Ankle foot orthosis improves muscle oxygenation in patients with peripheral artery disease

Advisor Information

Sara Myers

Location

MBSC 201

Presentation Type

Poster

Start Date

6-3-2020 12:30 PM

End Date

6-3-2020 1:45 PM

Abstract

Introduction

Peripheral artery disease (PAD) manifests from blockages of the leg arteries that reduce blood flow. Claudication, a cramping pain or tiredness in the ischemic legs, is the most prevalent symptom of PAD. Previous studies have shown that resting muscle oxygenation is significantly lower and declines faster in the calf muscles of patients with PAD compared to healthy controls. An ankle foot orthosis (AFO) can improve functional status and quality of life in patients with PAD by decreasing muscle demand through absorbing and returning mechanical force during push-off. The purpose of this study was to measure muscle oxygenation of the gastrocnemius muscle in patients with PAD during walking with and without AFO.

Methods

A muscle oxygen monitor (PortaMon) was attached to gastrocnemius muscle of the subjects (n=7) while performing a standardized graded treadmill test to measure the tissue (muscle) oxygen saturation, StO2. The initial claudication time (ICT; pain onset) and absolute claudication time (ACT; time when the subjects stopped walking due to claudication pain were recorded. The subjects repeated the same test protocol twice, once without and once while wearing the AFO.

Results and Discussion

The StO2 values at ICT and ACT were significantly increased by 36.97% (p = 0.016) and 30.19% (p = 0.029) respectively while walking wearing AFO compared to without AFO. This suggests that using the AFO will enables the muscles to keep more of the oxygen delivered to working muscles, which also enabled longer ICT and ACT distances. Future studies should determine how StO2 impacts muscle activity, lower extremity torque and power, and energy cost.

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Mar 6th, 12:30 PM Mar 6th, 1:45 PM

Ankle foot orthosis improves muscle oxygenation in patients with peripheral artery disease

MBSC 201

Introduction

Peripheral artery disease (PAD) manifests from blockages of the leg arteries that reduce blood flow. Claudication, a cramping pain or tiredness in the ischemic legs, is the most prevalent symptom of PAD. Previous studies have shown that resting muscle oxygenation is significantly lower and declines faster in the calf muscles of patients with PAD compared to healthy controls. An ankle foot orthosis (AFO) can improve functional status and quality of life in patients with PAD by decreasing muscle demand through absorbing and returning mechanical force during push-off. The purpose of this study was to measure muscle oxygenation of the gastrocnemius muscle in patients with PAD during walking with and without AFO.

Methods

A muscle oxygen monitor (PortaMon) was attached to gastrocnemius muscle of the subjects (n=7) while performing a standardized graded treadmill test to measure the tissue (muscle) oxygen saturation, StO2. The initial claudication time (ICT; pain onset) and absolute claudication time (ACT; time when the subjects stopped walking due to claudication pain were recorded. The subjects repeated the same test protocol twice, once without and once while wearing the AFO.

Results and Discussion

The StO2 values at ICT and ACT were significantly increased by 36.97% (p = 0.016) and 30.19% (p = 0.029) respectively while walking wearing AFO compared to without AFO. This suggests that using the AFO will enables the muscles to keep more of the oxygen delivered to working muscles, which also enabled longer ICT and ACT distances. Future studies should determine how StO2 impacts muscle activity, lower extremity torque and power, and energy cost.