A Flexible AFO: Contradiction to Traditional Thought?

from O&P News - January 2018

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Research & Presentations

A Flexible AFO: Contradiction to Traditional Thought?

By Suzanne Guiffre, PT, EdD; Joseph Whiteside, CO, LO; and Cathy Bieber Parrott, PT

This article is a follow-up to research originally presented at AOPA’s Second World Congress and Centennial Celebration in Las Vegas in September 2017.

Introduction

Research shows ankle-foot orthoses (AFOs) improve walking ability, reduce energy expenditure, and improve selfconfidence in persons with neurologic conditions. 1 However, noted disadvantages of AFOs are orthotic size and weight, discomfort, safety issues, poor effectiveness, and the finding that dissatisfaction with AFOs has been found to be up to 75 percent, with lack of compliance ranging from 6 percent to 80 percent. 2 Some report AFOs are too restrictive to movement and skin problems are an issue. 3

Prior to this study, we tracked users of thermoplastic AFOs (n = 104). Fortyeight percent (50 clients) were unsatisfied

with their AFO. It was discovered that this lack of tolerance included 12 with a solid AFO, 30 with an articulating, 13 with a carbon fiber, and one with a double upright. Non-use did not seem related to the origin of the AFO (our clinic versus another), type of AFO, or diagnosis. The most common problem with non-use was postural instability resulting in limited walking ability. Other problems included weight, lack of comfort, decrease in dynamic balance, and inadequate ankle varus control. It was unacceptable that so many patients were dissatisfied or not using their AFO; thus, alternatives were pursued. There is previous research on silicone AFOs that showed increased comfort; however,

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Research & Presentations

these lack the required stiffness for gait. 4 The AFO desired needed to provide structural integrity with adequate stability, provide sensory input, improve function during walking, and be a positive experience for the client. Also needed was optimum shank-to-vertical inclination angle espoused by Owen 5 as essential for normalizing gait.

The result was a custom, total contact flexible AFO (patent pending) using EVA thermoplastic (Figure 1) in varying thicknesses to match patientspecific needs for functional assistance, sensory input, and structural stability. Initial response from clients included appreciation of the light weight and comfort of the soft flexible material. More active people who previously used an AFO describe increased ability to accommodate to uneven surfaces without losing balance but retaining the stability for controlled walking. We have now embarked on a study to evaluate the flexible AFO’s (FAFO’s) effectiveness for improving gait, balance, endurance, and client satisfaction.

Methods

Inclusion criteria included a physician-prescribed AFO for clients with stable neurologic conditions. Exclusion criteria include cognitive impairment, nonambulatory, or recent acute complication (wound or inflammation in the foot, etc.). Baseline measurements taken prior to receiving the FAFO included balance measured by the Berg Balance Scale (BBS), spatial and temporal gait parameters obtained from the GaitRite Walkway System, the Six- Minute Walk Test (6MWT) for aerobic endurance, and videotaped gait with Coach’s Eye. These same measurements were repeated after the client used the FAFO for two weeks and again after three months. In addition, wear-related questions from the Orthotic and Prosthetic Satisfaction Survey (OPUS) were administered at the two-week and three-month sessions.

Figure 1Flexible AFO with strapping

Results

Thirty-one adult clients have completed the study, and six more lack only three-month data. Recruitment is ongoing. While we continue to recruit to obtain a required sample size, we have run preliminary statistics. These findings and other early observational findings are promising. Twenty-eight subjects have completed the two-week data session (15 with FAFOs), and 22 subjects have completed the three-month data session. Attrition has been four subjects, from death (one), hospitalization (one), moving out of state (one), and discontinued use of the AFO (one). Twelve clients were previous AFO wearers, and 19 were new AFO wearers. Diagnoses of clients in the study is shown in Table 1.

Satisfaction with the FAFO measured by the OPUS shows the most satisfaction for fit, weight, and durability of the device. Patient satisfaction related to cosmetics and wear ability show less satisfaction. See Table 2 for all OPUS results. OPUS results of clients who had previously worn a typical thermoplastic AFO are analyzed separately, with noted higher satisfaction in several areas. For eight patients who previously used an AFO, satisfaction with the FAFO was 85 percent at two weeks and was maintained at three months. The average

wear time reported was 7.9 hours a day for six days a week. Those previous AFO wearers reported a longer wear time of 9 hours a day.

