Marker cluster rigidity in a multi-segment foot model

Efficacy of quantifying marker-cluster rigidity in a multi-segment foot model: a Monte-Carlo based global sensitivity analysis and regression model

“…There is a lack of consensus on how the foot should be tracked or represented in MSFMs used in clinical gait analysis. An earlier study by Chan et al (2019) concerning the rigidity of the hindfoot, forefoot, and tibia segment suggested that the forefoot is the least rigid segment and questioned its rigid body assumption. Similar methods of utilising transformation residuals to compute marker-cluster rigidty were also used in previous studies to quantify the non-rigid motion of the soft tissue artefacts (van den Bogert et al, 1994;Grimpampi et al, 2014).…”

“…mid-foot and forefoot) may not be appropriate, potentially losing or misrepresenting important clinical information (Nester et al, 2010;DiLiberto et al, 2015;Pothrat et al, 2015). This is particularly true for the forefoot segment, with a number of studies questioning the validity of assuming a single segment forefoot (Wolf et al, 2008;Rouhani et al, 2011;Chan et al, 2019) and a review confirming the lack of consensus on how it is currently tracked (Rankine et al, 2008). Lower-limb segments that may reasonably be assumed to act as a single bony entity such as the thigh and pelvis also are liable to soft tissue artefacts (STA), where movement of the soft tissues causes the skin-attached markers to move relative to the underlying bone (Leardini et al, 2005).…”

“…It represents the difference between two geometries (here, of the markerclusters). In the past, studies have utilised residuals to quantify the non-rigid motion of the soft tissue artefact (van den Bogert et al, 1994;Grimpampi et al, 2014), minimise rotation error (Leitch et al, 2010), and quantify MSFM segment rigidity (Spoor and Veldpaus, 1980;Bruening et al, 2012;Chan et al, 2019), but they have yet to show that it is an appropriate representation of the actual movement. To our knowledge, there is currently no study assessing the efficacy and validity of using the r RBE to quantity rigidity or deformation.…”