Orthotics

In-Progress Projects

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.

Post-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:

to investigate how continuous walking affects the gait of persons with hemiplegia following stroke when walking without AFOs;
to evaluate how well a clinically prescribed AFO addresses impairments that occur during continuous walking; and
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.

References

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.
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.
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/

Completed Projects

An Investigation of Ankle Joints for Ankle Foot Orthoses (AFOs)

Principal Investigator: Steven Gard, PhD
Co-Investigators: Andrew Hansen, PhD, and Rebecca Stine, MS
Stefania Fatone, PhD, Project Director
Funded by: Veterans Administration Merit Review
Status: Completed

When pathologies such as hemiplegia are present, ankle-foot function is disrupted and an AFO may be worn to restore function. The function imparted by AFOs relies largely upon the degree of resistance provided to rotation about the ankle. There are a number of ankle joints and motion control devices currently available for use in thermoplastic AFOs, but functional evaluation of orthotic ankle components is limited. The purpose of this randomized cross-over study was to assess the effect of different ankle components on the gait of adults with post-stroke hemiplegia who wore articulated AFOs.

Method

Three articulated AFOs with full-length foot-plates were custom molded of 3/16" polypropylene from the same cast by a single orthotist (a heel height board was used to cast the ankle at 90°). (See figure.) Subjects wore each AFO for 2 weeks in random order: 90° plantarflexion stop/free dorsiflexion (AFO1); plantarflexion limiter/free dorsiflexion (AFO2); 90° plantarflexion stop/dorsiflexion assist (AFO3). All AFOs used Tamarack Flexure Joints (Becker Orthopedic, Troy, MI). A baseline shoes only condition (NoAFO) was also recorded using standardized footwear (New Balance #926). Durometer selection for the motion limiter (60, 70 or 90) and dorsiflexion assist joints (75 or 85) were based on clinical evaluation of participants.

Gait analyses were conducted using the Helen Hayes marker set with ankle markers secured to the AFO with the proximal joint screw so that the marker center was in line with the joint axis. The VA Chicago Motion Analysis Research Laboratory is equipped with an 8-camera digital real-time motion capture system (MAC, Santa Rosa, CA) and 6 force plates (AMTI, Watertown, MA) embedded in a 10m level walkway. OrthoTrak software (MAC) was used to calculate kinematic, kinetic and temporospatial data. A minimum of 3 trials were averaged for each subject walking at a normal freely selected speed. Non-parametric statistical analyses were conducted.

Results

Data were analyzed for 21 subjects, 9 males and 12 females (mean age: 54.0 Â± 7.7 years, mean mass: 81.7Â±18.8kg, mean height: 169.3Â±10.5cm). Mean time since stroke was 6.6Â±5.8 years (12 left, 9 right hemiplegia). Subjects were broken down into two groups depending on whether or not knee hyperextension was present during gait without an AFO. Temporospatial variables did not differ between groups, but peak knee moment during loading response was significantly different for all conditions; knee angle during loading response were significantly different for all but the AFO2 and AFO3 conditions; and ankle angle at mid swing and initial contact was significantly different for all but the AFO2 conditions. There was no difference between conditions with regards to the load transfer transient. Table 1 shows the results as median (interquartile range) for all subjects and for the group with knee hyperextension.

Conclusions

For all subjects, all AFO conditions significantly increased walking speed and step length on the involved side to the same extent compared to NoAFO. In general, all AFOs had a more substantial effect on gait in persons with hemiplegia who exhibited knee hyperextension when walking without an AFO. Dorsiflexion assist joints did not provide additional dorsiflexion during swing when compared to AFOs without dorsiflexion assist. Results suggest that a larger sample size is needed to detect post-hoc differences for peak knee angle during loading response and load transfer transients.

An Investigation of Foot Alignment and Support in Ankle Foot Orthoses (AFOs)

Principal Investigators: Steven Gard, PhD, and Dudley Childress, PhD
Project Director: Stefania Fatone, PhD
Co-Investigators: Andrew Hansen, PhD, and Rebecca Stine, MS, Northwestern University; Bryan Malas, CO, MHPE, Department of Orthotics, Children's Memorial Hospital
Funded by: Veterans Administration Office of Research and Development (R&D), Rehabilitation R&D Service, Merit Review Grant A26761
Status: Completed

The purpose of this study was to investigate the effect on gait of AFO ankle alignment and foot-plate length in people with hemiplegia following stroke.

Results

This project has been completed. The results of this project are presented in each of the following publications:

Fatone S, Gard S and Malas B. (in press) Effect of Ankle Foot Orthosis Alignment and Foot-Plate Length on Knee Kinematics and Kinetics in People with Hemiplegia. Archives of Physical Medicine and Rehabilitation, 90(5):810-818.
Fatone S and Hansen A. (2007) Effect of an Ankle Foot Orthosis on Roll-over Shape in Adults with Hemiplegia. Journal of Rehabilitation Research & Development, 44(1):11-20.
Fatone S, Gard S and Malas B. (2007) Effect of AFO Alignment on Plantar Pressures During Walking in Adults With Hemiplegia. 12th World Congress of the International Society for Prosthetics and Orthotics, July 29 to August 30, Vancouver, BC, Canada.
Fatone S, Gard S and Malas B. (2007) Effect of Ankle Foot Orthosis (AFO) foot plate length on plantar pressures in adults with hemiplegia. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists, March 21-24, San Francisco, California.

