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Orthotic Assessment for Individuals With Postpolio Syndrome: A Classification System

Kelley, Carolyn PT, MS, NCS; DiBello, Thomas V. BS, CO, FAAOP

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JPO Journal of Prosthetics and Orthotics: October 2007 - Volume 19 - Issue 4 - p 109-113
doi: 10.1097/JPO.0b013e318157105f
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Technological advances have given individuals with postpolio syndrome (PPS) and orthotists more choices in orthotic design and fabrication to sufficiently support and assist weakened lower extremities (LEs) while walking, standing, and transferring. The most commonly seen advances in orthotic fabrication are the use of plastic, carbon fiber, aluminum, and titanium materials, and different kinds of ankle and knee joint components. Weight reduction of the orthosis will have a significant effect on the person’s energy expenditure and ability to move an already weakened limb.1–4 When Brehm et al.5 compared patients with PPS with age- and gender-matched healthy control subjects, they found those with PPS to have 28% slower gait velocity, 9% greater energy consumption, and 40% greater energy cost. Half of the patients with PPS used orthoses.5 Additionally, in a study reported by Kelley,6 male and female subjects, at all ages, with PPS were able to walk significantly less distances during a 6-minute walk test than normal values reported in the literature.

There are many challenges in recommending assistive devices, especially orthoses, to people with PPS, as this patient population has worked extremely hard to overcome their impairments and functional limitations. When other pathologies are not present, the person with PPS will present with muscle weakness, no spasticity, intact sensation, intact cognition, joints with hypermobility, hypomobility, or normal mobility, and an incredible ability to compensate. Many will see the recommendation of an orthosis as a failure or clear evidence that they have gotten worse. Their compliance in wearing an orthosis will depend on the soundness of the recommendation, fit and comfort, and its impact on daily function.3 Even when the polio survivor refuses to accept an orthosis, healthcare providers must inform him or her of the options, benefits, and costs, so that any decision that the patient makes will be an informed one. There are, unfortunately, few clear published guidelines to facilitate the healthcare provider’s decision making process in the area of orthoses, and none specific to patients with PPS.7 Therefore, the purpose of this classification system proposal is to provide clinical guidelines for the recommendation of orthoses for individuals with PPS. Generally, these patients will present to their physician or out-patient clinic because of concerns about pain, falling, new weakness, or fatigue.

CLASSIFICATION SYSTEM

An important consideration when recommending orthoses is the person’s previous orthosis use. The person may have worn unilateral or bilateral orthoses since the original onset of polio and has continued to wear one or both for decades. Conversely, the person may have never worn an orthosis because of insufficient residual weakness or lack of resources (educational, financial, and so on) in obtaining one. Also, the person may have worn an orthosis during the acute recovery phase of the polio and then discarded it because of the amount of strength gain, rebellion, or orthopedic surgery (arthrodesis or tendon transfers). There are polio survivors who have been quite adept with minimizing or camouflaging their weaknesses and problems. Some have denied their problems for a lengthy time period, and many never had an opportunity to grieve for their losses. There are also polio survivors who have coped and adapted well to their original loss of muscle strength and function and who may be coping well to the newer diagnosis of PPS.4,8

The domain of interest for this classification system will be orthotic recommendations for adults with PPS who are experiencing pain, falling, new muscle weakness, or excessive fatigue. Individuals who have other comorbidities, such as stroke or diabetic neuropathy, can be included in this classification system, but their clinical presentations will likely complicate the decision making process. Polio survivors with residual sequelae, without PPS, can also be included in this classification system.

Because of the complexity and diversity of polio survivors, this will be a multi-axial classification system. The first set of categories will be related to previous orthosis use: 1) no previous orthosis use, 2) previous orthosis use, but no current use, and 3) previous and current orthosis use. These categories are nonoverlapping and mutually exclusive, even if the polio survivor has very different clinical presentations of his or her two LEs.

