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Sato A1, Yamada T2
1Edogawa Hospital, Department of Rehabilitation, Tokyo, Japan, 2Tokyo Metropolitan University, Tokyo, Japan
Background: An ankle inferior knee osteoarthritis short ankle orthosis (Agilium Freestep (Agilium), Ottobock (Germany)) has been prescribed in more than 6,000 patients with knee osteoarthritis worldwide. Previous studies have reported that by walking with Agilium, the center of pressure (CopX) moved to the outside and knee adduction moment (KAM) instantaneously decreased.
Purpose: We measured CopX, KAM, and the floor reaction force in the frontal plane (Force X) without (control) and with Agilium, and examined the relationship with flat feet.
Methods: The subjects were 17 healthy young adults (9 men, 8 women, 22.1 ± 0.5 years old). A 4-force plate and 12 camera 3D Motion Capture system (Vicon and Nexus software) was used in this study. Standing position and walking were measured with and without Agilium. CopX, ForceX, KAM, and knee varus angle were obtained.
Furthermore, in order to evaluate flat feet of the subject, the height (mm) from the floor surface to the navicular bone rough surface and the length (mm) from the end of the calcaneus to the head of the first metatarsal bone were measured. The Bony Arch Index was calculated by dividing the height by the length (arch ratio), and was classified as a flat foot if it was 0.21 or less.
In order to compare the changes without and with Agilium, we applied the t test. In order to investigate the relation between the arch ratio and CopX, ForceX, KAM, knee varus angle, and without and with Agilium installation, two-way analysis of variance (ANOVA) was performed. Study was conducted with the approval of the Research Safety Ethics Review Committee of the Tokyo Metropolitan University.
Results: The t-test showed that during standing, CopX and ForceX increased significantly (p 0.01) both on the left and right when Agilium was attached. A significant decrease was observed in the left and right knee varus angles (p 0.05). There was no significant difference in KAM. A significant decrease in knee varus angles was seen only in the right knee during walking (p 0.05).
ANOVA showed the right and left foot CopX and ForceX in the standing position, the main effect of the Agilium was significantly recognized (p 0.01). The interaction between the arch ratio and the Agilium was significant at the left KAM during walking (p 0.05). In the group not having flat feet, the left KAM during walking was significantly reduced by Agilium (p 0.01).
Conclusion(s): We found that the arch ratio affects CopX, ForceX, and KAM when Agilium is used.
Implications: Further research is needed to clarify the relationship with the arch ratio, and actual use in patients with knee osteoarthritis.
Keywords: Short ankle orthosis, knee osteoarthritis
Funding acknowledgements: The authors have no conflicts of interest directly relevant to the contact of this article.
Purpose: We measured CopX, KAM, and the floor reaction force in the frontal plane (Force X) without (control) and with Agilium, and examined the relationship with flat feet.
Methods: The subjects were 17 healthy young adults (9 men, 8 women, 22.1 ± 0.5 years old). A 4-force plate and 12 camera 3D Motion Capture system (Vicon and Nexus software) was used in this study. Standing position and walking were measured with and without Agilium. CopX, ForceX, KAM, and knee varus angle were obtained.
Furthermore, in order to evaluate flat feet of the subject, the height (mm) from the floor surface to the navicular bone rough surface and the length (mm) from the end of the calcaneus to the head of the first metatarsal bone were measured. The Bony Arch Index was calculated by dividing the height by the length (arch ratio), and was classified as a flat foot if it was 0.21 or less.
In order to compare the changes without and with Agilium, we applied the t test. In order to investigate the relation between the arch ratio and CopX, ForceX, KAM, knee varus angle, and without and with Agilium installation, two-way analysis of variance (ANOVA) was performed. Study was conducted with the approval of the Research Safety Ethics Review Committee of the Tokyo Metropolitan University.
Results: The t-test showed that during standing, CopX and ForceX increased significantly (p 0.01) both on the left and right when Agilium was attached. A significant decrease was observed in the left and right knee varus angles (p 0.05). There was no significant difference in KAM. A significant decrease in knee varus angles was seen only in the right knee during walking (p 0.05).
ANOVA showed the right and left foot CopX and ForceX in the standing position, the main effect of the Agilium was significantly recognized (p 0.01). The interaction between the arch ratio and the Agilium was significant at the left KAM during walking (p 0.05). In the group not having flat feet, the left KAM during walking was significantly reduced by Agilium (p 0.01).
Conclusion(s): We found that the arch ratio affects CopX, ForceX, and KAM when Agilium is used.
Implications: Further research is needed to clarify the relationship with the arch ratio, and actual use in patients with knee osteoarthritis.
Keywords: Short ankle orthosis, knee osteoarthritis
Funding acknowledgements: The authors have no conflicts of interest directly relevant to the contact of this article.
Topic: Human movement analysis; Orthopaedics
Ethics approval required: Yes
Institution: Tokyo Metropolitan University
Ethics committee: Research Safety Ethics Review Committee of the Tokyo Metropolitan University
Ethics number: 17067
All authors, affiliations and abstracts have been published as submitted.
