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Biomechanics

Biplane Fluoroscopy Development of Improved Accuracy Ankle Joint Force Paradigm

(D-142) Biplane Fluoroscopy Development of Improved Accuracy Ankle Joint Force Paradigm

Friday, October 13, 2023

3:30 PM – 4:30 PM PDT

Location: Exhibit Hall - Row D - Poster # 142

Presenting Author(s)

IR

Isaac Ronning

Student Researcher
University of Calgary
Los Alamos, New Mexico, United States

Co-Author(s)

TB

Tomasz Bugajski

Post-Doctorate Trainee/Lab Manager
University of Calgary, United States

Last Author(s)

KR

Koren Roach

Assistant Professor
University of Calgary, United States

Introduction:: Approximately 79 million people globally suffer from ankle osteoarthritis (OA)[1]. Factors that may contribute to the development of ankle OA are abnormal joint kinematics and kinetics of the foot and ankle, which subsequently lead to abnormal loading of the enclosed cartilage. Despite the prevalence of ankle OA, there remains a lack of knowledge about joint loading in the foot and ankle. Foot kinetics are especially important to understand, as secondary OA often develops within the joints of the foot following ankle OA. Using conventional optical camera systems, multi-segment skin marker models have been used to estimate kinetics in the foot and ankle. However, these methods may suffer from skin motion artifacts and cannot differentiate motion between individual bones. Alternatively, biplane fluoroscopy (BF) may be used to directly measure individual bone motion, providing more accurate assessments of the foot and ankle joints. Currently, there is no standard protocol to measure the kinetics of each individual foot and ankle bone with BF. The objective of this study was to develop a method to determine foot and ankle kinetics based on previous work by Bruening et al. (2012) using a conventional multi-camera system, reflective markers, a force plate, and a pressure plate. This framework can then be adapted to an individual joint level using BF.

Materials and Methods::

One male participant was recruited for this feasibility study. A 10-camera motion capture system (Motion Analysis, USA ) was placed about a walkway with a force plate (AMTI, USA) overlaid with a pressure plate (Currex, USA) which recorded skin-marker trajectories (200 Hz), ground reaction forces (2000 Hz), and plantar pressures (200 Hz), respectively. Thirty reflective skin-markers were placed on bilateral lower-limbs of the participant following the Rizzoli foot model (Fig. 1) [2]. The participant performed two walking trials, one for each foot.

A custom script was developed to measure kinetics (MatLab, The MathWorks, USA). Specifically, skin-marker trajectories were used to calculate kinematics for the multi-segment model, which were verified through comparison to existing literature. By aligning the center of pressure (COP) from the force plate and pressure mat, the stance phase of gait was spatially matched to determine the distribution of the ground reaction forces (GRFs) underneath the foot. An inverse dynamics approach was then used to obtain foot and ankle kinetics, starting with the most distal segment receiving a GRF and moving proximally. Joint power absorbed and generated was calculated for each joint using joint moments and angular velocity, normalized to body weight, and qualitatively compared to previous work. An independent t-test compared power at 85% of stance with previous literature[3]. Joint power mean and standard deviation at 85% of stance was estimated from graphs reported by Bruening et al. (2012) and compared to current results using a t-test[3]. Significance was set at p< 0.05.

Results, Conclusions, and Discussions::

Results:
When examining sagittal plane power the ankle exhibits an absorption of power during heel strike before slight power generation, followed by a period of decreasing power before a large generation of power throughout push off (Fig 2.). There was no statistically significant difference in peak powers in the transverse (-0.07±0.05 vs -0.075 W/kg, p = 0.92), coronal (-0.15±0.09 vs -0.132 W/kg, p =0.84), or sagittal (2.1±0.6 vs 1.5 W/kg, p = 0.32) planes (Fig. 3).

Discussion:

We successfully developed a framework to calculate multi-segment foot join kinetics and verified our results to those reported in Bruening et al. (2012)[3]. The sagittal foot joint power generation and absorption results of the current study show similar profiles to Bruening et al. (2012)[3]. Additionally, our power results at 85% of stance fall within the standard deviation of values reported by existing literature [3]. In the continuation of this project, we will replace skin-markers with anatomical bone locations tracked via BF to decrease skin motion artifacts and skin-marker tracking difficulties. In doing so, ankle kinetic calculations should become more precise, thereby leading to an improved application of Newton's second law with inverse dynamics and a better understanding of ankle and foot kinetics due to GRFs.

Conclusion:

A custom code was successfully developed to measure ankle and foot kinetics via a multi-segment foot model that reports results similar to Bruening et al. (2012)[3]. The framework developed in this project to automatically measure ankle and foot kinetics from a multi-segment skin-marker foot model, with future BF application, provides a solid foundation fto increase our knowledge of internal foot and ankle biomechanics. With a better understanding of ankle and foot kinetics, preventative strategies for abnormal joint loading leading to OA can be developed, improving the lives of millions of people worldwide.

Acknowledgements (Optional): : We gratefully acknowledge funding support from the BME Summer Studentship from the McCaig Institute of Bone and Joint Health at the University of Calgary

References (Optional): :

[1]Herrera-Pérez M, Valderrabano V, Godoy-Santos AL, de César Netto C, González-Martín D, Tejero S. “Ankle osteoarthritis: comprehensive review and treatment algorithm proposal.” EFORT Open Rev. 2022 Jul 5;7(7):448-459. doi: 10.1530/EOR-21-0117.

[2] K. Deschamps et al., “Estimation of foot joint kinetics in three and four segment foot models using an existing proportionality scheme: Application in paediatric barefoot walking,” Journal of Biomechanics, vol. 61, pp. 168–175, 2017. doi:10.1016/j.jbiomech.2017.07.017

[3] Bruening DA, Cooney KM, Buczek FL. “Analysis of a kinetic multi-segment foot model part II: kinetics and clinical implications.” Gait Posture. 2012 Apr;35(4):535-40. doi: 10.1016/j.gaitpost.2011.11.012