Abstract
Although Bohler’s & Gissane’s angles are measured in adult calcaneal fractures, it is not known if such measurements are reliable in children nor how such measurements vary with the age of the child.
The Picture Archiving and Communications System (PACS) databases of 2 London Teaching Hospitals were searched and all children who had a lateral ankle xray taken as part of their attendance to the A& E department were identified. Films were excluded if there was a fracture of the calcaneus or if the film was oblique or of poor quality. Bohler’s and Gissane’s angles were measured using the image viewer software. All patients’ films were measured on two separate occasions and by two separate authors to allow calculation of inter- and intra-observer variation. Interclass Correlation Coefficients (ICC) were used to assess the reliability of the measurements.
347 children were identified and after exclusions, 218 films were used for the study. The overall ICC for Bohler’s angle inter-obsever error was 0.91 and for intra-observer error was 0.92, giving excellent correlation. This reliability was maintained across the age groups. Gissane’s angle inter-observer error was very poor and the intra-observer error poor across the age groups, although accuracy did improve as the patients approached maturity.
Further analysis of the Bohler’s angle showed a significant variation in the mean angle with age. Contrary to published opinion, the angle is not uniformly lower than that of adults but varies with age, peaking towards the end of the first decade before attaining adult values.
We feel that measurement of Gissane’s angle is unreliable in children but measurement of Bohler’s angle is accurate and reproducible. Bohler’s angle varies with age and knowledge of Bohler’s angle variation is important in the evaluation of os calcis fractures in children.
Correspondence should be addressed to BSCOS c/o BOA, at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE, England.
