Wound measurement: the comparative reliability of direct versus photographic tracings analyzed by planimetry versus digitizing techniques.

Abstract

To investigate two methods of wound measurement (planimetry and digitizing) performed on two routinely used techniques of clinical wound assessment, tracings taken directly from a patient's wound (raw tracing) and from photographs of the wound (photographic tracing). We examined the level of repeatability and thus reliability of these methods, and determined if absolute measured wound size differed between the combinations of method and assessment procedures. Seven patients (4 women, 3 men; mean age +/- standard error of the mean = 63.1+/-5.0yrs) with a total of 11 wounds. Patients attended a podiatry outpatient department on two separate days for raw and photographic tracing of their wounds. For both of these trace types, a series of repeated recordings were conducted by a single investigator using planimetry and digitizing measurement methods. Independent statistical analyses (analysis of variance, p < .05) were conducted on logged coefficients of variation and logged means data to investigate for repeatability and for size differences, respectively. Planimetry produced a significantly larger degree of variability (thus less repeatability) than digitizing (p = .02) and also produced smaller readings (p = .00001). Averaging over methods also indicated that photographic tracings produced smaller readings than raw tracings (p = .019). For the wound sizes and shapes examined, tracings taken directly from the patients were found to be an inexpensive clinical and research assessment tool on which digitizing was conducted with a higher level of repeatability than planimetry. Further research is needed to determine if the current findings apply to a wider population within wound management clinics.