Elsevier

Journal of Biomechanics

Volume 129, 2 December 2021, 110740
Journal of Biomechanics

Trunk lean and toe out gait strategies impact on lower limb joints

https://doi.org/10.1016/j.jbiomech.2021.110740Get rights and content

Abstract

Gait retraining as a non-invasive prospective approach to restore mechanical loading at the knee joint and slowing down knee osteoarthritis (OA) progression shows great promise. However, the impact of gait modifications such as an increase in foot progression angle (FPA) or lateral trunk lean (LTL) on the ankle and hip is not yet well understood. Thus, the goal of this study is to provide insight on the impact of FPA and LTL on the sagittal and frontal external moments at the ankle and hip of healthy participants. We hypothesize that there is an optimum, for which an increase in FPA and/or LTL minimize the knee adduction moment (KAM) without increasing significantly the frontal and sagittal external moments at the ankle and hip during gait. To test this hypothesis, 23 participants performed walking trials with modified FPA and/or LTL angles following a real-time visual feedback. The hypothesis was not confirmed and while not all the gait modifications performed by the participants in this study reduced the KAM, they significantly increased the sagittal moment at the ankle and the frontal moment at the hip. This study highlights the importance to consider the biomechanical consequences of gait modifications on the ankle and hip before considering a clinical application of gait retraining approaches.

Introduction

Knee osteoarthritis (OA) is the leading cause of disability among elderly, resulting in pain, limited daily activities and decreased quality of life (Sharma, 2021). To date, no known cure or proven strategy exists for slowing progression from early to end-stage knee OA (Steultjens et al., 2001, Baar et al., 2001). Consequently, therapy is limited to physical exercises, symptom relief and in advanced stages, joint replacement surgery (Bannuru et al., 2019). Knee OA development and progression, like other sites of OA, is a slow, heterogeneous and multifactorial process due to an interrelation of mechanical, biological and structural pathways causing the cartilage to degenerate (Andriacchi et al., 2004). Mechanically, overloading of the medial knee compartment has been associated with knee OA progression and radiographic disease severity (Miyazaki et al., 2002). Medial-to-lateral knee joint loading measurement being invasive, the external knee adduction moment (KAM) has been validated and employed as a surrogate (Birmingham et al., 2007, Foroughi et al., 2009). The external KAM is characterized by two peaks, the first and generally largest peak occurs during the load acceptance phase of early stance, while the second peak occurs during the propulsion phase of late stance (Simic et al., 2011). The KAM is now recognized as a marker of knee OA. Therefore, gait retraining, a prospective non-invasive approach, is aiming to reduce pain and restore mechanical loading in the knee joint by decreasing the first or second peak of KAM by modifying the gait pattern (Simic et al., 2011, Bowd et al., 2019, Hunt et al., 2011, Simic et al., 2012, Shull et al., 2013, Bowd et al., 2019, Mazzoli et al., 2019). Lateral trunk lean (LTL) and a decreased foot progression angle (FPA) are two gait modifications that have been shown to decrease the first peak of KAM, while an increase in FPA has been shown to decrease the second peak of KAM (Bowd et al., 2019, Simic et al., 2011, Richards et al., 2017). Moreover, it has been suggested that various combinations of FPA and LTL may result in greater KAM reduction or may be preferred by patients compared to single gait modifications (Shull et al., 2013, Fregly et al., 2007, Shull et al., 2011). FPA and LTL gait modifications in the literature have been delivered through visual (Simic et al., 2012, Simic et al., 2011, Hunt et al., 2018) or haptic (Uhlrich et al., 2019, Shull et al., 2013, Shull et al., 2011) feedback. The feedback either gave information about the movement to perform (Lindsey et al., 2020, Uhlrich et al., 2019, Shull et al., 2013, Shull et al., 2011, Simic et al., 2012, Simic et al., 2011, Hunt et al., 2018) or directly on the KAM amplitude (Wheeler et al., 2011, van den Noort et al., 2015), always with the aim of decreasing the first or second peak of KAM during gait. However, most gait interventions report large subject to subject variations of FPA or LTL (Shull et al., 2013, Shull et al., 2011, Chang et al., 2007, Mündermann et al., 2008), which complicates a statistical analysis of their impact. Moreover, while the impact of FPA and LTL on the KAM are well documented (Hunt et al., 2011, Simic et al., 2012, Shull et al., 2013, Hunt et al., 2008, Jenkyn et al., 2008, Ogaya et al., 2015), the impact on the frontal and sagittal external moments at the ankle and hip are less documented, as summarized in the systematic review by Bowd et al. (2019). Therefore, for the same reasons gait retraining could be very effective for slowing knee OA progression, it could negatively affect the hip (Kettlety et al., 2020) or ankle (Richards et al., 2017, Charlton et al., 2019) if it were to increase loading during gait. Indeed, it has been suggested that an increase in loading rate at the ankle or hip could lead to the onset or faster progression of OA at these joints (Simic et al., 2011). Therefore, the need exists to better comprehend the mechanical loading changes taking place at the lower limb joints when modifying the gait pattern. Before gait retraining for knee OA patients can transition to clinical practice, an understanding of the impact on the neighbouring joints is necessary. Moreover, to isolate the gait modifications from other compensations, the impact on healthy participants must first be evaluated. Thus, the goal of this study is to provide insight on the impact of FPA and LTL on the sagittal and frontal external moments at the ankle and hip of healthy participants. We hypothesize that there is an optimum, for which an increase in FPA and/or LTL minimize the KAM without increasing significantly the frontal and sagittal external moments at the ankle and hip during gait.

