignment After Closed Reduction and Casting of Distal Radius Fractures

PurposeWe sought to independently validate the McQueen equation and LaFontaine's criteria as predictors of instability in a large series of distal radius fractures treated nonsurgically. In addition, we hypothesized that restoring the volar cortical integrity (ie, volar hook) would be another factor that would independently predict the maintenance of a closed reduction in a cast.MethodsWe screened 546 consecutive distal radius fractures with 168 meeting all inclusion criteria. Dorsal tilt, radial height, radial inclination, ulnar variance, and carpal malalignment were measured on initial postreduction and final radiographs. A univariate analysis evaluated the predictability of the McQueen equation, Lafontaine's criteria, and volar hook on each radiographic parameter. A multivariate analysis was performed using the significant results from the univariate analysis.ResultsIn the univariate analysis, the McQueen formula, the number of Lafontaine criteria, and age all correlated with radial height, radial inclination, and ulnar variance. In the multivariate analysis, age correlated with the most radiographic factors including radial height, radial inclination, ulnar variance, and carpal alignment at healing. Volar hook correlated with dorsal tilt and carpal alignment at healing, and dorsal comminution correlated with dorsal tilt.ConclusionsIn the nonsurgical treatment of distal radius fractures, we were able to validate the McQueen equation and Lafontaine's criteria in predicting the final radial height and inclination and final ulnar variance. Neither method was predictive of final dorsal tilt or carpal malalignment. However, restoring volar cortical continuity by hooking the volar cortex in the initial reduction proved to be the strongest predictor of final volar tilt, the change in volar tilt, and carpal malalignment at union.Type of study/level of evidenceTherapeutic III.