Statistical analysis on data collected so far was completed using the Wilcoxon Signed Rank test because assumptions for parametric t-test were not met. The alpha was set to 0.05 for testing differences among data collections (baseline, two-week, and three-month). Statistically significant results are presented in Table 3. Analysis will be repeated when required sample size is attained. Table 3 shows statistical results.

Velocity increased after two weeks with the new FAFO compared to without an AFO. Studies have shown that gait velocity increases with an AFO 6 so this finding is in line with other AFOs. However, there was no significant difference in velocity between the two-week and three-month points (p = 0.119). Forty-three percent were limited community ambulators 7 (or lower) at pre-AFO data session, but only 26 percent were at two weeks and 33 percent at the three-month data collection sessions.

The BBS showed a significant difference between pre-AFO and the twoweek point, with improved balance by an average of three points, which meets the Minimal Clinical Important Difference (MCID). 8 Between the twoweek and three-month points, scores improved slightly (one point) but were not statistically significant. Between pre-AFO and the three-month point, findings indicated gains were maintained (p = 0.009). A BBS of less than 45 indicates impaired balance and risk for fall. 9-11 The percent identified at risk for each group were as follows: pre-AFO, 39 percent; two-week point, 36 percent; and three-month point, 23 percent at risk for falls. Overall, 82 percent improved their balance scores with the FAFO.

The distance measured during the 6MWT showed improvement at each

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Research & Presentations

Table 1Diagnoses of clients

Diagnosis Requiring AFO

Number of

Subjects in Study

Stroke

Spine disorder 4Drop foot 3Multiple sclerosis 3Cerebral palsy 2Neuropathy 2Charcot-Marie-Tooth disease 2Myotonic dystrophy 2Guillian-Barre syndrome 1Amyotrophic lateral sclerosis (ALS) 1Myasthenia gravis 1Hereditary spastic paraplegia 1

Table 2OPUS results

Percentage That Agree or

Item on OPUS

Strongly Agree at Three Months

Fits Well 82%*

Weight manageable 77%*Comfortable 64%*Easy to don 50%*Looks good 45%Durable 82%*Clothes free of wear/tear 82%*No skin irritation 64%Pain-free to wear 64%* Items rated higher for previous AFO wearers.

Brain cyst 1

data point, but findings were not statistically significant. The average distance for each data time period were as follows: pre-AFO, 832 feet; two-week point, 866 feet; three-month point, 878 feet. Thirty-two percent of subjects improved on the 6MWT by at least 1 MCID (150 feet). 12,13 Again, the FAFO has results comparable to other studies that show an increase in the 6MWT with an AFO. 14,15

Table 3 Statistical findings

Statistical Analysis Wilcoxon Signed Rank Rest Results (alpha = 0.05)

Dependent Variable

Conclusion

Early data suggests the FAFO is able to provide benefits of increased walking velocity, improved balance, improved walking distance in six minutes, and good client satisfaction.

Significance

If with more subjects the statistical analysis confirms a positive effect on balance and walking ability, this FAFO

Statistical Result

will add to an orthotist’s options when prescribing an AFO. The FAFO is no more expensive to manufacture and so far has less orthotic service requirements than current AFOs. We expect the flexible nature of the material to result in reduced need for fit adjustments due to leg swelling or weight changes and with less skin irritation. These reductions should result in further decreased health-care costs and higher compliance.

Future studies should be conducted to determine if the FAFO is superior to current devices typically used and whether it provides greater reduced costs and improved patient quality of life. Additional gait parameters also need to be explored.

Velocity

Berg Balance Test

Six-Minute Walk Test

Clients walked faster with new FAFO at two-week point [WSR test significant (p = 0.000)].

Significant difference noted (p = 0.039) between pre- AFO and two-week point.

Distance improved at each data point, but not statistically significant.

