Paediatric forearm and distal radius fractures: risk factors and re-displacement--role of casting indices

Forearm fractures represent one of the most common fractures in children aside from clavicle fractures, and the distal radius is the most common fracture site accounting for 20-30% of these fractures. Maintaining acceptable reduction is not always possible, and re-displacement or re-angulation is the most commonly reported complication. Factors leading to this complication can be broadly divided into three groups: fracture-, surgeon- and patient-related. The quality of casting has been historically measured subjectively. The description of several casting indices by different authors has been a major undertaking, attempting to address objective assessment of this factor. The following have been described: cast index, padding index, gap index, three point index and second metacarpal-radius angle. For distal radius fractures we think that the three point index is the most valuable measurement for predicting re-displacement among surgeon related factors; this index has not been used in forearm fractures in which the rest of the indices seem to be useful in predicting re-displacement. The casting indices should not be interpreted as a separate issue but in conjunction with fracture characteristics and patient factors.