Related Publications

Fatone S. (2009) Functional Evaluation of Ankle Foot Orthoses in Adults with Post-Stroke Hemiplegia. Invited Speaker, ISPO Canada Symposium "Prosthetics and Orthotics Care for People with Diabetes," October 22-24, Toronto, Ontario, Canada.
Fatone S. (2008) Functional Evaluation of Ankle Foot Orthoses in Adults with Post-Stroke Hemiplegia. Invited Speaker, Current Clinical Concepts in Orthotic & Prosthetic Rehabilitation, sponsored by the VHA O&P Education Committee as an extension of the O&P Strategic Planning, VA Prosthetic and Clinical Logistics (Central Office), February 6-8, Long Beach, CA.
Fatone S and Hansen A. (2007) Effect of an Ankle Foot Orthosis on Roll-over Shape in Adults with Hemiplegia following Stroke. Invited Speaker, 16th Annual Visiting Professor Symposium, Motion Analysis Center, Children's Memorial Hospital, November 9, Chicago, IL.
Fatone S. (2007) Effect of Ankle Foot Orthosis Alignment and Foot-Plate Length on the Gait of Adults with Hemiplegia. Invited Speaker, American Academy of Orthotists and Prosthetists Midwest Chapter Fall Meeting, November 3, Hickory Hills, IL.
Fatone S. (2007) Functional Evaluation of Ankle Foot Orthoses in Adults with Post-Stroke Hemiplegia. Invited Speaker, Bio-Interest Group (BIG) seminar series, Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, October 15, Urbana-Champaign, IL.
Fatone S, Gard S and Malas B. (2007) Effect of AFO Alignment on Plantar Pressures During Walking in Adults With Hemiplegia. 12th World Congress of the International Society for Prosthetics and Orthotics, July 29 to August 30, Vancouver, BC, Canada.
Fatone S, Gard S and Malas B. (2007) Effect of Ankle Foot Orthosis (AFO) foot plate length on plantar pressures in adults with hemiplegia. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists, March 21-24, San Francisco, California.
Fatone S and Hansen A. (2006) Effect of Ankle Foot Orthosis on Roll-over Shape in People with Hemiplegia. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists, March 1-4, Chicago, Illinois. (Recipient, Howard R. Thranhardt Lecture Award).
Fatone, S, Hansen, AH, Gard, SA and Malas, BS. (2005) Effects on Gait of Ankle Alignment and Foot-Plate Length in Ankle Foot Orthoses (AFOs). American Academy of Orthotists and Prosthetists, Annual Meeting, March 16-19, Orlando, Florida.
Fatone S. (2005) AFO study draws to a close: An investigation of the effect on gait of ankle alignment and foot-plate length. Capabilities, 13(1):6-12. Northwestern University, Chicago, IL, USA.
Fatone S. (2004) Effects on Gait of Ankle Alignment and Foot-Plate Length in Ankle Foot Orthoses. Guest Speaker, American Prosthetics and Orthotics Inc. Fall Scientific Meeting, October 23, Des Moines, Iowa.
Fatone S, Hansen AH, Gard SA and Malas BS. (2004) The Effect of Ankle Foot Orthosis Alignment on the Knee During Gait in Post-Stroke Hemiplegia. International Society for Prosthetics and Orthotics, 11th World Congress, August 1-6, Wanchai, Hong Kong, China.
Fatone S, Hansen AH, Gard SA and Malas BS. (2004) An Investigation of Alignment and Support in Ankle Foot Orthoses (AFOs). Invited Speaker, American Academy of Orthotists and Prosthetists, Midwest Chapter Spring Meeting, June 3-5, Milwaukee, Wisconsin, USA.
Fatone S, Gard SA, Childress DS and Malas B. (2004) An Investigation of Foot Alignment and Support in Ankle Foot Orthoses (AFOs). Gait and Clinical Movement Analysis Society, 9th Annual Meeting, April 21-24, Lexington, Kentucky, USA.
Fatone S, Gard SA, Childress DS and Malas B. (2003) An Investigation of Foot Alignment and Support in Ankle Foot Orthoses (AFOs). Children's Memorial Hospital Visiting Professor Symposium, November 7, Chicago, Illinois, USA.
Fatone S, Gard SA, Childress DS and Malas B. (2003) An Investigation of Foot Alignment and Support in Ankle Foot Orthoses (AFOs). American Congress of Rehabilitation Medicine, October 23-26, Tucson, Arizona, USA. Archives of Physical Medicine and Rehabilitation, 84(10):A1-A12. and Neurorehabilitation and Neural Repair, 17(4).
Fatone S. (2003) Research Projects Place New Emphasis on Orthotics. Capabilities, 11(4):12-13. Northwestern University, Chicago, IL, USA.
Fatone S, Gard SA, Childress DS and Malas BS. (2002) An Investigation of Foot Alignment and Support in Ankle Foot Orthoses (AFOs). Third VA Rehabilitation Research and Development National Meeting, February 10-12, Arlington, Virginia, USA (poster).
Fatone S, Malas B and Gard S. (2001) NUPRL & RERP Launches New Orthotic Research. Capabilities, 10(4):1-3,9,11. Northwestern University, Chicago, IL, USA.

Development of a Low-Cost Dilatancy-Based System for Orthotic Fabrication

Principal Investigator: Yeongchi Wu, MD,
Co-Investigators: Steven A. Gard, PhD; John Michael, MEd, CPO/L
Research Orthotist: Christopher Robinson, MS, MBA, ATC, CPO/L, FAAOP
Research Assistant: Larissa (Conner) Sletto, CO
Consultant: Hector Casanova, CP/L
Funded by: National Institute on Disability and Rehabilitation Research (NIDRR) Field Initiated Grant Number H133G110266
Status: Completed

The purpose of this proposed development project is to create a dilatancy (vacuum-based) system that will enable low-cost and rapid fabrication of orthoses. Previously, we developed a dilatancy casting system (i.e., CIR Casting System) for prosthetic socket fabrication with funding from the NIDRR RERC on Improved Technology Access for Landmine Survivors (1998-2008). This system has been adapted for fabricating more than 3,000 prostheses in India and Thailand.

The project goal is to design and evaluate an orthotic dilatancy casting system for capturing the impression of a body part in order to fabricate a custom orthosis biomechanically individualized for the person with disability. This system would replace the conventional method of taking impressions using plaster bandages. The primary target population will be trained orthotists who provide services to individuals with disabilities.

The objectives of this project are to develop and evaluate orthotic dilatancy technologies during a three year project in four stages:

1) Design and Laboratory Testing Phase: Develop equipment and procedures; and conduct laboratory testing on positive plaster models. 2) Clinical Evaluation Phase: Conduct clinical evaluations of new orthotic fabrication system on research subjects. 3) Review and Demonstration Phase: Demonstrate new orthotic dilatancy fabrication systems to practicing orthotists and orthotics students to acquire feedback and suggestions for further refinement. 4) Knowledge Translation Phase: Prepare detailed technical manuals for each validated orthotic dilatancy fabrication system for knowledge translation and hold workshops to train orthotists.

The orthotic dilatancy fabrication system will be developed in different stages, initially establishing procedures for smaller, simpler orthosis designs and progressing to those that are larger and more complex in the functions they provide. Efforts will be focused on five different types of orthoses that are commonly prescribed and fitted by orthotists: Foot Orthosis, Ankle-Foot Orthosis, Knee Orthosis, Knee-Ankle-Foot Orthosis, and Spinal Orthosis.

Like the previous prosthetic dilatancy casting system that we developed, it is expected that the orthotic dilatancy system will result in significant reductions in time, cost and waste materials produced compared with conventional means. As an alternative to both plaster-based and CAD-CAM-based approaches, we believe that orthotic dilatancy methods will be attractive within both resource-limited and health-care-cost-containment environments worldwide.

The project is consistent with NIDRR's Long Range Plan for the development of new knowledge and methods that can be translated through education and training conferences, courses or workshops to integrate development and practice to serve individuals with disabilities.

Effect of Ankle Joint Misalignment on Calf Band Movement in Ankle-Foot Orthoses

Principal Investigator: Steven Gard, PhD
Co-Investigator: Andrew Hansen, PhD
Project Director:Stefania Fatone, PhD
Funded by: National Institute on Disability and Rehabilitation Research (NIDRR)
Status: Completed

Accurate alignment of anatomical and mechanical joint axes is one of the major biomechanical principles pertaining to articulated orthoses, yet knowledge of the potential effects of axis misalignment is limited. The purpose of this project was to model the effects of systematic linear (proximal-distal and anterior-posterior) misalignments of single axis mechanical ankle joints in an ankle-foot orthosis (AFO) in order to determine the degree and direction of calf band travel that would occur over a functional range of motion.

Method

Sagittal plane misalignments of the ankle joint centers of an AFO were simulated using a simple two-dimensional model (see figure; copied from Fatone and Hansen (2007), P&O International 31(1):76-87) for both a range of ankle angles and a typical able-bodied ankle kinematic curve for self-selected normal walking speed. The model assumed that no movement occurred between the foot and the foot-plate of the AFO.

Results

The model predicted that for anterior (positive horizontal) misalignments, dorsiflexion movements would cause the calf band to travel proximally (i.e., up the leg) and plantar flexion movements would cause the calf band to travel distally (i.e., down the leg). The opposite was predicted for posterior (negative horizontal) misalignments. Proximal (positive vertical) misalignments would cause only distal movements of the calf band while distal (negative vertical) misalignments would cause only proximal movements of the calf band. Anterior-posterior misalignments were found to have a much larger effect on the amount of calf band travel than proximal-distal misalignments.

