The reliability and concurrent validity of lower leg circumferential assessment

Introduction

Two common methods of determining volume in clinical practice are water displacement and circumferential measurements. Most studies of circumferential measurement of the lower leg only assessed around the ankle, not the whole lower limb. Water displacement volume is considered as the "gold standard" for volumetric measurement of the limbs. However, girth measurements can be obtained easily in clinical practice. Therefore, the purpose of this study is to determine the inter-rater, intra-rater reliability, and concurrent validity of the circumferential measurement of the lower limb’s volume.

Methods

Twenty-three lower legs of 13 normal subjects (age: 22.3 ± 3.6 years; body height: 166.0 ± 11.1 cm; body weight: 59.7 ± 15.3 kg) were measured by 2 raters (A, B) with the circumferential measurement, and rater C administrated the test of water displacement. Each rater performed the measurement in the morning and evening in one day and the next day. The intra-rater and inter-rater reliability were analyzed using the intra-class correlation coefficient (ICC) statistic. The degree of concurrent validity was assessed using Pearson product moment correlation coefficient. Paired t-test was performed on the mean difference between two circumferential measures obtained by two raters or two repetition of the same rater to determine the presence of a systematic bias.

Results

The results were showed that ICC = 0.987 of intra-rater reliability and ICC = 0.989 of inter-rater reliability. There was excellent correlation between water displacement method and circumferential measurement technique (r = 0.971, p < .0001). There were no significance differences between two circumferential measures obtained by two raters or two repetition of the same rater (p > .05).
Discussion/Conclusions
The circumferential measurement technique is simple to administrate, has highly intra-rater and inter-rater reliability, and excellent correlate with the water displacement measurement. We suggest the circumferential measurement method is used in clinical setting to evaluate the lower leg volume. Because this method is friendly using, cost saving, and time efficiency.

References

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