Reliability of measurements obtained by use of an instrument designed to indirectly measure iliotibial band length.

Ober's test is widely used to indirectly assess iliotibial band length on patients with painful conditions of the lower extremity. The validity of Ober's test is questioned on several accounts: there is no method for standardizing the position of the pelvis during the measurement; the scale used to describe the results is nominal and appears to have been arbitrarily determined; and, finally, the reliability of judgments made using Ober's test has not been reported. The purposes of this study were to develop a method for quantifying an indirect measurement of iliotibial band length and to examine the intratester and intertester reliability of measurements obtained. Iliotibial band lengths of 10 patients (N = 10) with anterior knee pain were measured twice by each of two examiners. Data were analyzed using the intraclass correlation coefficient (ICC) and standard error of the measurement (SEM). The ICC values were 0.94 and 0.73 for intratester and intertester reliability, respectively. The SEM values were 1 degree and 2 degrees for intratester and intertester reliability, respectively. Measurements obtained with the modified method are reliable when taken on young patients with anterior knee pain.