March 2016

Ankle instability rehab emphasizes individuality

3Ankle-iStock64994205Research presented at the most recent International Ankle Symposium indicates that rehabilitation for chronic ankle instability is evolving from a one-size-fits-all approach to an increased focus on matching specific interventions to the patients who are most likely to benefit.

By Lori Roniger

The future of rehabilitation interventions for chronic ankle instability (CAI) could include combining treatments and personalizing rehab programs for individual patients and their specific deficits, according to new research presented at the 6th International Ankle Symposium in Dublin, Ireland.

“I think the key to successful rehab in people with chronic ankle instability is matching the treatment to the individual patient, not having a protocol applied to all patients,” said Jay Hertel, PhD, ATC, the Joe H. Gieck professor of sports medicine and codirector of the exercise and sports injury lab at the University of Virginia in Charlottesville. “Matching up the impairments identified in the evaluation should lead to the treatment they get.”

Hertel gave a keynote lecture on treatment strategies for CAI at the October 2015 symposium and emphasized in a phone interview after the event that, while CAI is multifactorial in nature, this doesn’t mean every patient is influenced by all the possible factors. In particular, he said, it is important to address those that contribute to a patient’s specific limitations, such as range of motion, mobility, strength, balance, or more functional issues involving gait or cutting and landing in athletes.

“We need to be treating everyone as an individual,” said Erik Wikstrom, PhD, assistant professor of sports medicine at the University of North Carolina at Chapel Hill, whose research on CAI rehab was presented at the conference.

A growing body of research suggests that ankle instability threatens quality of life and leads to decreased activity levels, which could have long-term implications.

Performing a baseline assessment of each patient and his or her impairments is particularly important in patients with CAI as that population is more heterogeneous than others, Wikstrom said.

Matching the treatment to the patient

Patrick McKeon, PhD, ATC, FACSM, assistant professor of exercise and sports sciences at Ithaca College in New York, has been working with Wikstrom and other researchers to determine which CAI patients will benefit most from specific interventions that have already been shown to be effective for improving CAI. The result has been what the researchers call a sensory-targeted ankle rehabilitation strategies (STARS) treatment paradigm.1,2

Their research has examined plantar massage, ankle joint mobilization, or calf stretching in CAI patients, and the effect on outcomes such as postural control, ankle joint range of motion, and self-assessed function.1

“All of those interventions improved more or less all of those outcomes,” Wikstrom said.

They found that response to treatment varied for each intervention—some individuals had large improvements while some had only small improvements—and they sought to determine if they could predict which interventions were best for which patients, starting with plantar massage and ankle joint mobilization.

They found that a baseline Foot and Ankle Ability Measure (FAAM) Sport score greater than 70.31% and a single-limb balance test improvement of at least 1.67 errors after one five-minute plantar massage treatment predicted which patients with CAI would improve their postural control after six such sessions over a two-week period, according to preliminary results presented at the ankle symposium.3

“Plantar massage really seems to be beneficial if there is a single-limb balance deficit,” Wikstrom said.

In another pilot study, CAI patients who were responsive to joint mobilization treatment had lower FAAM-ADL (activities of daily living) scores and higher anterior Star Excursion Balance Test scores prior to undergoing this intervention than those who did not respond.4 The treatment involved six sessions over two weeks; each session involved two two-minute sets of Maitland grade-II talocrural traction and four two-minute sets of Maitland grade-III anterior-to-posterior talocrural joint mobilization.

Mix and match

McKeon, who has both research and clinical responsibilities at Ithaca College, said he enjoys seeing the clinical improvements associated with such interventions; ankle joint mobilization, for example, can help increase dorsiflexion and self-reported function. He has also been developing protocols that he hopes will be practical in the real world.

While randomized controlled trials conducted for STARS interventions used only one form of treatment on each patient, McKeon and colleagues are now studying a multimodal approach in which CAI patients receive five minutes of joint mobilization, five minutes of plantar massage, and five minutes of foot core work three times a week for two weeks.