Polio survivors with no previous orthosis use may present with very little residual weakness and have been able to compensate for or hide this weakness for many years. These patients may be very reluctant to accept bracing recommendations because of how successful they have been in masking their problems. There are also people who did not have either financial resources to obtain orthoses or access to knowledgeable healthcare providers from whom they could obtain orthoses.4

People who had used orthoses in the past but discarded them because of dramatic recovery in strength are very proud of their achievement in being able to “walk out of their braces.” Others that fall into the group of patients who discarded their orthoses, usually during adolescence or young adulthood, are those who discontinued their use because of vanity and wanting to wear “normal” shoes. Polio survivors who stopped wearing their orthoses because of these reasons will again be quite reluctant in resuming orthosis use. There are others, however, who had discarded their orthoses because of the relative success of tendon transfers, partial or full arthrodeses, or both.4

Polio survivors who have used orthoses since the original onset of polio are quite different in their outlook of orthoses. For many, their orthoses have become part of their body image. They will replace orthoses as needed, but they may be hesitant to try newer designs to lighten the weight, provide more control, or both.4

The next three categories of pain, falls or near falls, and increased weakness or fatigue are not mutually exclusive, as the polio survivor may present with one or several of these interdependent issues. However, the orthotist, therapist, and patient may determine that one category overrides the others in terms of how much it interferes with daily activities.

The second category to be discussed is that of pain. The pain may present in the joints of the affected LE because of abnormal stresses due to many years of compensations. It may also present in the affected muscles because of overuse associated with PPS. Pain can also occur in the less affected LE, again because of the years of compensation and overuse related to the inability to fully accept weight onto the weaker LE, adequately clear the weaker LE in swing, or both. The person with PPS can present with one or more pain issues, requiring astute examination and evaluation by the orthotist and therapist or possibly referral to the physician. Appropriate orthoses can be helpful in pain reduction by stabilizing one or more joints or restricting painful motion.1,4,9 Because pain is a signal of a problem in the body, any level or amount of pain that occurs or worsens while standing or walking needs to be assessed for possible intervention with an orthosis. Pain ratings can be taken before and after orthotic intervention to help the polio survivor understand how the orthosis can be effective in pain reduction. Self-report on a 0 to 10 scale or marking on a visual analogue scale can be useful for this purpose.

The third category is that of falls or near falls. The therapist must remember that the person with PPS will need to be screened for other medical problems that can contribute to falling, near falls, or loss of balance. These conditions include orthostatic hypotension, cardiac arrhythmias, vestibular dysfunction, and peripheral neuropathy. Accurate diagnosis of these possible comorbidities is essential, as orthoses will not reduce the risk of falling in several of the listed conditions. The patient may be falling or experiencing near falls due to stance-related issues, such as the knee buckling during weight acceptance. The patient may also be having difficulties in swing phase because of insufficient toe clearance causing stumbling.10 The polio survivor can have problems in both stance and swing phases, in one or both LEs.3,4 In a study of 233 polio survivors, 64% reported at least one fall within the previous year, 61% required medical attention, and 35% sustained at least one fracture due to falling.10 There are also patients who are wearing orthoses that continue to fall. These orthoses are inadequately controlling the weak limb or limbs, and assessment of appropriateness of a more supportive orthotic design, use of an upper extremity assistive device (crutches, walker, and so on), or motorized locomotion needs to occur.

The fourth category is for patients who have less specific complaints, such as increased muscle weakness, fatigue, or decreased walking endurance. In this instance, an orthosis may be prescribed to improve energy efficiency during ambulation.5,9,11–14 An endurance measure such as the 6-minute walk test can be used before and after orthotic intervention to determine whether the orthosis allowed the person to walk a longer distance. Again, an objective measure such as the 6-minute walk test distance can help to reinforce the benefits of the orthosis to the reluctant polio survivor. See Figure 1 for a schematic diagram of the domain and four categories.

Figure 1.
Figure 1.:
Schematic diagram of classification system used for orthotic decision making with individuals with postpolio syndrome.