Related Publications

Fatone S and Hansen A. (2007) Effect of Ankle Joint Misalignment on Calf Band Movement in Ankle-Foot Orthoses. Prosthetics Orthotics International, 31(1):76-87.
Fatone S and Hansen A. (2006) A Geometric Model to Predict the Effect of Ankle Joint Misalignment on Calf Band Movement in an Ankle Foot Orthosis. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists, March 1-4, Chicago, Illinois.

Functional Assistance Provided by Myoelectric Elbow-wrist-hand Orthoses (FAME)

Co-Principal Investigators: Stefania Fatone, PhD, BPO(Hons), and Elliot Roth, MD
Study Coordinator: Jessica Yohay
Occupational Therapist: Caitlin Doman, OTR
Funded by: Myomo Inc.
Status: Completed
Acknowledgement: This project is part of a multi-site study led by Stephen J. Page, PhD, The Ohio State University.

Of the 5.7 million stroke survivors living in the U.S., the majority exhibits significant weakness in one upper extremity. This devastating impairment undermines performance of valued activities and diminishes quality of life. While many promising upper extremity rehabilitative strategies have been developed, most are only efficacious in mildly impaired individuals. In contrast, survivors exhibiting moderate upper extremity impairment constitute a larger proportion of the stroke population, yet exhibit little to no active movement in their paretic wrists and fingers; and limited active proximal movements. These diminished movement capabilities hamper participation in therapies that emphasize repetitive task practice. Hence, device-oriented approaches have been explored to facilitate increased movement capability in moderately to severely impaired stroke survivors. For example, sophisticated robotic systems have been developed to evaluate and treat patients who have sustained strokes; but the cost and complexity of these systems, as well as their size, limit their applicability in the clinical and home environments. A device that is compact, relatively easy to use, capable of capturing the interest of the user, and easily integrated into valued activities could potentially meet this need.

MyoPro 2 Motion G Device

The MyoPro 2 Motion-G (Myomo Inc., Cambridge, MA, USA) is a custom-fabricated myoelectric upper limb orthosis. It uses surface electromyography (EMG) signals from affected muscle groups to provide powered proportional assistance for elbow flexion and extension and gross grasp motions via motors attached to the exterior of the orthosis. It functions by continuously monitoring the surface EMG signals of the user’s biceps and triceps muscles for elbow motion; and the forearm flexor and extensor muscle groups for grasp motion. These signals are filtered and processed to provide a desired joint torque proportional to the effort that is exerted by the user.

Objective

The primary study objective is to compare upper extremity movement while wearing 1) the MyoPro 2 Motion-G; 2) a resting hand splint; and 3) no device among stroke survivors with moderate upper extremity dysfunction. During the study, subjects will undergo a short period of general training in the operation of the two orthotic devices and be guided through a series of standard clinical outcome measures. The entire study will enroll 75 stroke subjects (16 at Northwestern University).

Specific Aims

Determine the impact of the MyoPro 2 Motion-G myoelectric brace on affected upper extremity movement using the upper extremity section of the Fugl-Meyer Scale.
Determine the impact of the MyoPro 2 Motion-G myoelectric brace on affected upper extremity outcomes using a battery of functional tasks and the Box and Block Test (B&B).

iGRAB: Innovative Glove for Rehabilitation and Assistance using Biomimicry

Principal Investigator: Anjal Sharma, PhD, Lynntech, Inc.
Northwestern University Principal Investigator: Stefania Fatone, PhD, BPO(Hons)
Co-Investigators: Rebecca Stine, MS (Jesse Brown VA Medical Center); Elliot Roth, MD (Northwestern University); Daniel Nagle, MD (Northwestern University)
Research Assistant: Vasanth Subramanian, MS
Funded by: Department of Defense (Phase II SBIR, Award W81XWH-16-C-0012)
Status: Completed

The aim of the iGRAB, Innovative Glove for Rehabilitation and Assistance using Biomimicry, is to provide assistance during rehabilitation and every day activities to hand function that has been impaired by injury. During this Phase II Small Business Innovation Research project, our collaborators at Lynntech Inc. will continue development of the iGRAB from proof-of-concept to working protoypes (Figure shows conceptual design of prototype). Efficacy of the device in assisting grasping activities in persons with impaired hand function must be demonstrated. Therefore, at NUPOC quantitative clinical evaluation of hand function with and without the iGRAB will be evaluated in persons with impaired hand function.

Study Design

We will conduct a before and after trial of subjects with hand impairments due to stroke and traumatic hand injury. In stroke patients, patient-reported hand function will be characterized using the ABILHAND measure of manual ability for adults with upper limb impairments. In hand trauma patients, patient-reported hand function will be characterized using the Disabilities of the Arm, Shoulder, and Hand (DASH). On both testing occasions, hand function will be assessed during execution of functional tasks, similar to prior evaluation of upper limb prosthesis users in our laboratory. The Action Research Arm Test (ARAT) typically assesses upper limb functioning using observational analysis and grading of four subtests: grasp, grip, pinch, and gross movement. For this study, kinematic hand data during ARAT grasp and grip subtests will be collected with our motion capture system using retro-reflective markers located on the hand and forearm. Grip pressure during the grip subtest will be assessed simultaneously with kinematics using the pliance pressure measurement system with sensors mounted on the objects to be manipulated, like the glass full of water that is poured into another glass. Satisfaction with device will be assessed in both groups using the Orthotic and Prosthetic Users’ Survey (OPUS) since it is suitable for both groups.

Project Goals

This project will allow demonstration of efficacy for persons similar to the intended military population with hand trauma as well as stroke subjects, especially among the Veteran population.
Recovery of hand function following stroke is particularly poor compared with recovery of mobility. Up to three quarters of post-stroke patients have difficulty with grasping, holding and manipulating objects 3-6 months after their stroke, compared to 83% of post-stroke patients who are able to relearn walking.
Following acute rehabilitation, patients with hand trauma may be left with scarring, decreased range of motion, sensory deficits, decreased strength and conditioning, and functional deficits.
Evidence of iGRAB’s potential utility in helping patients from both populations regain hand function will greatly strengthen the likelihood of eventual commercial transition and acceptance of iGRAB for military, Veteran and civilian patient rehabilitation and assistance.

Improving Lower Extremity Orthotic Management of Children with Cerebral Palsy

Co-Investigators: Larissa Pavone, MD**; Deborah Gaebler-Spira, MD**; Donald McGovern, CPO, FAAOP**; Steven Makovitch, MD**
Project Director: Stefania Fatone, PhD, BPO(Hons)
Funded by: Orthotics and Prosthetics Education and Research Foundation (OPERF)
Status: Completed

**Shirley Ryan AbilityLab

Cerebral Palsy (CP) is the most common cause of motor disability in childhood and each child with CP has unique motor control issues that affect posture, standing balance, and gait. In conjunction with other medical, surgical, and therapeutic interventions, orthoses play an important role in the physical management of children with CP. For ambulant children with CP, evidence from gait laboratory studies suggest that ankle foot orthoses (AFOs) that prevent plantar flexion can improve temporospatial parameters of gait and ankle kinematics. More limited evidence exists for the indirect effects of AFOs on knee and hip kinematics and kinetics, with some suggestion that these effects can be optimized by 'tuning' solid AFOs and footwear. 'Tuning' focuses on manipulating segment kinematics, in particular shank (i.e., tibial) kinematics, to improve the relationship of the vertical ground reaction force (GRF) vector to the knee and hip during stance. However, most studies do not report systematically fine-tuning orthosis alignment or footwear when evaluating standing and walking in CP.

