Can radiological parameters predict failure of fixation in distal radius fractures treated with a volar locking plate?

INTRODUCTION: Fractures of the distal radius are common, and volar locking plates are the most utilized fixation method. Failure of fixation, defined as post-operative fracture collapse leading to loss of reduction and/or screw penetration, is an undesirable outcome. We aimed to demonstrate whether preoperative and intraoperative radiographic parameters are associated with subsequent failure of fixation in order to produce a model that may be able to predict failure.

METHODS: A retrospective case-control study of 23 cases of failure of fixation matched to controls from the same cohort by age, sex, and AO classification in a 3:1 ratio. Nine initial injury and 13 intraoperative radiological parameters were evaluated, and multi-variate regression analysis models were analysed to assess if they could reliably predict failure.

RESULTS: A total of 92 patients were analysed (23 cases, 69 controls). Size of intraarticular gap was the only preoperative parameter to be associated failure with every 0.47 mm increase in fracture gap resulting in a 1.6 increase of odds ratio of failure. Based on intraoperative radiological parameters, three factors were associated with failure: dorsal capitate translation, intraarticular gap and step. Models based on these parameters do not accurately predict failure, however, models based on intraoperative factors are associated with risk of failure with high specificity but low sensitivity.

CONCLUSION: We conclude that the severity of the injury is less importantly associated with failure of fixation, whereas the quality of the surgical fixation and specifically the accuracy of the reduction are more important.