PATIENT CASE EXAMPLE

A patient case will now be used to illustrate how this system can be used. N is a 50-year-old woman who caught polio at 11 months of age. She reported that the polio affected her right LE and arm. She wore a metal and leather ankle-foot orthosis (AFO) until the age of 6 years. She had an Achilles tendon lengthening procedure with a partial ankle fusion at the age of 13 years. She works 40 to 50 hours per week as a registered nurse in a busy public out-patient clinic. Other medical conditions include hypertension and osteoporosis. She presents to an out-patient polio clinic with complaints of frequent falls, severe right ankle pain, generalized muscle and joint pain, and severe fatigue.

Examination showed upper extremity and hand grip strength to be within normal limits. Her left LE also displayed strength of 5 out of 5 throughout. Her right LE was 3+ to 4 out of 5 throughout, with ankle strength testing compromised because of severely limited passive range of motion. No dorsiflexion passive range of motion is present on the right, with plantarflexion ranging from 0 to 15 degrees. Very limited inversion and eversion are present, too. Sensation is intact. N is tender to palpation at both sacroiliac joints and multiple trigger points in her neck, scapular, and back regions. She is not tender to palpation on any part of her foot, but she reports the pain to be “deep” in the anterior part of the ankle joint.

She is walking with a straight cane on the left for long distances, but does not use one at home or at work, although she is reporting being on her feet much of the day. She displays a wide base of support, decreased weight bearing onto the right LE, with quick and short step on the left. Right initial contact is foot flat with knee extended. She tends to keep the knee extended throughout right stance until terminal stance. Her pelvis rotates posteriorly and downwardly secondary to late heel off in terminal stance. No loss of balance is noted during gait analysis. Upon questioning, N was able to state that her right ankle pain was exacerbated each time her right leg was in trailing limb position in terminal stance, while stepping with the other leg. The therapist mechanically blocked her from accessing full dorsiflexion in weight bearing, and she reported that this significantly diminished her pain. She reports having sustained six to eight falls in the past year, with most occurring when fatigued. These falls were generally the result of her catching her right toes while stepping or her right knee buckling.

N will fall into category 1b (see figure attached) because she is not currently using an orthosis, but she had previously used one as a child. From there, she actually fits into category 2 (pain), 3 (falls), and 4 (new weakness and fatigue). However, her biggest concern was that of severe pain in her right ankle. Therapist was concerned that her joint fusion from more than 30 years ago was starting to deteriorate and that as she moved into her maximum dorsiflexed position, the bony surfaces were hitting inappropriately. In fact, N had been evaluated by an orthopedic surgeon who had recommended surgical excision of the bone spurs in this area. She would be classified into category 2a. The decision was to orthotically block this painful motion and prevent her from accessing her end range into dorsiflexion. Because plantarflexion did not seem to bother her, this motion would be permitted to allow smoother loading response. Because of her antalgic gait pattern, numerous other compensations were occurring that were likely contributing to her generalized pain (categories 2b and 2c) and fatigue (category 4).

N′s falls are also a concern, and she appears to be having stance and swing phase difficulties. Category 3b (stance-related) suggests a solid ankle or rear entry AFO, and the rear entry design will allow for the blocking of maximum dorsiflexion. A knee-ankle-foot orthosis may also be considered, but because she has a 3+/5 in her hip and knee extensors and intact sensation, she will likely be safe with a supportive AFO. When category 3c (swing-related) is applied, the dorsiflexion assist is recommended. Even though N′s rear entry articulating ankle AFO is blocking dorsiflexion, dorsiflexion can also be assisted in this design to allow her to pick up her toes more easily through the plantarflexion range that she has available. She denied any falls related to dizziness, orthostatic hypotension, and blood pressure medication side effects.

