Application of Carbon Fiber Ankle Foot Orthoses to Enhance Gait Outcomes for Individuals with Neurologic Gait Dysfunction

Special Article – Gait Rehabilitation

Phys Med Rehabil Int. 2017; 4(4): 1123.

Application of Carbon Fiber Ankle Foot Orthoses to Enhance Gait Outcomes for Individuals with Neurologic Gait Dysfunction

Shearin SM*, Bauzaite E, Hall H and McCain KJ

Department of Physical Therapy, The University of Texas Southwestern, USA

*Corresponding author: Shearin SM, Department of Physical Therapy, The University of Texas Southwestern, 5323 Harry Hines Blvd, Dallas, TX 75239-8876, USA

Received: September 06, 2017; Accepted: October 05, 2017; Published: October 12, 2017

Abstract

Introduction: There is evidence that ankle foot orthoses (AFO) designs can impact gait outcomes for patients with neurologic dysfunction. Few studies have examined the benefits of different materials such as CF orthoses compared to plastic orthoses. This is a critical need in view of the difference in expense and complexity of fabricating CF AFOs compared to more traditional, less expensive polypropylene devices.

Objective: The purpose of this study is to highlight excellent gait outcomes resulting from transitioning individuals from polypropylene AFOs and peroneal nerve stimulators to custom-fabricated CF AFOs in individuals with neurological impairments.

Materials and Methods: The participants included 13 individuals with neurologic gait dysfunction who were transitions from polypropylene AFOs to custom-fabricated CF orthoses. All of these individuals were experienced users of previous devices, either polypropylene or peroneal nerve stimulator. In order to highlight the effects of the orthoses while minimizing the effects of the physical therapy interventions, each participant received between 1 and 4 physical therapy sessions with the new orthoses before the data was collected.

Results: All 13 participants demonstrated improvements in their step length and gait velocity from initial to final condition. Many of the participants experienced improved step symmetry as well.

Conclusions: The participants in this study showed a positive trend for improvements in step length, step length differential, and gait velocity with the use of the CF AFOs. This clinical tool has the potential to significantly augment the treatment of these individuals and is an important avenue of future research.

Keywords: Gait; Orthosis; Brace; Carbon fiber; Neurologic rehabilitation

Introduction

Ankle-foot orthoses (AFOs) are often prescribed for persons with neurological conditions to improve their quality of gait. There are many different designs of ankle foot orthoses as well as different materials that are utilized. Orthoses can be designed topromote dorsiflexion assistance, aid in knee stabilization, improve foot positioning and they may have the potential to enhance proprioceptive feedback. There is evidence in the literature that AFO designs can impact gait outcomes for patients with neurologic dysfunction. AFOs have been shown to increase walking speed, decrease energy expenditure, and positively impact stance phase as well as foot position [1-4]. Miyazaki also suggested that individual AFO design could significantly impact gait mechanicsas well as muscle activation secondary tothe external input afforded by the device [5]. Some AFO designs can supplement plantarflexion strength which provides critical stability in mid to late stance [5,6].

Currently, there are two commonly used types of bracing material, polypropylene (plastic) and carbon fiber (CF) as well as some commonly utilized orthosis designs. Polypropylene is a widely used material that is generally easy to work with and it is relatively inexpensive. Polypropylene has historically been used to fabricate posterior leaf spring, solid ankle, and double action AFOs. A posterior leaf spring AFO is effective for reducing foot drop/drag during swing phase and allows for some plantar flexion at loading response, but is not ideal for persons with posterior compartment weakness due to the lack of anterior stability [7]. Double action AFOs have been found to not only assist with dorsiflexion during swing, but also to allow for plantar flexion during loading response and even to assist in regaining plantarflexion strength after stroke [4]. Solid ankle AFOs, while still widely used, do function to aid dorsiflexion during swing but interfere with normal loading response by limiting plantar flexion. They also serve to limit tibial translation during stance, which interferes with a trailing limb and typical muscle activation (REF).

In contrast, CFis a less familiar material to orthotists and is more expensive than polypropylene. CF is thought to besuperior to polypropylene due to its energy storing capacity and lightweight quality. CF has been used to fabricate similar designs as polypropylene, such as the posterior leaf spring and solid ankle. There is evidence in the literature of using CF orthoses in persons with neurologic diagnoses.

Few studies have examined the benefits of CF orthoses compared to plastic orthoses. When assessed collectively, studies show that orthoses overall positively impacts gait in persons with neurologic injury, but clear clinical guidelines are unavailable due to the diversity of options studied and the lack of comparative studies. This is a critical need in view of the difference in expense and complexity of fabricating CF AFOs compared to more traditional, less expensive polypropylene devices. The current study is intended to add to the current body of knowledge in this area. The purpose of this study is to highlight excellent gait outcomes resulting from transitioning individuals from polypropylene AFOs and peroneal nerve stimulators to customfabricated CF AFOs in individuals with neurological impairments.

Case Description

Participants

The Institutional Review Board approved this retrospective data collection. The principle and co-investigators identified individuals from the School of Health Professions Neurologic Physical Therapy Gait Disorders Clinic with neurologic diagnoses who were treated with custom-fabricated CF ankle foot orthoses (unilateral or bilateral). The participants were retrospectively selected if their device was changed from a non-CF brace or peroneal nerve stimulator to a customfabricated CF orthosis. The principle and co-investigators reviewed the electronic patient physical therapy records from the School of Health Professions Neurologic Physical Therapy Gait Disorders Clinic to collect the data which was de-identified.

The group of participants included 13 individuals who were treated with custom-fabricated CF bracing and all had gait dysfunction. The individuals ranged in age from 19-76 years old. The participants’ diagnosis, years since diagnosis, age, gender, and number of treatments after orthosis fitting to data collection are listed in Table

1. Table 2 details the participants’ previous bracing (polypropylene or peroneal nerve stimulator), current CF bracing (unilateral or bilateral), as well as their initial and final assistive device use. All of these individuals were experienced users of previous devices, either polypropylene or peroneal nerve stimulator (> 6 months duration).