November 2014

Toe walking researchers revisit idiopathic label

Peds-Toes

Photo courtesy of Monica Foster Jacobs.

Two recent literature reviews underscore the lack of high-level evidence to support the various treatments available for idiopathic toe walking. But new research is starting to fill that void, and is also engendering new theories about factors that may contribute to the condition.

By Larry Hand

Hard evidence continues to elude researchers investigating the origins of and treatments for idiopathic toe walking (ITW) in children, but more are now focusing on identifying factors that may contribute to the condition—which many believe may not be idiopathic at all.

Looking into what children with ITW feel when they walk, for example, may point to an underlying cause. And studies that can compare children with ITW and children whose toe walking is diagnosis-specific may identify some commonalities.

At the American Orthotic & Prosthetic Association National Assembly in September, Mark Geil, PhD, director of the Center for Pediatric Locomotion Sciences at Georgia State University (GSU) in Atlanta, presented results of a trial he conducted involving 15 children with ITW and 15 typically developing children.

The children, who had a mean age of 6.7 years, a mean height of 1.2 meters, and a mean body mass index of 27.8 kg/m2, walked barefoot at a self-selected speed on three different surfaces: a rounded gravel surface, a standard pile carpet, and the smooth gait lab floor. Geil and GSU colleague Daniel Fanchiang, PhD, had the children walk 10 times on each surface and measured heel heights relative to each child. A heel marker height above baseline before 32% of the gait cycle may indicate early heel rise or toe contact.1

The ITW children walked with significantly lower heel height (indicating less toe walking) when walking on the gravel surface than on other surfaces. The analysis also showed identical gait patterns for the ITW and typically developing children when walking on the gravel surface, probably because the gravel provided more sensory input and stability, which may be a clue that could help identify a cause of ITW, according to Geil.

In the gait lab at Georgia State University, reflective markers are attached to anatomical landmarks on the foot and ankle to monitor ankle angle at initial contact and the presence of early heel rise. (Photo by Steve Thackston, courtesy of Georgia State University.)

In the gait lab at Georgia State University, reflective markers are attached to anatomical landmarks on the foot and ankle to monitor ankle angle at initial contact and the presence of early heel rise. (Photo by Steve Thackston, courtesy of Georgia State University.)

“The result we found wasn’t expected because the experiment we were doing was not designed to test the effectiveness of a terrain like that in this population,” he told LER. “But it was one of those happy, unexpected outcomes. What we really need to do is to design a study that, from the beginning, is focused on investigating the potential for walking barefoot on different terrains and effectiveness in controlling toe walking.”

He and his team are also considering expanding their study population base to include children with autism spectrum disorder who toe walk.

“Kids with autism have been excluded from our studies so far because we’ve been looking for individuals with no known diagnosis, something truly idiopathic. We recognize the sensory component there [in the autism population], too, and since we have what we think is an effective intervention, we could see how it works in that population, as well,” Geil said.

Vibration and vibration perception

Geil is seeking funding to expand his research into the sensory pathways involved in toe walking, with or without an underlying diagnosis.

“One of the focal areas we were really excited about is the potential for whole-body vibration as a different intervention that would address that sensory link to the need for toe walking in these kids,” he said.

But, in an article epublished in September by the Journal of Child Neurology,1 Geil and colleagues described unexpected results when they tested vibration as a therapy in children with ITW. They were seeking to expand on work done by Cylie M. Williams, PhD, and colleagues in Australia,2 who found that children who present with toe walking are more sensitive to vibrations than their typically developing peers.

“Children may be changing gait pattern to adjust to sensations they perceive during walking,” Geil said. “Our thought was, if we could flood that sensory pathway in these kids with standing for a minute on a whole-body vibration machine, it might affect their need to toe walk.”

In the study, 15 children with ITW and 15 typically developing children walked barefoot at self-selected speeds over a four-meter walkway before and after standing on a whole-body vibration machine for 60 seconds at 30 Hz, the minimum vibration frequency of the machine.

“We worked in a lot of protection for the kids in our protocol and the kids had plenty of opportunities to stop, but most of them actually really enjoyed standing on the machine barefoot,” Geil told LER.

The researchers analyzed velocity, cadence, step length, and step width, as well as the timing of heel rise, which previous research has shown to be an indicator of potential gait abnormalities.3

They found no significant differences between the two groups in gait patterns, and both groups experienced similar significant changes in vibration perception after the vibration intervention.

“The outcomes weren’t what we had hoped, so we’re looking to do a new round of a study like that,” Geil said. “The machine that we used was very limited. It was all we could afford. If we can figure out a proper dose, which involves both time on the machine and the frequency and amplitude at which the machine vibrates, then it’s three variables to sort out. It still has potential. It just needs a lot of tweaking at this point.”