Section snippets

Participants

A total of 23 healthy participants aged between 30 and 45 years old (age: 35.6±5.10y.o.; height: 1.73±0.09m; weight: 74.4±12.60kg, 10 women) were included in this study. Exclusion criteria included lower limb joints pain and any disorder impacting walking ability or balance. Written informed consent was obtained for all participants and the project was approved by the local ethics committee (CER-S 2016-499).

Kinematics and kinetics

The participants were equipped with reflective markers on both lower limbs and the

Results

Among the 23 participants, the data of 21 were included in this study. Two participants were not able to perform enough successful gait cycles to be included in order to preserve a balanced statistical analysis. Participants performed the walking tasks with a mean speed of 1.04±0.09ms1 ranging from 0.8 to 1.2ms1. The mean FPA and mean maximum LTL angles during the different walking conditions are summarized in Table 1.

Discussion

This study was performed to provide more insight into the impact of an increase in FPA and/or LTL on the sagittal and frontal external moments at the ankle and hip. To our knowledge, this study is the first to control the amplitude of FPA and LTL in combination during gait. Twenty-one out of 23 participants were able to successfully change their gait pattern in a matter of minutes following two visual feedback at the same time.

The hypothesis that an optimum where the KAM is minimized while the

Conclusion

In conclusion, to our knowledge, this is the first study to control the amplitude of a combination of FPA and LTL and to look at the impact of such gait modifications on the ankle and hip sagittal and frontal external moments along the entire stance phase. This study highlights the importance to consider the biomechanical consequences of gait modifications on the ankle and hip before considering a clinical application of gait retraining approaches.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by the Natural Sciences and Engineering Research Council of Canada (CRSNG-2016-06001). The study sponsor had no involvement in the study design; in the collection, analysis or interpretation of data; in the writing of the manuscript; nor in the decision to submit the manuscript for publication.

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  • Cited by (0)

    1

    Kinesiology Department, Université Laval, 2300 rue de la Terrasse, G1V 0A6, Québec, Canada.

    2

    Mechanical Department, Université Laval, 1065 av. de la Médecine, G1V 0A6, Québec, Canada.

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