Characteristics of clinical measurements between biomechanical responders and non-responders to a shoe designed for knee osteoarthritis

doi:10.1016/j.gaitpost.2017.09.038

Gait & Posture

Volume 59, January 2018, Pages 23-27

https://doi.org/10.1016/j.gaitpost.2017.09.038 Get rights and content

Highlights

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The mobility shoe significantly reduced the knee adduction moments (KAM).
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22/64 knees showed no change or increased KAM, denoting responders/non-responders.
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Both hip rotation range and strength ratios could discriminate between the groups.
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Hip assessments may identify responders and non-responders to footwear for knee OA.

Abstract

Purpose

The purpose of this study was to investigate the characteristics of biomechanical and clinical measurements in relation to the knee adduction moment when wearing a standard shoe and a shoe design for individuals with knee osteoarthritis (Flex-OA).

Methods

Kinematic and kinetic data were collected from thirty-two healthy individuals (64 knees) using a ten camera motion analysis system and four force plates. Subjects performed 5 walking trials under the two conditions and the magnitude of individuals’ biomechanical responses where explored in relation to the clinical assessment of the Foot Posture Index, hip rotation range, strength of hip rotators, and active ankle-foot motion, all of which have been described as possible compensation mechanisms in knee osteoarthritis.

Results

Significant reductions in the first peak of the knee adduction moment (KAM) during stance phase (9.3%) were recorded (p < 0.0001). However, despite this difference, 22 of 64 knees showed either no change or an increased KAM, indicating a non-response or negative-response to the Flex-OA shoe. Significant differences were observed between the responder and non-responder subgroups in the hip rotation range ratio (p = 0.044) and the hip rotators strength ratio (p = 0.028).

Conclusion

Significant differences were seen in clinical assessments of hip rotation range and hip rotator strength between responders and non-responders using a cut-off of 0.02 Nm/kg change in the KAM.

Introduction

Knee osteoarthritis (OA) is the most prevalent disease amongst individuals aged 50 years and older in South Korea, affecting approximately 12.5% [1]. Clinical characteristics of knee OA are: pain, decreased range of motion, joint instability, muscle weakness, joint stiffness, and proprioceptive loss, all of which decrease quality of life [2].

The knee adduction moment (KAM) during walking in patients with degenerative knee OA has been discussed in previous studies [3], [4], [5], [6]. The KAM is primarily calculated by the ground reaction force and its lever arm. The KAM contributes to adduction of the knee and genu-varus deformities, which are significantly correlated with OA severity [7]. Therefore, reduction of the external KAM during walking is clinically important for treatment of OA. Biomechanical interventions such as: orthotic shoe inserts [8], knee braces [9], [10], and specialized footwear [11], [12], [13], [14] for knee OA aim to improve pain, decrease joint loading, and delay disease progression.

Over the past two decades, specialized footwear has been developed for the potential conservative management of knee OA [12]. Recently, Shakoor et al. reported that, following use of specialized mobility footwear, the Flex-OA shoe, the KAM was reduced by 18% compared to use of the participants’ own shoe [14]. Although the Flex-OA shoe had a significant effect on KAM, no study has explored whether this effect is universal or whether responder and non-responder groups may exhibit differences in clinical and biomechanical measurements. Therefore, the purpose of this study was to explore differences in KAM in a healthy population when wearing a standard shoe and the Flex-OA shoe, and to investigate the characteristics of individuals’ responses from biomechanical and clinical assessments.

Section snippets

Participants

This study recruited 32 healthy volunteers who consented to participate in the study and met the selection criteria. There were twenty-four males and eight females in the study population. Participants were given a detailed explanation of the study procedure and written informed consent was obtained. This study was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the STEMH Ethics Committee of the University of Central Lancashire (STEMH 347).

Results

The mean of walking speed in both the Flex-OA shoe and the standardised shoe of all participants were 1.435 ± 0.126 m/s, and 1.433 ± 0.142 m/s, respectively and there was no significant difference in walking speed between shoe conditions (p = 0.811). Significant differences were observed in the KAMs between conditions and knee sides in various stance phases (Table 1). The first peak of the KAM during loading (0–25% of stance phase) showed that the Flex-OA shoe condition significantly decreased KAM for

Discussion

We observed that, in 32 subjects, 22 of 64 healthy knees, experienced negative or minimal effect on KAM during walking when wearing the Flex-OA shoe. Therefore, this study examined whether clinical and biomechanical measurements could distinguish between KAM response/non-response subgroups in healthy individuals.

The clinical and biomechanical measurements used in the study were directly related to the coronal and transverse planes, which are arguably the most important considerations for

Conflict of interest statement

We can confirm that there is no conflict of interests for any of the authors.

Acknowledgments

The shoes were supplied by DJO Global, Inc. The suppliers played no role in the design, execution, analysis and interpretation of the data or writing of this study. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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Original articleCharacteristics of clinical measurements between biomechanical responders and non-responders to a shoe designed for knee osteoarthritis

Highlights

Abstract

Purpose

Methods

Results

Conclusion

Introduction

Section snippets

Participants

Results

Discussion

Conflict of interest statement

Acknowledgments

J. Biomech.

Osteoarthr. Cartil.

Clin. Biomech.

J. Biomech.

Knee

Gait Posture

Clin. Biomech.

Osteoarthr. Cartil.

Clin. Biomech.

Clin. Biomech.

Gait Posture

Phys. Ther. Sport

Gait Posture

J. Orthop. Res.

Gait Posture

The influence of exercise on an unstable surface on the physical function and muscle strength of patients with osteoarthritis of the knee

J. Phys. Ther. Sci.

Quadriceps strength and osteoarthritis progression in malaligned and lax knees

Ann. Intern. Med.

Knee joint loading differs in individuals with mild compared with moderate medial knee osteoarthritis

Arthritis Rheum.

The relationship between the load on the knee joint during walking and the biomechanical characteristics of single-leg standing

J. Phys. Ther. Sci.

Original article
Characteristics of clinical measurements between biomechanical responders and non-responders to a shoe designed for knee osteoarthritis