Suzanne Guiffre, PT, EdD, is program director at Cleveland State University’s Doctor of Physical Therapy Program. Joseph Whiteside, CO, LO, is owner of Whiteside Orthotic and Prosthetic Group Inc., which is the clinic providing the FAFO for this study. Cathy Bieber Parrott, PT, is on the faculty at Youngstown State University’s Doctor of Physical Therapy Program.

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References 1. Slijper A, et al. Ambulatory Function and Perception of Confidence in Persons With Stroke With a Custom-Made Hinged Vs. a Standard Ankle Foot Orthosis. Rehabil Res Pract. 2012, Article ID 206495, 6 pages. 2. Bettoni E, et al. Neurological Patients and Their Lower-Limb Orthotics: Acceptance and Satisfaction. Prosthetics and Orthotics International. 2016; 40(2), 158-69. 3. Phillips M, Radford K, Wills A. Ankle-Foot Orthoses for People With Charcot-Marie-Tooth Disease—Views of Users and Orthotists on Important Aspects of Use. Disability and Rehabilitation: Assistive Technology. 2011; 6(6), 491-499. 4. Del Bianco J, et al. Comparison of Silicone Ankle-Foot Orthosis and Posterior Leaf-Spring Ankle-Foot Orthosis Using Gait Analysis in a Subject With Charcot-Marie-Tooth Disorder. Journal of Prosthetic & Orthotics. 2008; 20(4), 155-162. 5. Owen E. The Importance of Being Earnest About Shank and Thigh Kinematics. Prosthetics and Orthotics International. 2010; 234(3), 254–269.

6. Ferreira L, Neto H, Oliverira C, et al. Effect of Ankle-Foot Orthosis on Gait Velocity and Cadence of Stroke Patients: A Systematic Review. Journal of Physical Therapy Science [serial online]. n.d.:25(11):1503-1508. Accessed Aug. 23, 2017. 7. Perry J, Garrett M, Gronley JK, Mulroy SJ. Classification of Walking Handicap in the Stroke Population. Stroke, 1995;(6):982. 8. Gervasoni E, Jonsdottir J, Montesano A, Cattaneo D. Minimal Clinically Important Difference of the Berg Balance Scale in People With Multiple Sclerosis. Archives of Physical Medicine and Rehabilitation [serial online]. Feb. 1, 2017; 98(2):337-340. Accessed Aug. 23, 2017. 9. Berg KO, Wood-Dauphinee SL, et al. Measuring balance in the elderly: validation of an instrument. Can J Public Health. 1992; 83 suppl. 2: S7-11. 10. Kornetti D, Fritz S, Chiu Y, Light K, Velozo C. Rating Scale Analysis of the Berg Balance Scale. Archives of Physical Medicine and Rehabilitation. 2004;85:1128-1135. 11. Dogg an A, Mengüllüogg lu M, et al. Evaluation of the Effect of Ankle-Foot Orthosis Use

on Balance and Mobility in Hemiparetic Stroke Patients. Disability & Rehabilitation. 2011; 33(15- 16): 1433-1439. 12. Perera S, Mody S, Woodman R, Studenski S. Meaningful Change and Responsiveness in Common Physical Performance Measures in Older Adults. Journal of the American Geriatrics Society. 2006; 54(5):743-749. 13. Tang A, Eng J, Rand D. Relationship Between perceived and measured changes in walking after stroke. J Neurol phys ther, 2012; 36(3):115-21. 14. Nolan K, Savalia K, Lequerica A, Elovic E. Objective Assessment of Functional Ambulation in Adults With Hemiplegia Using Ankle-Foot Orthotics After Stroke. Physical Medicine and Rehabilitation [serial online]. Jan. 1, 2009;1:524-529. Accessed Aug. 25, 2017. 15. Sankaranarayan J, Gupta A, Khanna M, Taly A, Thennarasu K. Role of Ankle-Foot Orthosis in Improving Locomotion and Functional Recovery in Patients With Stroke: A Prospective Rehabilitation Study. Journal of Neurosciences in Rural Practice [serial online]. October 2016; 7(4):544-549. Accessed Aug. 25, 2017.

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