Predicting redisplacement after manipulation of paediatric distal radius fractures: the importance of cast moulding

The majority of displaced distal radius fractures are managed by closed reduction and cast immobilisation. Redisplacement is associated with initial displacement, imperfect reduction and quality of cast. The aim of this study was to establish which factors predict the risk of redisplacement.

A retrospective analysis between September 2010 and April 2013 of children who underwent closed manipulation and cast immobilisation for a distal third radius fracture was performed. Open fractures, those treated with fixation, and cases with associated dislocations or physeal injuries were excluded. Initial fracture translation and angulation, the distance from the physis and the presence of an ulna fracture were recorded. Intra-operative radiographs were analysed to assess reduction, the cast index and gap index. Clinic records and post-operative radiographs were reviewed to identify redisplacement or further surgical intervention.

During the study period, 107 children underwent closed reduction and casting: 82 boys (76.6 %) and 25 girls (23.4 %), and the mean age of the group was 10 years. Twenty-nine children (27 %) suffered a radiographic redisplacement although only five children underwent a second surgical intervention. Statistically significant risk factors for redisplacement were initial fracture translation (p < 0.001), success of reduction (p < 0.001) and associated ulna fracture (p = 0.021). Both the mean cast index (0.81 vs. 0.78) and mean gap index (0.16 vs. 0.14) were higher in the redisplaced group, but this did not reach statistical significance.

Closed reduction and immobilisation of paediatric distal radius fractures is associated with a high redisplacement rate. Initial fracture type and success of reduction are key risk factors.