Intraobserver and interobserver agreements of leg circumference measurements by tape measure based on 3 reference points

Abstract

The objective of this study was to evaluate the intraobserver and interobserver agreements in tape measurements of the ankle and calf circumference with due emphasis on the 3 main reference points, the patella, the tibial tuberosity, and the medial malleolus. The leg circumference at 2 locations was measured in 66 patients in the mornings of 2 consecutive days by 6 observers. Finally, a blinded couple measured leg circumferences at a line created on calves with a ballpoint pen of 68 outpatients to calculate interobserver agreement for lined regions. Leg circumference measurement was accepted as correct when the difference was less than 0.6 cm in 2 occasions. Intraobserver and interobserver agreements were calculated as the percentage of correct measurements. Chi-square test was used to compare intraobserver and interobserver agreements for each reference point. At the calf region, intraobserver and interobserver agreements based on the tibial tuberosity (88% and 81 %) were better than those of the patella (65% and 57%) and the medial malleolus (73% and 65%). On the other hand, at above the ankle region, the agreements (79% and 62%) were also better than those of the patella (60% and 43%) and nearly the same as those of the medial malleolus (86% and 65%). Finally, interobserver agreement of the measurements at the created line with ballpoint pen (96%) was better when compared to those of the tibial tuberosity (81%), the patella (57%), and medial malleolus (65%) (p = 0.005, p < 0.001, and p < 0.001, respectively). The results of this study suggest that the tibial tuberosity as a reference point for leg circumference measurement has better intraobserver and interobserver agreements than those of the patella and the medial malleoli.