Quantitative segmental analysis of weight-bearing radiographs of the foot and ankle for children: normal alignment.

Clinical decision-making for the management of foot deformities in children is primarily based upon the analysis of weight-bearing radiographs of the foot and ankle. However, a comprehensive quantitative technique for the analysis of such radiographs has not been described. Ten radiographic measurements were developed and applied to the foot and ankle radiographs of a normal foot and ankle in 60 children (mean age 10 years, range 5-17 years). Intraobserver variability and interobserver variability were determined for 10 cases. Mean values for the 10 measurements were calculated from the entire study group. Intraobserver variability was excellent, with correlation coefficients for the 10 measurements ranging from 0.89 to 0.99. The absolute value of the mean differences in angular measurements ranged from 0.8 to 2.5 degrees. Interobserver variability was also excellent, with correlation coefficients ranging from 0.86 to 0.99. The absolute value of the mean differences in angular measurements ranged from 0.5 to 3.2 degrees. The mean values, standard deviations, and ranges for the 10 radiographic parameters from the 60 normal feet have been determined. Clinically acceptable variability of 10 selected radiographic measurements of the foot and ankle was achieved, and normal values and ranges for these measurements were determined. Quantitative segmental analysis of foot and ankle alignment, using these 10 radiographic measurements, can be used to describe common malalignment patterns, and this may assist in clinical decision-making and assessment of outcome.