Reliability of photographic analysis in determining change in scar appearance

Photographs frequently are used to document change in the management of hypertrophic scars. The purpose of this study was to design a scale for the analysis of photographs of hypertrophic scars and to test its reliability. The subjects were four occupational and physical therapists, (two novices and two experts), in scar management. Existing scales were modified to produce a new scale. The subjects twice rated four slides from each of ten patients' scars, in random order. They used a Latin Square design. Interrater and test-retest reliabilities were calculated using a weighted kappa statistic. The newly developed scale demonstrated interrater reliability, which ranged between 0.66 and 0.90 for all items. The test-retest reliability ranged between 0.73 and 0.89 for all items. The new scale had substantial reliability (using a single rater) and was at least as reliable when used by novice therapists. This indicated that training had no effect.