An approach to tuning of AFOs and footwear has been recently characterized and dubbed the Ankle Foot Orthosis-Footwear Combination (AFO-FC). The tuned AFO-FC consists of a rigid, non-articulated AFO in which Ankle Angle (AA) and Shank-to-Vertical Angle (SVA) are considered separately (see picture). AA refers to the angle of the ankle in the AFO and is based on measurements of muscle length, while SVA refers to the ankle of the shank/tibia with respect to vertical during standing and walking. Modified footwear is used in addition to wedges under the heel of the AFO and/or shoe to tune the SVA. Ideally a video vector visualization system is used to help determine optimal tuning of the AFO-FC.

Specific Aims

The specific aims of this study are to demonstrate that AFO-FCs improve knee and hip kinematics and kinetics during walking to a greater extent than 'conventional' AFOs, leading to improved balance, step length, walking speed, and self-reported function, and that these improvements increase with time. For the purpose of this study, 'conventional' AFOs are any design of orthosis that does not involve systematically fine-tuning orthosis alignment or footwear. We will use the Pediatric Balance Scale (PBS), the Pediatric Outcomes Data Collection Instrument (PODCI), the Orthotic and Prosthetic User Survey (OPUS), and instrumented gait analysis to compare AFO-FCs to conventional AFOs.

We will conduct a repeated measures pilot study of 3 children with spastic diplegic CP who have worn conventional AFOs for at least 6 months. Baseline clinical measures will include joint range of motion, muscle strength, muscle stiffness, selective motor control, and spasticity. A single orthotist will provide each subject with an AFO-FC fabricated and tuned per published algorithms. Tuning will be accomplished with assistance of ground reaction force visualization in the motion analysis lab. Gait analyses will be conducted with and without the conventional AFOs, and after one week and 4 months of AFO-FC wear.

Presentations

Fatone S, Gaebler-Spira D, McGovern D, Clancy T, Conaway P, Quigley M. (2015) Effect of two orthotic approaches on activity level, balance & satisfaction in children with cerebral palsy (CP). International Society of Prosthetics and Orthotics Congress, June 22-25, Lyon, France.
Fatone S, McGovern D, Makovitch S, Pavone L. (2013) Effect of Ankle-Foot Orthosis Footwear Combinations (AFO-FCs) on Gait Biomechanics and Function in Children with Cerebral Palsy. Rehabilitation Institute of Chicago Motion Analysis Center, 22nd Visiting Professor Day, November 8, Chicago, Illinois.
Fatone S, Stine R, McGovern D, Pavone L. (2014) Improving lower extremity orthotic management of children with Cerebral Palsy: AFO-FC case studies. 40th American Academy of Orthotists and Prosthetists Annual Meeting & Scientific Symposium, February 26-March 1, Chicago, Illinois.
Fatone S. (2014) Evaluating the effects of ankle-foot-orthosis footwear-combinations in children with cerebral palsy. Initiative ’93 Technische Orthopädie Symposium, March 3, Chicago, Illinois.
McGovern D, Fatone S. (2014) Evaluating the effects of ankle-foot-orthosis footwear-combinations (AFO-FCs) in children with Cerebral Palsy. Midwest Chapter of the American Academy of Orthotists and Prosthetists, One Day Fall Symposium, November 15; Hickory Hills, Illinois.

Investigation of Ankle Axis Misalignment in Ankle Foot Orthoses (AFOs) Using a Three-Dimensional Model

Principal Investigator: Stefania Fatone, PhD, BPO(Hons)
Co-Investigators: Kerice-Ahmun Tucker, BS; William Brett Johnson, PhD
Funded by: National Institute on Disability and Rehabilitation Research (NIDRR)
Status: Completed

Accurate alignment of anatomical and mechanical joint axes is one of the major biomechanical principles pertaining to articulated orthoses, yet knowledge of the potential effects of axis misalignment is limited. Congruency between anatomical and mechanical joint axes is considered important as misalignment results in undesirable forces (both shear and compressive) and moments, generated as the joints move through their ranges of motion. Inappropriate alignment of joint axes has consequences not only for the soft tissue at the interface, but also the integrity of the joints (mechanical and anatomical).

Joint axis misalignment consists of two components: linear (anterior-posterior and proximal-distal) and angular (transverse and coronal plane) misalignments. While the consequences of linear misalignments (i.e., 2-dimensional [2D] misalignments) at the ankle joint of an ankle foot orthosis (AFO) were modeled in a previous RERC-funded project, there has been more limited consideration for combined angular and linear misalignments at the ankle (i.e., 3-dimensional [3D] misalignments).

Current understanding of the effects of ankle axis misalignments in ankle foot orthoses is limited to linear misalignments. Since there is natural torsion of the tibia, rotational alignment of the ankle joints and the consequences of ankle axis misalignment in 3D needs to be considered.

Specific Objectives

Our objectives for this project include: (1) developing a 3D model to explore the effects of ankle axis misalignment; (2) using the model to systematically analyze the various combinations of ankle axis misalignments possible in an AFO and their effect on motion of the device relative to the limb and compressive displacements at the orthosis-user interface (which relate to pressure on the limb); and (3) compiling the completed program into an executable file that can be uploaded to the Web as an educational, interactive tool for use by orthotics students.

Progress to Date

A linear spring model was developed to represent the leg and AFO (Figure 1). The program can calculate and display all compressive displacements and corresponding pressure magnitudes for combinations of misalignments (Figure 2). The completed program, "AFO3D", has been compiled into an executable file, AFO 3D Installer (Windows 7 compatible) that can be downloaded from the project site, Simulation of Ankle Foot Orthotic Joint Misalignment.

Publications

Fatone S, Johnson WB, Kwak S (2016) Using a Three-Dimensional Model of the Ankle-Foot Orthosis to Explore the Effects of Combinations of Axis Misalignments. Prosthetics Orthotics International, 40(2)247-252. DOI: 10.1177/0309364614556839. http://poi.sagepub.com/content/early/2014/11/11/0309364614556839.
Fatone S, Johnson WB, Tucker K (2016) A 3D Model to Assess the Effect of Ankle Joint Axis Misalignments in Ankle-Foot Orthoses. Prosthetics Orthotics International, 40(2):240-246. DOI: 10.1177/0309364614543551. ISPO has designated this publication an open access article. It is available at: http://poi.sagepub.com/content/40/2/240.full

Presentations

Tucker K, Fatone S. (2013) Development of a three-dimensional simulation tool to investigate the effects of ankle foot orthotic joint misalignments. Midwest Chapter of the American Academy of Orthotists and Prosthetists, May 30-June 1, Lake Geneva, Wisconsin.
Fatone S, Tucker K. (2013) Development of a three-dimensional simulation tool to investigate the effects of ankle foot orthosis joint misalignments. Capabilities, 21(2):1-2.
Fatone S, Tucker K, Johnson WB, Kwak S. (2014) A 3D simulation tool to investigate the effects of ankle foot orthosis joint misalignments. 40th American Academy of Orthotists and Prosthetists Annual Meeting & Scientific Symposium, February 26-March 1, Chicago, Illinois.
Kwak S, Johnson WB, Fatone S. (2014) The Consequences of Ankle Foot Orthosis Joint Misalignment Using a 3D Model. National Conference on Undergraduate Research, April 3-5, Lexington, Kentucky.

