A study by Jelsing et al. (2013) examined whether the ITB moves relative to the lateral femoral epicondyle (LFE) as a function of knee flexion in both non–weight-bearing and weight-bearing positions in asymptomatic recreational runners. Evaluation using ultrasound on the ITBs of 20 male and female asymptomatic recreational runners clearly showed an anteroposterior motion of the ITB relative to the LFE during knee flexion-extension. The ITB does, in fact, move relative to the femur during the functional ranges of knee motion.
Jelsing, E. J., Finnoff, J. T., Cheville, A. L., Levy, B. A., & Smith, J. (2013). Sonographic Evaluation of the Iliotibial Band at the Lateral Femoral Epicondyle Does the Iliotibial Band Move?. Journal of Ultrasound in Medicine,32(7), 1199-1206.