THE RELIABILITY OF A NEW COMPUTERIZED TECHNIQUE FOR MEASURING EPIPHYSEAL PLATE ZONAL HEIGHT

Abstract

The objective of this study was to assess the reliability of a new computerized technique for measuring epiphyseal plate zonal height. A fully crossed two factor generalizability experiment in which the effect of observers and time on the reliability of measurements of zonal height within different regions (center and periphery) of the epiphyseal plate was examined. Photomicrographs from both the central and peripheral regions of each of the 30 canine distal ulna epiphyseal plate histological sections were considered; within each region, the proliferative and hypertrophic zones were outlined and, after calibration of the computer program, the zonal height was computed. Irrespective of whether the measures were taken from photomicrographs of the central or the peripheral region of the epiphyseal plate, results indicated higher generalizability coefficients for hypertrophic zone measurements than for those of the proliferative zone in seven of the eight intra-observer and inter-observer calculations. In addition, higher generalizability coefficients were achieved for intra-observer than for inter-observer measurement situations. It was concluded that this is a reliable technique if the sample is measured by one observer and the average of three repeated measurements is used for each specimen.