Anatomical landmarks in the paediatric distal radius: a new method for measuring epiphyseal height

Abstract

Elastic stable intramedullary nailing for fixation of paediatric forearm fractures has become the preferred method of osteosynthesis. The aim of the study was to develop a method for finding the correct entry point in the distal radius of children of all ages as a distance from the radial styloid, a landmark which is readily palpable at the wrist. MRI scans of the wrist in 19 children aged 2-7years (mean 5) were reviewed. We noted that the proximal edges of the ossific nucleus of capitate and the tip of the radial styloid were at the same vertical height from the physis. This allowed us to review 519 wrist radiographs of children aged 2-14years (mean 7.98) to measure the epiphyseal height, as the radial styloid does not ossify until the age of 14years. The epiphyseal height had a mean of 16.67mm (13-21mm). The epiphyseal height in boys was greater than the girls by a mean of 1.2mm (p<0.0005). For the absolute safe distance, we recommend an insertion site 40mm proximal to the tip of the radial styloid, which is safe in all children with an open distal radial physis. This simple and reproducible method allows the identification of the insertion site for the nail with only the minimal use of imaging.