Longitudinal Observation of Myoelectric Upper Limb Orthosis Use among Veterans with Upper Limb Impairment

Principal Investigator: Stefania Fatone, PhD, BPO(Hons)
Co-Investigators: Samuel Kesner, PhD (Site PI); Jonathon Naft, CPO, Myomo Inc.; Svetlana Pundik, MD (Site PI); Jessica McCabe, DPT; Peggy Skelly, PhD; Zhengyi Chen, PhD, MS; Ronald G. Reichers II, MD; Daniel Tran, MD, Louis Stokes Cleveland VA Medical Center
Collaborating Site: Cleveland FES Center
Status: Completed
Acknowledgment: The U.S. Army Medical Research Acquisition Activity, 820 Chandler Street, Fort Detrick MD 21702-5014 is the awarding and administering acquisition office. This work is supported by the Office of Secretary of Defense for Health Affairs, through the Orthotics and Prosthetics Outcomes Research Program, Orthotics Outcomes Research Award under Award No. W81XWH-16-1-0733. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the Department of Defense.

Traumatic Brain Injury (TBI) and stroke are a major challenges in the military and Veteran populations. Since 2000 to June 2015, 36,000 moderate and severe TBI incidents have occurred among US military and civilian casualties. In addition, arm and hand problems occur in about 17% of TBI patients and may limit ability to perform Activities of Daily Living (ADL).

To increase upper limb function, Myomo Inc. recently combined powered elbow with powered grasp to create the MyoPro Motion-G myoelectric elbow-wrist-hand orthosis. This commercially-available device is a non-invasive, powered device that is worn on a partially paralyzed arm to help initiate movement and enhance function. It is designed to be used by persons with various neurological problems, including TBI and stroke. When the user tries to bend their elbow or grasp objects, sensors in the orthosis detect the weak myoelectric signal, which activates the motor to move the arm/hand in the desired direction. The user is completely controlling their own arm and hand.

The MyoPro Motion-G is a relatively new orthosis, and clinicians and researchers know very little about how well it works to help improve arm and hand function in people with arm impairments, particularly those caused by TBI and stroke. This limits patient access to the orthosis. In addition, the benefits of adding powered grasp in conjunction with elbow function are unknown and have not been examined directly using patient-centric outcome measures. Combining device training with motor therapy and adding powered grasp may result in further improvements in arm function.

Purpose

The purpose of this research study is to document therapy and function outcomes over time in individuals who use an arm brace with powered elbow motion and hand grasp.

Objective

The objective of this single cohort study is to gather longitudinal outcomes in Veterans using the myoelectric upper limb orthosis with powered elbow and grasp in combination with motor learning-based therapy, documenting both patient-centric performance and patient-reported outcome measures. Longitudinal observation will document both the therapeutic effects and the functional outcomes of orthosis use.

Study Design

The study team recruited 15 individuals who had TBI or stroke and upper limb impairment. The study required 29 visits over 22 weeks and was divided into four parts: enrollment, orthotic fitting, therapy/training, and home use. Therapeutic and functional benefits were evaluated every 2-3 weeks over 18 weeks using a battery of outcome measures (Fugl-Meyer for upper limb, modified Ashworth scale, Chedoke Arm and Hand Activity Inventory, Orthotic and Prosthetic Users’ Survey satisfaction module, Craig Handicap Assessment and Reporting Technique).

Results

Thirteen subjects completed the study. Combined therapy of 27 hours in clinic resulted in impairment changes (assessed using the Fugl-Meyer Assessment) that were close to those reported with 150 hours of in-person motor learning-based therapy alone (Daly et al. Neurorehabil Neural Repair 2019; 33(7):1545968319846120.). While most outcomes improved during the in clinic phase and were maintained during the home phase, participation (assessed using the Craig Handicap Assessment and Reporting Technique) improved through both phases. Overall, it was feasible and safe to deliver the combination therapy. Combined therapy may allow high quality practice of movement in clinic and at home after stroke and TBI.

Publications

Pundik S, McCabe J, Kesner S, Skelly M, Fatone S. Use of a myoelectric upper limb orthosis for rehabilitation of the upper limb in traumatic brain injury: A case report. Journal of Rehabilitation and Assistive Technologies Engineering 2020; 7: 2055668320921067. https://journals.sagepub.com/doi/full/10.1177/2055668320921067

Related Information

Garrick, R. J. (2018, March 6). March Is Brain Injury Awareness Month.

Mediolateral Foot Placement and Related Biomechanical Impairments in Post-Stroke Individuals

Co-Principal Investigators: Steven A. Gard, PhD, and Stefania Fatone, PhD, BPO(Hons)
Student Investigator: Angelika N. Zissimopoulos, MS
Funded by: Orthotic and Prosthetic Education and Research Foundation (RFA OPERF-2010-FA-1; 2010 Recipient Angelika Zissimopoulos); Dr. John N. Nicholson Fellowship (2007-2012 Recipient Angelika Zissimopoulos); National Institute on Disability and Rehabilitation Research (grant H133E090009, 2008-2013)
Status: Completed

During locomotion, accurate mediolateral (ML) foot placement is important because it is closely related to movement of the body center of mass and is an effective mechanism for maintaining dynamic balance (i.e., forward progression without a fall) . The lower limb is aligned for each foot placement during the preceding swing phase of gait. Stroke is the leading cause of long term disability; and after a stroke, the swing phase is often characterized by drop foot and associated compensations to create toe clearance. Therefore, the phase of gait important for lower limb alignment and ML foot placement is characterized by abnormal positioning and movement.

Neither ML foot placement accuracy nor correlations between abnormal swing phase biomechanics and ML foot placement accuracy have been investigated in the post-stroke population. The first two aims of this study will address these gaps in current knowledge regarding post-stroke locomotion. Furthermore, the equinovarus position of the foot (and therefore the associated swing phase compensations) can be clinically addressed by prescribing an ankle-foot orthosis (AFO). It is currently unknown whether AFO related improvements in swing phase ankle and foot alignment have a positive effect on ML placement. This question is addressed by the last aim of this study. By investigating ML foot placement, a mechanism important for balance during locomotion, we will contribute new knowledge to the body of literature related to balance capabilities in post-stroke individuals.

Related Publications

Zissimopoulos A, Gard S, Stine R, Fatone S. Effects of an Ankle-Foot Orthosis on Foot Placement Post-Stroke: Balance Implications. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists (AAOP), March 21-24, Atlanta, GA, USA, 2012 (Podium Presentation).
Zissimopoulos A, Gard S, Stine R, Fatone S. Mediolateral Foot Placement during Post-Stroke Ambulation with and without an Ankle-Foot Orthosis. World Congress of the International Society for Prosthetics and Orthotics, February 4-7, Hyderabad, India, 2013 (Podium Presentation).
Zissimopoulos A, Fatone S, Stine R, Gard S. (2013) Effects of a Non-Rigid AFO on ML Foot Placement during Post-Stroke Locomotion, Gait and Clinical Movement Analysis Society, May 14-17, Cincinnati, OH, USA (Poster Presentation).
Zissimopoulos, Angelika (2013) An Investigation of Mediolateral Foot Placement during Post-Stroke Gait," PhD Dissertation, Biomedical Engineering, Northwestern University.
Zissimopoulos A, Fatone S and Gard S. (2014) The Effect of Ankle-Foot Orthoses on Self-reported Balance Confidence in Persons with Chronic Post-Stroke Hemiplegia. Prosthetics Orthotics International. 38(2)148-154. [Abstract]
Zissimopoulos A, Stine R, Fatone S, and Gard S. (2014) “Mediolateral foot placement ability during ambulation in individuals with chronic post-stroke hemiplegia.” Gait and Posture. DOI: 10.1016/j.gaitpost.2014.01.015. [Abstract]
Zissimopoulos A, Fatone S, Gard SA (2014) Effects of an Ankle-Foot Orthosis on Mediolateral Foot Placement Ability during Post-Stroke Gait. Prosthetics Orthotics International, May 30. pii: 0309364614534294. [Epub ahead of print].