Category 4 (new weakness or fatigue) will not be considered with this patient case, as her bracing needs can be adequately met through categories 2 and 3. She should experience less fatigue if the orthosis increases her gait efficiency by preventing her pain, supporting her right lower leg and foot, and assisting her weak muscles.1,4

During N′s examination and evaluation, healthcare providers need to keep in mind her previous orthosis use and the number of years that have transpired with her successful ambulation with no orthosis (category 1b). As the determination of the type of orthosis appropriate for her needs is made, the orthotist and therapist must anticipate N′s likely reluctance, sadness, or refusal of the orthotic recommendation. The orthotist and therapist can inform N that the assessment can be thought of as an “information gathering time,” with no patient decisions needing to be made immediately. However, in N′s case, with a nonreversible surgery as one option, N elected to try the orthosis as a more conservative approach to manage her pain. If this were insufficient for her needs, she could always resort to the surgery at a later date.

DISCUSSION

This proposed classification system has been presented to facilitate healthcare providers in the clinical decision process that occurs during orthotic consideration and intervention of people with PPS. It is not intended to provide rigid guidelines that are to be followed at all times; patients with PPS, as well as many other patient populations, are very heterogeneous in their clinical presentations, and every possible patient scenario cannot be described or anticipated. However, the authors hope that this classification system can be helpful for clinicians who do or do not regularly work with individuals with PPS. This system can possibly be adapted for application to other patient populations, as well. It is also hoped that it can promote much needed research in the area of orthoses for evidence-based practice.

REFERENCES

1. DiBello T, Kelley C, Kaldis T, Vallbona C. Orthoses for persons with postpolio paralysis. In: Hsu JD, Michael JW, Fisk JR. Atlas of Orthoses and Assistive Devices. 4th ed. In press.
2. Hurmuzlu Y, Basdogan C, Stoianovici D. Kinematics and dynamic stability of the locomotion of post-polio patients. J Biomech Eng 1996;118:405–411.
3. Perry J, Mulroy SJ, Renwick SE. The relationship of lower extremity gait and strength parameters in patients with post-polio syndrome. Arch Phys Med Rehabil 1993;74:164–169.
4. Smith LK, Kelley C. The postpolio syndrome. In: Umphred DA. Neurological Rehabilitation. 4th ed. St. Louis, Missouri: Mosby;2001:576–594.
5. Brehm M, Nollet F, Harlaar J. Energy demands of walking in persons with postpoliomyelitis syndrome: relationship with muscle strength and reproducibility. Arch Phys Med Rehabil 2006;87:136–140.
6. Kelley C. Post-polio syndrome (monograph). American Physical Therapy Association Geriatrics Section; 2005.
7. Rancho Los Amigos National Rehabilitation Center Physical Therapy Department. Rancho ROADMAP (Recommendations for Orthotic Assessment, Decision-Making, and Prescription). Presented at the American Physical Therapy Association Combined Sections Meeting, San Diego, CA, 2006.
8. Bruno RL. The Polio Paradox: What You Need to Know. New York, New York: Warner Books; 2002.
9. Waring WP, Maynard F, Grady W, et al. Influence of appropriate lower extremity orthotic management on ambulation, pain, and fatigue in a postpolio population. Arch Phys Med Rehabil 1989;70:371–375.
10. Silver JK, Aiello DD. Polio survivors: falls and subsequent injuries. Am J Phys Med Rehabil 2002;81:567–570.
11. Bean J, Walsh A, Frontera W. Brace modification improves aerobic performance in Charcot-Marie-Tooth disease: a single subject design. Am J Phys Med Rehabil 2001;80:578–582.
12. Franceschini M, Massucci M, Ferrari L, et al. Effects of an ankle-foot orthosis on spatiotemporal parameters and energy cost of hemiparetic gait. Clin Rehabil 2003;17:368–372.
13. Danielsson A, Sunnerhagen KS. Energy expenditure in stroke subjects walking with a carbon composite ankle foot orthosis. J Rehabil Med 2004;36:165–168.
14. Mossberg KA, Linton KA, Friske K. Ankle-foot orthoses: effect on energy expenditure of gait in spastic diplegic children. Arch Phys Med Rehabil 1990;71:490–494.
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Keywords:

postpolio syndrome; lower extremity orthoses; classification system; pain reduction; fall reduction

© 2007 American Academy of Orthotists & Prosthetists