Interobserver and Intraobserver Reliability in Lower-Limb Deformity Correction Measurements

Abstract

Planning for surgical correction of lower-limb deformity requires assessment of the character and extent of the deformity. Deformity measurements are defined; however, the reliability of these measurements has not been evaluated. This study was conducted to assess the interobserver and intraobserver reliability of lower extremity deformity measurements in the frontal and sagittal planes. Anteroposterior and lateral lower extremity radiographs were evaluated using Paley technique. Statistical analysis included intraclass correlation coefficient (2,1), median absolute difference, range, and agreement within 3 and 5 degrees. Reliability was good to very good for all measurements except for the anterior distal tibial angle, which had moderate reliability. Intraobserver reliability was higher than interobserver reliability, and measurements in the frontal plane had better reliability than measurements in the sagittal plane. Overall, these measurements are a reliable method of assessing lower extremity deformity and should be used to guide treatment and monitor outcome.

Reliability of Digital Radiographs for Pediatric Lower Extremity Alignment

“…10 We used the guidelines of Portney and Watkins 11 to assess reliability, which are stricter criteria than those used in many papers evaluating similar digital radiographic measurements. 1,2,15 These studies used different reliability criteria, and if these had been employed in the current study, the reliability would have been good to excellent. The stricter criteria were chosen for evaluation given the strength of reliability found for standard radiographs by Gordon et al 10 We did observe 2 specific errors with the computerbased measurements.…”

Recurrence of axial malalignment after surgical correction in congenital femoral deficiency and fibular hemimelia

“…Our study shows multiple biases. To account for errors in position during radiography and angle measurement, we chose an MAD change of a minimum of 5 mm for defining recurrence [23,24]. The number of cases included combined with multiple variables influencing recurrence resulted in a low statistical significance.…”

“…The change of the axial alignment was categorised in each patient who presented an MAD change of ≥5. Cases with MAD change <5 mm were not included in order to minimise bias of minor positioning errors, especially with respect to the rotational position of the limb during the radiograph [23] and the intraobserver variability [24].…”

Lower Limb Alignment in Children

“…The perceived lower limb malalignment can be either physiological or secondary to a variety of congenital and acquired etiologies. 4 This radiographic technique is reproducible 12,13 and is more accurate than clinical methods for assessing frontal plane deformities of the lower limb. They reported pronounced varus TFA at birth with progressive change to valgus alignment by 3 years in most children.…”