“After that, I typically introduce some balance activities like standing on one leg and hopping on one leg,” he said.

“If we don’t specifically address the gait mechanics through rehab, we don’t actually change the gait patterns.”
— Jay Hertel, PhD, ATC

Another study5 presented at the International Ankle Symposium by Wikstrom and colleagues examined whether combining balance training with multimodal STARS treatment in CAI patients improved static postural control more than balance training alone. While this preliminary research did not find a significant difference in static postural control between the treatment groups, Wikstrom said the results, which were based on a relatively small group of 24 patients, suggest that combining the treatments could be effective. He hopes to study this combination treatment in a larger group of patients and determine if any variables can predict a positive response to this intervention.

Impairment-based model

Luke Donovan, PhD, ATC, an assistant professor of kinesiology at the University of Toledo in Ohio, presented research at the ankle symposium on an impairment-based approach to CAI rehab. In this model, patients are prescribed interventions to address specific impairments (such as sensory issues, decreased proprioception, or altered gait kinematics) starting at levels that are challenging for the individual, instead of giving everyone the same tasks.

A study of his that was epublished in March by the Journal of Athletic Training examines the effectiveness of a four-week rehabilitation program in which CAI patients performed exercises while wearing an ankle destabilization shoe or while on traditional unstable surfaces. The study’s protocol provided patients with challenging exercises throughout the study and focused on range of motion, strength, balance, and functional exercises. After patients were assessed, they started exercises at a level that was difficult for them.

“What we found more or less was that both groups progressed similarly with clinical measures,” Donovan said. “Everyone’s strength improved on average. I would say that these [ankle destabilization] devices are just as effective as unstable surfaces.”

At the symposium he presented the results of a second manuscript stemming from the same data that found impairment-based rehabilitation incorporating an ankle destabilization device was associated with improvements in dorsiflexion range of motion during the stance phase of gait—which is often limited in patients with CAI. The same protocol without the destabilization device had no effect on ankle dorsiflexion.6

He said the patients anecdotally enjoyed participating in the study and found the exercises challenging. These studies did not follow patients over the long term, although Donovan is replicating the study using different gait training devices and plans to follow patients over a longer period.

Hertel, one of the study’s authors, emphasized the importance of using specific interventions to address the altered gait patterns seen in CAI patients.

“If we don’t specifically address the gait mechanics through rehab, we don’t actually change the gait patterns,” he said. “Patients report feeling better but don’t see change in gait without doing specific gait interventions.”

Walk this way

Like other researchers, Donovan is trying to figure out how to best bring his research into the clinic. He’s been investigating the use of off-the-shelf video cameras to look for visual cues that differentiate between CAI patients and those who have never sprained their ankles, and the potential value of this information for CAI rehabilitation.

Donovan has also been studying the effects of an auditory biofeedback device, worn in a shoe, on gait in CAI patients. Recently published research reported that wearing the device was associated with decreased plantar pressure in the lateral column of the foot while walking on a treadmill.7 Since patients walk differently when using the device, he’d like to see if incorporating it into a rehab program causes lasting and long-term changes, such as altering gait, self-reported function, or incidence of giving way.

“There are pretty effective ways clinicians can measure strength, balance, or range of motion, but when it comes to functional movement patterns, it’s tough to assess,” Donovan said.

He also noted that CAI rehab studies typically have not reported long-term results.

Having a vision

A new area of research on which Wikstrom, McKeon, Hertel, and others are collaborating is examining whether CAI patients have an increased reliance on visual information. Some of them presented an abstract at the ankle symposium on their systematic review of the use of visual information in CAI patients compared with un­injured controls.8

Assessing 11 studies of single-limb stance under eyes-open and eyes-closed conditions in CAI patients, healthy individuals, or both, they found CAI patients rely more heavily on visual information during that task than controls. These sensory weighting differences suggest there may be a neurophysiological component to the balance deficits associated with CAI, Wikstrom said.

“We want to get a better understanding of the full spectrum of deficits associated with sensory reweighting,” he said.