Modeling the Effects of Hip Joint Stiffness on RGO-Assisted Gait

Principal Investigator: Steven Gard, PhD
Student Investigator: William Brett Johnson, PhD
Co-Investigator: Stefania Fatone, PhD
Funded by: National Institute on Disability Research and Rehabilitation (NIDRR)
Status: Completed

The Reciprocating Gait Orthosis (RGO) is an assistive device for persons with lower limb paralysis (LLP) that enables them to walk upright with crutches or a walker. However, walking with RGOs is slow and exhausting, which limits their use. Improving the efficiency of RGO-assisted gait could encourage persons with LLP to use their RGOs more often. The results of several studies indirectly suggest that increasing the hip joint stiffness of RGOs may improve their efficiency; however, further research is needed. One of the challenges of RGO research is subject recruitment because the population of RGO users is small and diverse, and recruiting a large, homogenous sample population requires time and resources. A model of RGO-assisted gait would allow for the initial testing and development of hypotheses without investing resources into subject recruitment. So, we designed a Lower Limb Paralysis Simulator (LLPS) that altered the gait of able-bodied persons such that it could model RGO-assisted gait. The goal of this project was to evaluate the LLPS's efficacy in modeling RGO-assisted gait while simultaneously investigating how changes in hip joint stiffness in different planes can improve RGO-assisted gait efficiency. We hypothesized that increasing hip joint stiffness in either plane would decrease arm loading. We also hypothesized that there was an optimal stiffness in the sagittal plane where oxygen cost would be minimized.

Methods

Five able-bodied persons were trained to ambulate with the LLPS, and a motion capture system and force plates were used to quantify their gait dynamics as they walked with the LLPS. The resulting data were compared to preexisting gait data from RGO users. Then, the subjects walked with the LLPS under eight conditions where the LLPS's hip joint stiffness was varied in the coronal and sagittal planes, and a motion capture system, force plates, and spirometer were used to measure their gait dynamics and energy expenditure. To verify the results of the LLPS model, two RGO users walked under three conditions where their hip joint stiffness was varied in the sagittal plane. An inclinometer, goniometer, spirometer, and instrumented crutches were used to quantify their gait and energy expenditure.

Results

The study showed that LLPS users naturally demonstrated distinguishing features of RGO-assisted gait, such as perpetual trunk flexion, intermittent hip flexion, and large forces borne through the arms. The study also showed that decreasing the hip joint stiffness in the coronal plane increased the LLPS users' oxygen cost by decreasing their walking speed and increasing the crutch force integral. LLPS users were also shown to have an optimal hip joint stiffness in the sagittal plane that minimized their oxygen cost by maximizing their walking speed. However, no changes in arm loading were detected in response to changes in hip joint stiffness in the sagittal plane. The RGO users responded to increased hip joint stiffness in the sagittal plane much like LLPS users. In fact, one of the subject's oxygen cost decreased 75% when the hip joint stiffness increased. In conclusion, the LLPS was found to be a useful tool in researching RGO-assisted gait, and increasing hip joint stiffness in the sagittal plane may help RGO users walk faster and more efficiently.

Pilot Investigation of the Functional Benefits of Stance Control Orthotic Knee Joints

Principal Investigator: Steven Gard, PhD
Student Investigator: Angelika Zissimopoulos, MS
Co-Investigators: Stefania Fatone, PhD, and Dudley Childress, PhD, Northwestern University
Martin Kacen, CO, Rehabilitation Institute of Chicago
Funded by: National Institute on Disability and Rehabilitation Research (NIDRR)
Status: Completed

Traditional orthotic knee joints utilized in knee-ankle-foot orthoses (KAFOs) are either locked or unlocked, depending upon the level of support required. Recently, new orthotic knee joints that allow stance phase control have become available. In the stance-control mode, these joints provide stance phase knee stability while allowing knee flexion during swing. Since there is minimal research examining these devices, the purpose of this study was to investigate the biomechanical and energetic effects of using a stance-control orthotic knee joint.

Method

To eliminate additional effects from pathologies, able-bodied subjects were fitted with a KAFO utilizing Horton's stance-control orthotic knee joint (SCOKJ®). (See figure.) Gait and energy expenditure data were collected with the SCOKJ® used in three operational modes: locked, unlocked, and auto (which blocks stance phase knee flexion but allows swing phase knee flexion). It was hypothesized that the auto mode gait data would more closely resemble the unlocked mode gait data than locked mode gait data, and that operating the KAFO with the SCOKJ® in the auto mode would yield lower oxygen cost compared to locked knee gait.

Results

Analyses of speed-matched kinematic and kinetic data from nine subjects revealed that orthotic side peak to peak stance phase knee flexion was significantly smaller for the locked mode compared to the unlocked and auto modes and was significantly smaller for the auto mode compared to the unlocked mode. Orthotic side peak to peak swing phase knee flexion was not significantly different between the auto and unlocked modes, but was significantly smaller for the locked mode than for both the unlocked and auto modes. These results were expected since the locked mode prevented knee flexion and the auto mode blocked stance phase knee flexion while allowing swing phase knee flexion. For the locked mode on the orthotic side, all subjects exhibited hip hiking and three subjects utilized circumduction as a means to provide toe clearance during swing phase. These compensatory mechanisms were eliminated in the auto mode for all subjects. Orthotic side knee flexion moments in early stance were smaller for the locked mode compared to the unlocked and auto modes, probably due to the reduced moment arm in the locked mode resulting from the loss of stance phase knee flexion. Additionally, the non-orthotic side hip moments in early stance were significantly larger than the orthotic side moments.

Finally, energy expenditure data indicated that the unlocked mode yielded the lowest oxygen cost while the oxygen costs for the auto and locked modes were not significantly different. It is possible that the auto mode does not reduce energy expenditure as hypothesized or that that the training period was not adequate enough (both in length and style of training) to allow subjects to become completely comfortable with the operation of the device. However, the benefits from improved kinematic and kinetic patterns may be more beneficial than a reduction in energy expenditure.

Through the use of an able-bodied model, this study illustrated the potential functional effects of using a stance-control orthotic knee joint compared to a traditional locked knee orthosis. Further research is required to verify if a patient population will produce similar results to those from this able-bodied model.

