Hip centralizing forces of the iliotibial tract within various femoral neck angles.

A contentious issue in the literature is the function and the biomechanical properties of the iliotibial tract. On account of this fact the aim was to take a measurement about the hip centralizing forces of the iliotibial tract by using a custom-made hip prosthesis with adjustable femoral neck angles and lengths in an anatomic model. By increasing the collodiaphyseal (CCD) angle (coxa valga) a higher load of the hip joint results. Decreasing the CCD angle (coxa vara) leads to a lower load of the hip joint. In the case of lengthening the femoral neck we saw a considerable increase of the forces along the femoral neck. Furthermore, we registered intraoperatively the subligamentous forces of the iliotibial tract in the height of the greater trochanter to analyse the axial forces into the acetabular cavity. The iliotibial tract showed increasing forces within adduction as well as decreasing forces within abduction of the hip joint. The clinical relevance consists of the predictability of the increasing or decreasing tension band wiring effect of the iliotibial tract in correlation to the CCD angle. The measurement gives the clinical users a benchmark for the expected subligamentous forces of the iliotibial tract and the resulting hip centralizing forces.