The next step is to determine whether this outcome is treatable; however, he said, preliminary data from a few of his group’s ongoing investigations suggest existing interventions may not treat this issue. If existing interventions don’t adequately address the way patients use somatosensory versus visual information, that could explain why patients with CAI often continue to experience episodes of ankle sprain or giving way despite having gone through a full balance training protocol.

Changes in the brain

Phillip Gribble, PhD, ATC, FNATA, who spoke at the conference about CAI as the next injury epidemic, has been trying to document changes that CAI may cause in the brain and spinal cord pathways and how they may manifest into clinical functional deficits.

“There is a rise in understanding that chronic ankle instability creates some adaptations in the nervous system,” he said.

A study conducted by Gribble and colleagues published earlier this year found that fibularis longus corticospinal excitability was greater in controls than in CAI patients.9 He is currently using trans­cranial magnetic stimulation (TMS), which was used in the previous study, to detect differences in the corticospinal excitability of the peripheral muscles between CAI patients and ankle sprain copers (those who have a history of ankle sprain but don’t develop CAI).

“These results may lead to the development of novel rehab techniques,” he said.

Long-term consequences

Gribble noted that a growing body of research, some of it presented at the ankle symposium, has been finding that CAI threatens quality of life and leads to a decline in physical activity levels, which could have long-term implications.

A 2015 study by Hubbard-Turner et al found that physical activity levels were reduced in college students with CAI compared with healthy students,10 and another by Houston et al found that quality of life is reduced in individuals with CAI.11

“Something we all recognize that’s on the horizon is how to mitigate problems for CAI patients on this path toward long-term consequences and ultimately promote a physically active lifestyle in these patients,” Gribble said.

People are recognizing the long-term consequences of CAI and ankle instability, which include ankle osteoarthritis,12-15 as they have previously for anterior cruciate ligament (ACL) injuries.

“What we’re seeing with the ankle is clearly mirrored in the knee patient population,” he said.

Future research may investigate how interventions may help to turn CAI patients into copers.

“There has been, to my knowledge, no studies on how any interventions impact physical activity levels,” Wikstrom said. “That’s the next step.”

One challenge is that many patients with CAI come in for treatment only when they experience a recurrent ankle sprain or an episode of giving way and want treatment for acute symptoms, he noted.

“Generally, those get resolved and those patients disappear,” Wikstrom said.

These patients often don’t think they need rehab and don’t understand they may have residual impairments, he said.

“People don’t respect ankle injuries,” McKeon said.

Compliance and communication

McKeon talked about the importance of a maintenance program for CAI patients after they have undergone some form of rehabilitation, such as balance training.

“I think it’s really important for them to continue with those types of activities,” McKeon said. “If you don’t use it, you lose it.”

Such maintenance programs could include performing foot core exercises, foot massage, and trying to balance on one leg. McKeon also recommends that CAI patients get involved in an activity that promotes balance and dynamic movement, such as yoga, Pilates, tai chi, or hiking.

“There’s a reason that CAI is such a recalcitrant condition,” McKeon said. “I think compliance seems to be the biggest issue.”

He said he emphasizes to his CAI patients the outcomes and improvements they’re seeing while working with him. He likes to use self-reported functional scales, such as the FAAM, to show them where they have difficulties and where their abilities are improving through rehabilitation.

“Having the patients fill out the form initially is a good way for me to show them what their problems are and then to work through goal-setting with them to address those problems,” McKeon said. “I can then come back to how each intervention we include in their rehab ties back to the problem they reported. Then as we progress through rehabilitation, I have them revisit the FAAM and show them how they’re shifting their perception of difficulty based on the rehab. It definitely helps with the patients’ perception of why we’re doing what we’re doing.”

This approach also makes it easier to link changes in clinical outcomes—such as strength, range of motion, limb girth, and balance—to the subjective outcomes identified on the FAAM, he said.

Lori Roniger is a freelance writer based in San Francisco, CA.

REFERENCES
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