GAP INDEX – A GOOD PREDICTOR OF FAILURE OF PLASTER CAST IN DISTAL FOREARM FRACTURES

Abstract

The aim of this study was to assess the usefulness of Cast index and an indigenously developed Gap index as measures of poor moulding of plaster. 20 cases of re-manipulation of distal third forearm fractures excluding growth plate injuries were compared with a control of 80 patients. 5 patients in the control group had an axial deviation of more than 10 degrees but were not remanipulated and therefore were included in the failure group. The gap index and the cast index of the two groups was compared as predictors of failure of conservative treatment. The groups were similar in terms of demography and post reduction alignment. There was a significant difference (< 0.001) in the Cast index and the Gap index of both the groups. The sensitivity of the Cast index (> 0.8) in predicting failure of plaster was 48% while that of the sum of Gap index (> 0.15) in AP & Lat view was 88%. Gap index was found to be more accurate (84%) than Cast index (78%) in predicting failure. The gap index is a better predictor of failure than the cast index. A quick assessment of these indices, especially by the less experienced surgeons, is a good practice before accepting any plaster following a manipulation of distal radial fractures. It would not only save the patient a second anaesthesia but also complications of a more extensive second procedure and of course hospital resources.