ROLE OF PLASTER MOULDING IN REDISPLACEMENT OF PAEDIATRIC FOREARM FRACTURES

Abstract

We assessed two simple radiological methods of predicting redisplacement of forearm fractures in children: a) Cast Index (ratio of sagittal to coronal cast width at the fracture site), and b) Padding Index (ratio of padding thickness at the fracture site in the plane of the deformity to the maximum interosseous width).

Case records and radiographs of 100 children who underwent a manipulation under general anaesthesia for a displaced fracture of forearm or wrist were studied. Redisplacement was defined as more than 15 degrees of angulation and/or more than 50 percent of translational displacement on check radiographs at 1–2 weeks.

Angulation (in degrees) and translation displacement (in percentage) were measured on the initial and check radiographs. Cast index and Padding index were measured on the check radiographs. Good intra and inter observer reproducibility was observed for both these measurements. The cast index was validated in an experimental study.

Redisplacement was seen in 29 cases. Of these 21 cases underwent a secondary procedure for redisplacement. Initial displacement, cast index and padding index were the three factors which were significantly higher in the redisplacement group (p< 0.05). The means and 95% Confidence intervals for cast index and padding index were 0.88 (0.84, 0.90) and 0.48 (0.39, 0.62) in the redisplacement group whereas were 0.71 (0.69, 0.72) and 0.11 (0.09, 0.12) in the group with no redis-placement respectively. No statistically significant difference was seen for age, fracture location, initial angular deformity and seniority of the surgeon.

Conclusion: cast index and padding index are simple and reliable radiographic measurements to predict the redisplacement of forearm fractures in children. A plaster with a cast index of> 0.9 and padding index of > 0.3 is prone to redisplacement.