Geil’s results appear to contrast with what Williams, now adjunct research fellow in the Department of Physiotherapy at Monash University in Victoria, Australia, and colleagues found.2 The Australians identified for the first time that otherwise healthy children with ITW exhibited motor and sensory deficits in a series of tests when compared with children who do not toe walk.

“There is a great deal of research being undertaken to better understand the challenges of sensory processing,” Williams told LER. “I think what has emerged from my body of research was that clinicians need to think more about the reason that the child may be toe walking, as current treatments have been showing limited success in long-term gait change. To better tailor treatment, sensory processing abilities should also be considered as part of the holistic approach to treating the child.”

Evidence for treatment

There is still much to be learned about ITW, Williams said.

“Given the family history, there may be a potential genetic link,” she said. “There may also be the possibility that ITW, in fact, may be a very mild form of cerebral palsy that is variable in presentation, or it may be associated with [having a] very high-functioning autistic spectrum disorder that is not able to be picked up on any current assessment. We also do not know the long-term impact of toe walking. While there are many family members who toe walk or toe walked as children who have an ITW gait, we do not know what is happening with their gait now.”

Williams and her colleagues assessed current treatments for ITW in a review published in the May/June 2014 issue of the Journal of the American Podiatric Medical Association (JAPMA).4 They gauged 21 published studies against levels of evidence. Briefly, they found some support in the literature for surgical interventions, serial casting, and botulinum toxin type A (BTX).

In the first of two case studies included along with the literature review in the JAPMA article, researchers placed a small arch filler in the footwear of a 7-year-old boy to increase the sensation of full foot contact. They reported a “notable” decrease in toe walking at three and six months when the child wore the footwear, with similar toe walking levels in and out of footwear. At 36 months of follow-up, the researchers reported minimal toe walking in or out of the footwear. They hypothesized that the improvement was related to an increase in plantar contact area created by the arch fillers.

In the second case study, a 7-year-old girl underwent weight-bearing serial casting and developed an allergy to the casting materials. She then received night splints and underwent an exercise regimen of heel raises on a small board. She did heel-only walking exercises with the foot dorsiflexed, which resulted in minimal improvement. Researchers injected BTX into the medial and lateral heads of the gastrocnemius muscle and casted her for seven days using a different material.

Then, researchers fitted a full-length carbon-fiber custom orthotic device with rearfoot control and instructed her to wear it as much as possible. Three years after she initially presented, she was not toe walking and she was wearing normal athletic shoes. Later, however, they observed that, though overall toe walking had been reduced, residual equinus persisted.

“There is still much to be understood about idiopathic toe walking and its relationship to sensory processing difficulties,” Williams said. “I believe this condition [ITW] is complex and the group of children presenting with this gait type is not homogenous. This makes it extremely difficult to tailor treatment and to understand the origin of the gait. There is currently no literature supporting or disproving that all children with ITW have sensory processing difficulties, only enough evidence to prompt clinicians that sensory processing abilities should be considered if providing treatment.”

Better with BTX?

Although BTX use in the child’s case described above was associated with an apparent benefit, the effectiveness of BTX in other studies has been mixed.

Pähr Engström, MD, and colleagues at the Karolinska Institute in Stockholm, Sweden, found in a randomized trial5 published in 2013 that adding BTX injections prior to cast treatment for ITW is not associated with better outcomes than cast-only treatment. In a trial published in 2010,6 the same group found that a single BTX injection in combination with an exercise program may improve walking pattern in children with ITW, but only occasionally led to cessation of toe walking.

Their later study included children evaluated at their clinic for ITW between 2005 and 2010. They randomized 26 children to receive casting only for four weeks and 21 children to receive casting plus BTX (four injections in each calf, 12 units/kg body weight) one to two weeks prior to casting for four weeks. The researchers conducted gait analysis before treatment and at three and 12 months after cast removal, as the children walked barefoot at self-selected speeds. Parents’ perceptions were part of the study’s primary endpoints, Engström said.

“When you examine a ITW child in your clinic and ask them to show how they walk, they never walk as they normally do, as the child is aware his or her walk is being examined,” he said. “Normally our walking pattern is handled on spinal level and we ‘do not use our brain’ to walk. But when you concentrate or think about your walk, then the brain overrules your normal walking pattern.”

The researchers found no difference between the groups for any gait parameter. Parents rating their children’s performances during barefoot walking before and after treatment also found no difference between groups. However, both groups showed “a marked improvement in all of these parameters after their respective treatments, at both three and twelve months.”