Related Publications

Boynton A. (2002) Reflections of the 2002 NIDRR Scholar: Applying Research in Clinical Practice. Capabilities, Autumn, 11(3):3-4. Northwestern University, Chicago, Illinois.
Zissimopoulos A, Fatone S, Gard S. (2005) Functional Benefits of Stance-Control Orthotic Knee Joints: Preliminary Data. Children's Memorial Hospital Visiting Professor Symposium, November 4, 2005, Chicago, IL.
Zissimopoulos Angelika Nikole. (2006) "The Biomechanical and Energetic Effects of a Stance-Control Orthotic Knee Joint," MS Thesis, Biomedical Engineering, Northwestern University.
Zissimopoulos A, Fatone S, Gard S. (2007) The Biomechanical and Energetic Effects of a Stance-Control Orthotic Knee Joint. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists, March 21-24, San Francisco, California.
Zissimopoulos A, Fatone S, Gard S. (2007) The Biomechanical and Energetic Effects of a Stance-Control Orthotic Knee Joint. Journal of Rehabilitation Research & Development, 44(4):503-514.
Zissimopoulos A, Fatone S, Gard S. (2007) Stance-Control Knee Ankle Foot Orthoses. Capabilities, 15(2):1-2. Northwestern University, Chicago, Illinois.
Zissimopoulos A, Fatone S and Gard SA (2010) Effects of a stance-control knee-ankle-foot orthosis on gait of able-bodied subjects (poster). World Congress of the International Society of Prosthetics and Orthotics, May 10-15, Leipzig, Germany.

Pilot Study: Effect of Two Orthotic Approaches to Ankle Motion Restriction on Activity Level, Balance and Patient Satisfaction in Children with Cerebral Palsy

Co-Investigators: Stefania Fatone, PhD; Donald McGovern, CPO, FAAOP**; Theresa Clancy, PT**
Deborah Gaebler-Spira, MD, Project Director**
Petra Conaway, PT, Study Coordinator**
Funded by: Ultraflex Systems
Status: In progress

**Shirley Ryan AbilityLab

Children with cerebral palsy often rely significantly on ankle foot orthoses (AFO's) for support while walking and tasks that require balance. The approach taken with orthotic management, specifically as it relates to the degree of ankle motion restriction, may impact activity level, balance, and satisfaction in children with cerebral palsy. We wish to assess the effect on activity level, balance, and patient satisfaction that the degree of ankle motion restriction provided by orthoses may have. This will be assessed by comparing complete restriction using a solid ankle foot orthosis-footwear combination (AFO-FC) versus allowing resisted, articulated motion using an Adjustable Dynamic Response AFO with supramalleolar orthosis (ADR AFO + SMO) (see picture). Both orthoses aim to improve biomechanical alignment in mid stance and restore/preserve rocker action for forward progression during walking. The AFO-FC approach accommodates limitations in muscle length within a solid AFO through alignment (choice of ankle angle). Roll-over or progression during stance is then accomplished through rockers on the shoe. The ADR AFO +SMO (with posting as needed for muscle limitations) uses variable plantar flexor and dorsiflexor resistance to influence shank biomechanics to maintain rockers for progression in stance with available motion preserved.

This study will use a single subject research design (A-A-B-C-B-C) that includes two baseline assessments one month apart wherein subjects will be assessed in their regular orthoses, followed by alternating month-long use of the two different ankle foot orthoses. Test orthoses (AFO-FC and ADR AFO + SMO) will be assigned in random order.We will recruit six children with cerebral palsy to participate in this study. Range of motion, muscle strength, muscle stiffness, spasticity, selective motor control, balance, walking function, satisfaction, and quality of life will be assessed at each time point in random order. Primary outcome measures include the Pediatric Balance Scale, the Orthotic and Prosthetic User Survey (OPUS) and Life-H. Between study visits, subjects' step activity will be monitored using a step activity monitor attached to the orthoses. To ensure that each orthosis is optimally tuned, we will use the motion analysis lab to visualize the ground reaction force vector in real time.

Pilot Study: Evaluation of Ankle Foot Orthoses (AFOs) Using Roll-over Shapes

Principal Investigator: Steven Gard, PhD
Co-Investigators: Dudley Childress, PhD; Andrew Hansen, PhD; and Rebecca Stine, MS, Northwestern University; Bryan Malas, CO, MHPE, Department of Orthotics, Children's Memorial Hospital
Project Director: Stefania Fatone, PhD, BPO(Hons)
Funded by: National Institute on Disability and Rehabilitation Research (NIDRR)
Status: Completed

The purpose of this case series was to explore the effects of clinically prescribed ankle-foot orthoses (AFOs) (i.e., the orthosis an individual is provided by their health care team for everyday use) on the ankle-foot roll-over shapes (ROS) of persons with various pathologies. We hypothesized that persons for whom AFOs had been prescribed would have an abnormal ROS and that AFOs would make the ROS similar to that of able-bodied persons. Gait data were recorded from eight adults with unilateral involvement: five subjects (one with a common peroneal nerve injury, one with a subchondral talar cyst, one with an incomplete spinal cord injury, one with hemiplegia due to stroke, and one with postpolio) wore posterior leaf spring AFOs (PLS-AFOs); two subjects (with hemiplegia due to stroke) wore articulated AFOs with a plantar flexion stop and free dorsiflexion; and one subject (with hemiplegia due to stroke) wore a solid AFO. Participants walked with and without their AFO at their freely selected walking speed. "Normal" reference data were recorded from 10 able-bodied subjects of similar age walking at similar speeds. As hypothesized, ROS-as characterized by arc length and arc radius-was abnormal for all subjects when walking without an AFO. However, the prescribed AFOs were only able to partially restore ROS. Arc lengths were closer to normal with the AFO when compared to without, but changes in arc radius were less consistent, with only three subjects having radii that were closer to normal when the AFO was worn. Overall, there were smaller changes in ROS arc length and radius when PLS-AFOs were worn compared with articulated AFOs, consistent with the fact that PLS-AFOs are typically prescribed for those with less severe pathologies. ROS arc length and radius increased in all subjects with stroke when AFOs were worn. The results of this case series suggest that although clinically prescribed AFOs tend to improve ROS compared with walking without an AFO, they do not completely normalize it. Further research is required to assess the relationship between gait dysfunction, AFO design, and ROS.

Results

This project has been completed. The results of this project are presented in the following publication:

Fatone S, Sorci E, Hansen A. (2009) Effects of Clinically Prescribed Ankle Foot Orthoses on Ankle-Foot Roll-Over Shapes: A Case Series. J Prosthet Orthot. 2009;21:196-203.

Related Publications

Sorci E, Fatone S, Hansen A, Gard S. (2007) Pilot Study Evaluating Ankle Foot Orthoses using Roll-over Shapes. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists, March 21-24, San Francisco, California. (Resident Poster).

Preliminary Quantitative Gait Analysis of Reciprocating Gait Orthosis (RGO) Users Simulation of Ankle Foot Orthotic Joint Misalignment (3D-AFO)

Principal Investigator: Steven Gard, PhD
Student Investigator: William Brett Johnson, MS
Co-Investigator: Stefania Fatone, PhD
Funded by: National Institute on Disability Research and Rehabilitation (NIDRR)
Status: Completed

This project studies the motions and associated energy consumption of Reciprocating Gait Orthosis (RGO) (see figure) users. The energy cost of walking in an RGO is very high, and we wish to find ways to reduce this cost. Very little has been published on the motion of RGO users; so, we quantified their gait in an attempt to identify the causes of the high energy cost.

Method

We measured the motion of five RGO users using a marker-based video motion capture system, the kinetics of their gait using force plates, their muscle activation patterns using electromyography, and their energy consumption using a COSMED portable spirometer. We used this data to calculate the net forces and moments acting on RGO users' hips and shoulders as well as the mechanical and metabolic energy used to walk with a RGO.

