Figure 1: Used markersets
An appropriate knee stability plays an important role in the prevention of knee injuries and pain, especially in sports. In order to obtain information on knee stability, 3D movement analysis is often carried out during landings. Many different marker sets for motion and gait analysis are available for the analysis of the 3D biomechanics. The aim of this study was therefore to investigate the influence of six different, common marker sets (Figure 1) on the knee kinematics during the landing from a 40 cm high box in the oneleg stand.
The results show that only minor differences between the marker sets are found for the knee angles in the sagittal plane (Figure 2). In contrast, the knee angles in the transverse and frontal planes show partially opposite results. It can be clearly seen that for two marker sets a clear adduction is measured after ground contact. On the other hand, only abduction angles are determined for the RMS and RMS_oC marker sets after landing. In addition to the contrary courses, the extent of the movement differs. This is particularly evident in the transverse plane.
The results show that only minor differences between the marker sets are found for the knee angles in the sagittal plane (Figure 2). In contrast, the knee angles in the transverse and frontal planes show partially opposite results. It can be clearly seen that for two marker sets a clear adduction is measured after ground contact. On the other hand, only abduction angles are determined for the RMS and RMS_oC marker sets after landing. In addition to the contrary courses, the extent of the movement differs. This is particularly evident in the transverse plane.
Figure 2: Angle-time curve in the three planes for the six marker sets used
These differences can have a major impact on patient care. Depending on which marker set is used, contrary movements are detected and the patient's care is designed accordingly. Therefore, the choice of the marker set should be critically examined and methods should be developed that accurately measure movements especially outside the sagittal plane.