“Our study did not show any additional benefit with BTX compared to only casts,” Engström told LER. “If BTX is to be used, someone needs to show in a prospective randomized study that BTX has any role in the treatment of ITW. Will repeated injections of BTX have a better effect? We have no knowledge about that at present and, therefore, we believe BTX should not be used in the treatment of ITW.”

Both Engström studies were cited in a September 2014 systematic review of ITW literature published in the Journal of Rehabilitative Medicine.7 In that review, Annette A.A. van Kuijik, MD, and colleagues at the Rehabilitation Centre Tolbrug in the Netherlands concluded that the sustainability of beneficial effects after physical therapy or casting appears to be short, although preliminary evidence exists for beneficial effects of serial casting and surgery on passive ankle dorsiflexion. Sustainable effects lasting more than a year occur only after surgery, they wrote.

Limitations of the literature

Much of the research into ITW treatments or causes is lacking basic information, however, according to Louis J. DeCaro, DPM, a pediatric specialist in Massachusetts and president of the American College of Foot and Ankle Pediatrics, who treats at least five toe walking patients a week.

“I don’t really believe that there is a good standard of measuring dorsiflexion accurately in subtalar neutral, so I think some of the results are skewed,” he said. “I think a lot of the literature is flawed because the most critical part in what I believe in treating toe walking is being able to assess what is causing it. I don’t really believe there really is idiopathic toe walking. There’s a reason for it all, including things such as vision, autism spectrum, or undiagnosed equinus.”

Orthotic management of ITW has not been studied very well, DeCaro said. In the JAPMA review, only three of the papers analyzed discussed orthotic management, and the highest level of evidence was a case series.8

“You have many people making many different kinds of orthotics, but I see in practice as well as in research articles that there’s a big deficit in the type of orthotic that a child gets. It’s not controlling enough. If you don’t control whatever position you cast or ‘Botox’ in, you’re going to get failing results,” he said. “We need studies that have consistency in measuring dorsiflexion, consistency in casting techniques, consistency in orthotic treatments following any sort of successful therapy. As well, there’s no talk of referring to optometrists anywhere. It’s a huge factor in all of this. I’ve seen kids get glasses and immediately they walk on their heels.”

And when vision isn’t an issue?

“Regardless of if I cast, do surgery, or use Botox, I make sure I put a kid in a proper orthotic, no matter what age, to inevitably control the toe walking,” DeCaro said.

But research momentum may be building in a positive way.

“Longitudinal studies are very difficult to conduct due to both time and funding, especially when it is a rather benign condition,” Williams of Australia told LER. “I am really glad, though, that through the research we have done, there have been a number of research groups being established all over the world looking to better understand why some kids walk on their toes.”

Past research has focused on treating the symptoms of ITW because the cause has been considered unknown, Georgia State’s Geil added.

“That’s part of the reason why we’ve shifted our focus to investigations that might be able to get at the cause,” he said. “Then I think we can do some real good.”

Larry Hand is a writer in Massachusetts.

REFERENCES
  1. Fanchiang HD, Geil M, Wu J, et al. The effects of vibration on the gait pattern and vibration perception threshold of children with idiopathic toe walking. J Child Neurol 2014 Sep 26. [Epub ahead of print]
  2. Williams CM, Tinley P, Curtin M, et al. Is idiopathic toe walking really idiopathic? The motor skills and sensory processing abilities associated with idiopathic toe walking gait. J Child Neurol 2013;29(1):71-78.
  3. Alvarez C, De Vera M, Beauchamp R, et al. Classification of idiopathic toe walking based on gait analysis: development and application of the ITW severity classification. Gait Posture 2007;26(3):428-435.
  4. Williams CM, Tinley P, Rawicki B. Idiopathic toe walking: Have we progressed in our knowledge of the causality and treatment of this gait type? J Am Podiatr Med Assoc 2014;104(3):253-262.
  5. Engstrӧm P, Bartonek Å, Tedroff K, et al. Botulinum toxin does not improve the results of cast treatment for idiopathic toe-walking. J Bone Joint Surg Am 2013;95(5):400-407.
  6. Engstrӧm P, Gutierrez-Farewik EM, Bartonek Å, et al. Does botulinum toxin A improve the walking pattern in children with idiopathic toe-walking? J Child Orthop 2010;4(4):301-308.
  7. van Kuijik AA, Kosters R, Vugts M, Geurts ACH. Treatment for idiopathic toe walking: A systematic review of the literature. J Rehab Med 2014;46(10):945-957.
  8. Pomarino D. Pyramideneinlagen nach Pomarino. Orthopӓdie Technik 2003;11:810-813.

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