Northwestern University Feinberg School of Medicine

Northwestern University Prosthetics-Orthotics Center

Effect of Ankle-Foot Orthoses (AFOs) on Continuous Walking in Persons with Post-Stroke Hemiplegia

Principal Investigator: Stefania Fatone, PhD, BPO(Hons)

Co-Investigators: Kristin Carnahan, MS, CPO; Rebecca Stine MS; Kurian Thomas, MD 

Research Assistant: Jessica Yohay, BS

Collaborating Site: Jesse Brown VA Medical Center

Status: In Progress

Acknowledgement: Supported by an American Orthotic and Prosthetic Association (AOPA) Research Award administered by the Center for Orthotics and Prosthetics Learning and Outcomes/Evidence-Based Practice.

Introduction

AFO footwear combinationsPost-stroke hemiplegia often results in impaired walking performance. To improve walking ability and reduce gait deviations an ankle-foot orthosis (AFO) may be prescribed. Although some previous research suggests that AFOs may provide greater benefit when individuals walk for longer periods of time, walking performance is typically assessed using instrumented gait analyses over short walking distances. Additionally, some limited data suggest that alignment of the orthosis is an important consideration in facilitating efficient and stable gait. Yet, most clinically prescribed AFOs do not fully consider segment alignment. Methods of ‘tuning’ segmental kinematics using AFO-footwear combinations (AFO-FC) have been proposed. Therefore, we propose a prospective, randomized cross-over, comparative assessment trial with the following specific aims:

(1) to investigate how continuous walking affects the gait of persons with hemiplegia following stroke when walking without AFOs;

(2) to evaluate how well a clinically prescribed AFO addresses impairments that occur during continuous walking; and

(3) to evaluate if a ‘tuned’ AFO-FC is more effective than the clinically prescribed AFO at diminishing walking impairments during continuous walking.

Assessment of continuous walking will more realistically represent the day-to-day function of persons with hemiplegia and contribute to a better understanding of the effect of AFO use in the community.

Study Design 

The study team will recruit from both the Jesse Brown VA Medical Center and Northwestern University 21 subjects with post-stroke hemiplegia who regularly use an AFO. Subjects must also have limited ankle motion into dorsiflexion with the knee extended and abnormal shank kinematics during barefoot walking to meet the requirements for an AFO-FC.

The study requires 5 visits over approximately 5 weeks. At the first visit, an impression and measurements will be taken of the subject’s limb so that an AFO-FC may be fabricated. A second visit will allow fitting and ‘tuning’ of the AFO-FC. ‘Tuning’ of the AFO will take place with guidance from the Jesse Brown VA Medical Center Motion Analysis Research Laboratory, to ensure that the desired sagittal plane moments are created at the knee and hip. The subject will then be allowed three weeks of accommodation time. for the first two weeks of the accommodation period, the AFO-FC will be worn exclusively, with the subject asked to wear the AFO-FC “as much as possible.” During the last week of the accommodation period, the subject will be asked to wear alternately on a daily basis the AFO-FC and their clinically prescribed AFO. During the third, fourth and fifth visits, gait and energy data will be recorded in random order for each condition (no AFO, clinically prescribed AFO and AFO-FC) during continuous walking. These three visits will take place within a week and at the same time of day. 

 Subject Participation Timeline

References 

  1. Owen E. A clinical algorithm for the design and tuning of ankle-foot orthosis footwear combinations (AFOFCs) based on shank kinematics. Gait Posture. 2005;22S:36–37.

    2. Owen E. Proposed clinical algorithm for deciding the sagittal angle of the ankle in an ankle-foot orthosis footwear combination. Gait Posture. 2005;22S:38–39.

    3. Owen E. The importance of being earnest about shank and thigh kinematics especially when using ankle-foot orthoses. Prosthet Orthot Int. 2010;34(3):254-269. 

Related Publications

Umbrell C (2018) Principal Investigator: Improving Poststroke Mobility. O&P Almanac, April 2019, p.40-43. https://www.aopanet.org/publications/op-almanac-magazine/