Estimation of ankle joint parameters in typically developed adults using functional calibration methods

[An update on clinical gait analysis : Current developments and applications]

The objective acquisition and assessment of joint movements and loads using instrumented gait analysis has become an established tool in clinical diagnostics. In particular, marker-based 3D gait analyses make use of an increasingly comprehensive database for the assessment of orthopaedic or neurological questions. Based on this data and medical-scientific experience, increasingly reliable approaches and evaluation strategies are emerging, which also draw on methods from artificial intelligence and musculoskeletal modelling. This article focusses on marker-based gait analyses of the lower extremity (hip, knee, foot) and how these can be used in a clinically relevant way using current methods, e.g. for determining indications or optimization of surgical planning. Finally, current developments and applications by using alternative methods from sensor technology and optical motion capture will be briefly discussed.

Achilles Tendon Loading during Running Estimated Via Shear Wave Tensiometry: A Step Toward Wearable Kinetic Analysis

PURPOSE

Understanding muscle-tendon forces (e.g., triceps surae and Achilles tendon) during locomotion may aid in the assessment of human performance, injury risk, and rehabilitation progress. Shear wave tensiometry is a noninvasive technique for assessing in vivo tendon forces that has been recently adapted to a wearable technology. However, previous laboratory-based and outdoor tensiometry studies have not evaluated running. This study was undertaken to assess the capacity for shear wave tensiometry to produce valid measures of Achilles tendon loading during running at a range of speeds.

METHODS

Participants walked (1.34 m·s -1 ) and ran (2.68, 3.35, and 4.47 m·s -1 ) on an instrumented treadmill while shear wave tensiometers recorded Achilles tendon wave speeds simultaneously with whole-body kinematic and ground reaction force data. A simple isometric task allowed for the participant-specific conversion of Achilles tendon wave speeds to forces. Achilles tendon forces were compared with ankle torque measures obtained independently via inverse dynamics analyses. Differences in Achilles tendon wave speed, Achilles tendon force, and ankle torque across walking and running speeds were analyzed with linear mixed-effects models.

RESULTS

Achilles tendon wave speed, Achilles tendon force, and ankle torque exhibited similar temporal patterns across the stance phase of walking and running. Significant monotonic increases in peak Achilles tendon wave speed (56.0-83.8 m·s -1 ), Achilles tendon force (44.0-98.7 N·kg -1 ), and ankle torque (1.72-3.68 N·m·(kg -1 )) were observed with increasing locomotion speed (1.34-4.47 m·s -1 ). Tensiometry estimates of peak Achilles tendon force during running (8.2-10.1 body weights) were within the range of those estimated previously via indirect methods.

CONCLUSIONS

These results set the stage for using tensiometry to evaluate Achilles tendon loading during unobstructed athletic movements, such as running, performed in the field.

Modeling foot rockers via functional calibration for use in clinical gait analysis

BACKGROUND

Goal of this work is a quantitative description of Jacquelin Perry's rocker concept by locating the position of the heel rocker and the forefoot rocker within segments of the foot via functional calibration.

METHODS

Two functional calibration tasks with the foot in ground contact were performed by ten typical developed adults and foot marker motion was captured. After applying a least-square method for constructing foot segments, their motion relative to the floor was analyzed via a functional algorithm. Resulting reference positions - namely the heel rotation center and the metatarsal rotation axis - were calculated. Further, the repeatability of the method and variability of outcome within the cohort was tested.

RESULTS

The heel rotation center is located substantially posterior (25 mm) and slightly more inferior (5 mm). to the midpoint of the two markers placed medially and laterally on the calcaneus. Repeated measures reveal a variation of this location around 5 mm. The forefoot center is slightly more medial to the "toe marker" (DMT2) and substantially more inferior (19 mm). The metatarsal rotation axis is slightly tilted in the frontal and transverse plane against the metatarsal line given between markers on MT1 and MT5 with small variation in repeated measures (1-2°).

SIGNIFICANCE

The determination of heel rotation center and the metatarsal rotation axis relative to foot segments can be determined with good repeatability and their location meet the intuitive expectation. Since they have a direct biomechanical meaning in the foot roll-over process in gait, they may be used for a more functionally oriented definition of foot segments potentially improving the calculation of foot kinematics and kinetics in future work.

Estimation of a midfoot joint center in typically developed adults using functional calibration methods

BACKGROUND

There are detailed findings on hip and knee joint parameters determined via functional calibration methods for use in instrumented 3D-gait analysis but these methods have not yet been addressed to the foot.

RESEARCH QUESTION

Are functional calibration methods feasible for determining foot joint parameters and may they help for clinical interpretation of foot deformities?

METHODS

Rigid segments were formed by markers on forefoot and hindfoot via a least square method. The position of the midfoot joint articulating both foot segments was then determined via a functional calibration motion. This two-stage procedure was applied on a cohort of 17 typically developed adults and one subject with severe planovalgus foot deformity for determining the location of the midfoot joint and kinematics of hindfoot and forefoot.

RESULTS

The position of the midfoot joint center could be estimated in the typically developed cohort and also in the demonstration case with planovalgus foot deformity. Depending on the choice of marker set for hindfoot and forefoot, the position of the joint center varied in the anatomic midfoot region with most robust results when addressing the marker on the navicular to the hindfoot.

CONCLUSION

The presented method for joint center determination within the foot and the characteristic results of the foot joint angles appear promising for typically developed feet. However, further validation of the method is needed for application in clinical context.

Focusing on functional knee parameter determination to develop a better clinical gait analysis protocol

BACKGROUND

Attempts to improve protocol standards of marker-based clinical gait analysis (CGA) have been one of the main focuses of research to enhance robustness and reliability outcomes since the 1990s. Determining joint centres and axes constitutes an important aspect of those protocols. Although the hip joint is more prominent in such studies, knee joint center (KJC) and axis (KJA) directly affect all outcomes.

RESEARCH QUESTION

What recommendations arise from the study of the scientific literature for determining knee joint parameters (KJP) for protocols of CGA?

METHODS

A systematic, electronic search was conducted on November 2018 using three databases with the keyword combination ("functional approach" OR "functional method" OR "functional calibration") AND ("hip joint" OR "knee joint" OR "ankle joint") and analyzed by four reviewers. Given the existence of a recent review about the hip joint and the lack of material about the ankle joint, only papers about the knee joint were kept. The references cited in the selected papers were also screened in the final round of the search for these publications. The quality of the selected papers was assessed and aspects regarding accuracy, repeatability, and feasibility were thoroughly considered to allow for a comparison between studies. Technical aspects, such as marker set choice, KJP determination techniques, demographics, and functional movements, were also included.

RESULTS

Thirty-one papers were included and on average received a rating of about 75 % according to the quality scale used. The results showed that functional methods are superior or equivalent to predictive methods to estimate the KJA, while a regression method was slightly better for KJC prediction.

SIGNIFICANCE

Calibration methods should be applied to CGA whenever feasibility is reached. No study to date has focused on evaluating the in vivo RoM required to obtain reliable and repeatable results and future work should aim in this direction.