Two Different Protocols for Knee Joint Motion Analyses in the Stance Phase of Gait: Correlation of the Rigid Marker Set and the Point Cluster Technique

Abstract

Objective. There are no reports comparing the protocols provided by rigid marker set (RMS) and point cluster technique (PCT), which are similar in terms of estimating anatomical landmarks based on markers attached to a segment. The purpose of this study was to clarify the correlation of the two different protocols, which are protocols for knee motion in gait, and identify whether measurement errors arose at particular periods during the stance phase. Methods. The study subjects were 10 healthy adults. All estimated anatomical landmarks were which their positions, calculated by each protocol of the PCT and RMS, were compared using Pearson's product correlation coefficients. To examine the reliability of the angle changes of the knee joint measured by RMS and the PCT, the coefficient of multiple correlations (CMCs) was used. Results. Although the estimates of the anatomical landmarks showed high correlations of >0.90 (P < 0.01) for the Y- and Z-coordinates, the correlations were low for the X-coordinates at all anatomical landmarks. The CMC was 0.94 for flexion/extension, 0.74 for abduction/adduction, and 0.71 for external/internal rotation. Conclusion. Flexion/extension and abduction/adduction of the knee by two different protocols had comparatively little error and good reliability after 30% of the stance phase.

Kinematic analysis of knee varus and rotation movements at the initial stance phase with severe osteoarthritis of the knee

“…First, analyses of the rotational movement of the knee joint using motion analysis systems have associated problems in measurement precision according to skin movement artifacts [23,24]. The measurement method used in this study was confirmed to show repeatability in previous research by the authors [25], and also showed high correlations in comparisons with an existing measurement method (point cluster technique) [25]. Although the problem of whether the motion of the actual bone is reflected is still present, the non-invasive method used in this study is considered to produce reasonable results when compared with a previous study [26].…”

Comparison of six different marker sets to analyze knee kinematics and kinetics during landings

“…Six different common marker sets (Plug in Gait® (PiG) [4], rigid marker set with clusters (RMS) and without using clusters (RMS_oC) [5], six degree of freedom (6DOF) [6], Helen Hayes (HH) [6], functional approach (FAPA) [7]) were used. Therefore, 26 markers and two clusters were simultaneously attached to the subjects' lower limb and pelvis.…”

Test methods for exoskeletons—lessons learned from industrial and response robotics

“…Body Segment CM places a marker on each body segment. Various tests have used these and other marker placements measured by optical tracking systems to measure motion [26], bone bending [27], or to compare rigid marker sets to point clusters (see Figure 3 (b)) [28] [29] to estimate anatomical landmarks based on markers attached to a segment. The rigid marker sets are meant to limit measurement errors due to muscle and skin motion [30], although when using many markers as shown in Figure 3 (b), errors were minimized.…”

“…[23] and (b) Rigid (left) versus point cluster (right) marker sets being used to measure gait. [28] Of key importance to all of the previous references is the notion of how certain and reliable are the measurements and the techniques used to make the measurements. For example, in the above list of normal maximum rotations from [20], it is unknown how the measurements were made and therefore, how much uncertainty there is in each measurement noting that the angles are nearly all listed in 10° increments.…”

“…Similar to [23] who used light markers and film to measure joint rotation axis location, NIST researchers used reflective, passive markers and an optical tracking system of 12 cameras [37] to track the joint rotation. And similar to both [28] and [29], rigid marker artifacts (RMA) were used. Two 89 mm x 152 mm (3.5 in x 6 in) flat aluminum RMAs, each with four markers in unique patterns, were symmetrically mounted onto two 3D printed arcs that matched the robot links radius-of-curvatures.…”