Analysis of a kinetic multi-segment foot model. Part I: Model repeatability and kinematic validity

Abstract

Kinematic multi-segment foot models are still evolving, but have seen increased use in clinical and research settings. The addition of kinetics may increase knowledge of foot and ankle function as well as influence multi-segment foot model evolution; however, previous kinetic models are too complex for clinical use. In this study we present a three-segment kinetic foot model and thorough evaluation of model performance during normal gait. In this first of two companion papers, model reference frames and joint centers are analyzed for repeatability, joint translations are measured, segment rigidity characterized, and sample joint angles presented. Within-tester and between-tester repeatability were first assessed using 10 healthy pediatric participants, while kinematic parameters were subsequently measured on 17 additional healthy pediatric participants. Repeatability errors were generally low for all sagittal plane measures as well as transverse plane Hindfoot and Forefoot segments (median<3°), while the least repeatable orientations were the Hindfoot coronal plane and Hallux transverse plane. Joint translations were generally less than 2mm in any one direction, while segment rigidity analysis suggested rigid body behavior for the Shank and Hindfoot, with the Forefoot violating the rigid body assumptions in terminal stance/pre-swing. Joint excursions were consistent with previously published studies.

A Three-Dimensional Multibody Model of the Human Ankle-Foot Complex

“…Only a few works address the patterns of the midtarsal joint. Bruening et al [4,5] presented recently an analogous model obtaining results that are similar to the ones obtained in this work. In particular, the analysis of the plantar/dorsiflexion enables the study of the spring like behavior of the longitudinal arch of the foot, which could be of particular interest in the study of neuropathologies and in the design of orthopaedic solutions.…”

Movement of the human foot in 100 pain free individuals aged 18¿45: implications for understanding normal foot function

“…It has a different number and definition of segments in the forefoot for example, although the same or similar anatomical landmarks are used to locate markers and cluster plate positions. Reliability of such foot models has been very well discussed in prior literature [27,[38][39][40], and since the anatomical landmarks and attachment approach we used is common to other models already reported, its reliability will not be notably different. It is worth noting that reports of foot model reliability include the effects of normal variability in gait kinematic data and standing position (used to establish 0°) due to collection of data in different sessions on the same day, and across different days.…”

Effect of static foot posture on the dynamic stiffness of foot joints during walking

“…The dynamics of the ankle, midtarsal and metatarsophalangeal joints of the right foot were registered using an adaptation of the model proposed by Bruening et al [24], as presented in Sanchis-Sales et al [11]. This model considered the midtarsal and metatarsophalangeal joints globally, not one particular midtarsal or metatarsophalangeal joint.…”