Correction

After the publication of this work [1], we became aware of the fact that the description of the knee position for one of the measurements (dorsiflexion of the foot) was not correctly described. It was described as dorsiflexion of the foot with extended knee. The correct description is dorsiflexion of the foot with knee flexion. The presented results, discussion and conclusion are based on the position used (knee in flexion).

In the method section, see following paragraph: "In the present study all assessments of hip abduction, hip external rotation, popliteal angle, knee extension and dorsiflexion of the foot with knee flexion from the start 1994 until 1 January 2007 were included (Table 2)."

In Table 2. Goniometer positioning and standardization procedure for all five joint angles, Extremity position Foot dorsiflexion. Supine. Knee in flexion.