Results

We found that RGO users walk with a flexed trunk throughout the gait cycle. The RGO users flexed their trunks during periods of double support and extended their trunks during periods of single support. We also found that RGO users bore less than 40% of their body weight through their stance leg and more than 50% through their arms during portions of the single support phase. Bearing weight through the arms may be a source of high energy expenditure. We theorize that the flexed trunk posture encourages weight bearing through the arms during single support. With a flexed trunk, forces borne through the arms were shown to encourage trunk extension while forces borne through the stance leg encouraged trunk flexion. Therefore, to achieve the trunk extension observed during the single support phase, forces born through the arms increased and forces born through the stance leg decreased.

We also found that RGO users extended their swing hip at the beginning of swing. This motion is counterproductive to the forward advancement of the swing leg and may also be caused in part by the flexed trunk posture of RGO users and compliance within the RGO's reciprocal link. For the rest of the swing phase, however, we observed small net flexion moments at the hip. We also calculated that the rate of work done by the net moment at the hip during swing was less than the rate of work done by the net force acting at the hip. Since many of our subjects lacked active hip flexors we assumed that the moments at the hip were generated by the RGO's reciprocal link. The small moments, the low rate of work, and information from other studies concerning the reciprocal link lead us to conclude that the reciprocal link contributes little to advancing the leg forward during swing. The reciprocal link appears to be under utilized. If the link was used more during swing, then it may help reduce energy expenditure.

Finally, we observed poor conservation of mechanical energy at the RGO users' trunks. Poor mechanical energy conservation could be another source of high energy expenditure because more work may have to be done to maintain steady state walking. We theorize that this poor conservation is caused by a deceleration of the body during the latter half of single support, as indicated by posteriorly directed forces acting on the stance foot and walking aides of the RGO users.

Presentations

Johnson W, Fatone S, Gard S. (2009) Dynamic analyses of the gait of RGO users. Paper presented at: Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists; March 4-7, 2009; Atlanta, GA.
Johnson WB and Fatone S. (2006) Dynamic Analysis of an ARGO User. The Academy Today. American Academy of Orthotists and Prosthetists, Virginia, IL, USA.
Johnson WB and Gard S. (2006) Preliminary Findings from Quantitative Gait Analyses of RGO Users. BMES Annual Fall Meeting, Chicago, IL, October 11-14.
Johnson WB, Fatone S, Gard S. (2006) Preliminary Findings for a Pilot Study on the Mechanics of RGO Gait. 15th Annual Visiting Professor Symposium, Motion Analysis Center, Children's Memorial Hospital, November 10, Chicago, IL.
Johnson WB, Fatone S, Gard S. (2007) Preliminary Results for a Dynamic Analysis of RGO Users. Gait and Clinical Motion Analysis Society, April 11-14, Springfield, MA (poster).
Johnson WB, Fatone S, Gard S. (2010) Dynamics of Reciprocating Gait Orthosis (RGO) assisted gait. World Congress of the International Society for Prosthetics and Orthotics, May 10-15, Leipzig, Germany.
Johnson WB, Fatone S, Gard S. (2011) Investigating the effects of hip joint stiffness on RGO assisted gait with a lower limb paralysis simulator. Invited Speaker, Midwest Chapter of the American Academy of Orthotists and Prosthetists, June 3-4, Grand Geneva Resort, WI.
Johnson WB. (2007) Preliminary Findings for a Study of the Dynamics of RGO Gait. Capabilities, 15(2):3. Northwestern University, Chicago, IL.
Johnson WB. (2008) Dynamic Analysis of RGO Users. Paper presented at: Midwest Chapter Meeting of the American Academy of Orthotists and Prosthetists; June 27-28, Joliet, IL.

Publications

Johnson WB. (2008) Preliminary Quantitative Gait Analysis of Reciprocating Gait Orthosis (RGO) Users. MS Thesis, Biomedical Engineering, Northwestern University.
Johnson WB, Fatone S, Gard SA. (2009) Walking mechanics of persons who use reciprocating gait orthoses. J Rehabil Res Dev. 2009; 46(3):435-446.
Johnson WB, Fatone S, Gard SA (2011) Modeling the walking patterns of reciprocating gait orthosis users with a novel lower limb paralysis simulator. Conference Proceedings IEEE Engineering Medicine Biology and Society, Aug:7841-7844.
Johnson WB, Fatone S, Gard SA. (2013) Modeling the effects of sagittal-plane hip joint stiffness on Reciprocating Gait Orthosis Assisted gait. Journal of Rehabilitation Research and Development, 50(10):1449-1456.

Simulation of Ankle Foot Orthotic Joint Misalignment (3D-AFO)

Principal Investigator: Stefania Fatone, PhD, BPO(Hons)
Co-investigators: Kerice-Ahmun Tucker, BS, William Brett Johnson, PhD
Funded by: National Institute on Disability and Rehabilitation Research (NIDRR)
Status: Completed

During fabrication, an AFO’s joint axis must be aligned with the anatomical ankle axis to ensure that the AFO provides the desired function. However, sometimes, the two axes aren’t properly aligned, and the AFO fails to achieve the desired outcome. In an attempt to gain greater insight into the consequences of misalignment, a program called AFO3D was developed to simulate the likely result of both rotational and translational misalignments.

The following assumptions apply to the simulation:

The ideal AFO joint angle is the angle that minimizes the total potential energy of the system.
The AFO is rigid.
The AFO foot shell remains fixed relative to foot.
Ankle rotations take place about a single axis through the lateral and medial malleoli.
The AFO ankle joint is a single axis that rotates freely.
There is no slippage between the AFO and the leg.
The AFO does not alter the leg’s kinematics.

AFO3D Simulation of AFO Joint Misalignment Program

We have created an AFO3D-Installation Folder located outside this web page. The Folder contains: 1) the AFO3D Installer (an executable file); 2) the AFO 3D Installation Instructions; and 3) the AFO3D User's Manual. Everyone is welcome to access, view, download and use this program. Prior to leaving this web page, you may preview the AFO 3D Installation Instructions and the AFO 3D User's Manual or download from the off-site AFO 3D Installation Folder. Access the AFO 3D Installation Instructions for information and screen shots about the installation and extraction of the included MatLab compiler.

The program consists of two main windows: a command window where the simulation is setup and run, and a Plot Window where the results of the simulation are displayed. Open the AFO 3D-Installation Folder to access all resources.

Download the AFO3D_install program to your computer (Windows 7 compatible).
Double click the icon to open a black DOS prompt window and the program will download the MatLab Compiler.
Continue to follow the prompts for the MRTC installer.
After installation, click on the AFO3D icon to open and run the AFO3D app.

Publications

Fatone S, Johnson WB, Kwak S (2016) Using a Three-Dimensional Model of the Ankle-Foot Orthosis to Explore the Effects of Combinations of Axis Misalignments. Prosthetics Orthotics International, 40(2)247-252. DOI: 10.1177/0309364614556839. The online version of this article is available at: http://poi.sagepub.com/content/early/2014/11/11/0309364614556839.
Fatone S, Johnson WB, Tucker K (2016) A 3D Model to Assess the Effect of Ankle Joint Axis Misalignments in Ankle-Foot Orthoses. Prosthetics Orthotics International, 40(2):240-246. DOI: 10.1177/0309364614543551. The online version of this article is available at: http://poi.sagepub.com/content/early/2014/07/30/0309364614543551.

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