Foot orthoses provide viable treatment for back and hip pain

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Foot orthoses provide viable treatment for back and hip pain

They may change the mechanics of foot function to improve hip

extension and relieve symptoms.

By J. Light

http://www.biomech.com/current_full_article/?ArticleID=214

One of the most incapacitating injuries is chronic low back pain. The

problem is so severe that one-half of all Americans admit to having

back pain symptoms each year, and chronic low back pain is one of the

most common reasons for missed work, according to the American

Chiropractic Association. The ACA also estimates that as much as 80%

of the U.S. population will eventually experience a back problem. In

fact, chronic low back pain is so prevalent that Americans spend more

than $50 billion each year on its treatment, according to the ACA.

Recent research suggests that back pain may be closely linked to poor

or improper biomechanics. Many researchers, in fact, agree that

chronic low back pain may be significantly related to gait style, a

reason they are shifting their focus to the feet to treat hip and

back pain.

" Everyone who treats back pain knows it is a recurrent problem, " said

Dananberg, DPM, a renowned podiatrist based in Bedford, NH. In

the early 1980s, he became involved with computerized in-shoe

pressure testing. Dananberg's practice now specializes in the use of

in-shoe pressure analysis for the treatment of chronic

musculoskeletal pain.

" Why is back pain so recurrent? Because no one looks at the way you

walk, " he said. " We can cut the cost of treatment worldwide by

changing the way people walk, and we can do this with foot orthoses. "

Feet first

Using custom foot orthoses to change the mechanics of foot function

may improve hip extension and create prolonged relief of low back

pain symptoms, according to Dan­anberg. This is because the functional

limitation of hip extension during gait is one of the pathological

events that can cause or perpetuate chronic low back pain.

" If you had a headache and you took ibuprofen, but you kept hitting

yourself in the head with a hammer, you'd still get headaches, "

Dananberg said. " It's no different with back pain, which is caused by

functional limitation of hip extension during gait. This limitation

is in large part caused by faulty mechanics of the weight-bearing

foot in gait. "

To illustrate his theory, Dananberg used the example of an adult who

weighs 70 kg. Each lower-extremity limb accounts for approximately

15% of a person's total body weight. At toe-off, the large iliopsoas

muscles, which originate directly from the lower back, must fire to

assist in the development of the gait swing phase of motion. This

event is repeated, on average, about 2500 times per day. The weight

to be lifted equates to 26,250 kg per limb per day. If the origin of

these muscles fails to provide an adequately stable base from which

to lift these limbs, cumulative stress develops at the site of origin

and is felt directly as pain in the lower back.

Failing to extend the thigh from beneath the hip results in a loss of

preload mechanics, Dananberg said. The weight-bearing limb is for all

intents and purposes " stuck, " and the body is now assigned the task

of dragging this limb into motion. This overall process can either

cause or perpetuate chronic low back pain.

His take on orthotic function is also different from most

practitioners.

" The devices I prescribe have first-ray cutouts, kinetic wedges, or

reverse Morton extensions, all designed to prevent the development of

functional hallux limitus and, therefore, improve sagittal plane

function, " he said.

A cutout promotes sagittal plane function, thereby permitting

improved extension mechanics during gait. This leads to improvement

in the preswing mechanics and a more efficient swing phase, according

to Dananberg.

When the pelvis is rotated due to a pelvic upslip, a manual

adjustment in most cases can help resolve it. These manipulations

are generally performed by chiropractors, physical therapists,

osteopaths, and even some physicians who are appropriately trained.

Although performing manual adjustments to the pelvis can improve

pelvic tilts, Dananberg said that these patients often return again

for care with the same problem.

" When a pelvic tilt recurs on a regular basis, then it may relate to

some underlying leg-length difference that causes subtle gait

changes, which ultimately results in a repeat episode of the

misalignment, " he said.

A small underlying amount of leg-length difference exists among most

subjects who have chronic low back pain, according to Dananberg. The

amount of underlying discrepancy can range from 3 mm to 1 cm or even

more. Because normal foot function can accommodate some amount of

difference, fabricating a foot orthosis that does not take this into

account prevents accommodations from occurring. This can lead to

repeat episodes of dysfunction in the pelvis and subsequent pain. For

these reasons, Dananberg believes that the number of people who

should wear foot orthoses is far greater than those who actually wear

them.

" With the outcomes that I see, it would seem that prescribing foot

orthoses should be part of the treatment protocols for most back pain

treatment centers, " Dananberg said. " I just hope I live to see that

day. "

Foot pronation link

One common biomechanical abnormality is forefoot varus, which is

believed to incite excessive or prolonged pronation of the foot along

with internal rotation of the tibia and femur. A custom orthosis that

incorporates the construction of a medial forefoot post as part of

its design is intended to compensate for the structural abnormality

and reduce the incentive for abnormal pronation with internal

rotation. " The traditional podiatric view is that custom foot

orthoses should be designed in such a way as to compensate for

structural abnormalities of the foot that can induce excessive

pronation, " said Gross, MPT, ScD, a research associate with

the Boston University School of Medicine Clinical Epidemiology

Research and Training Unit and an assistant professor of physical

therapy at the Massachusetts General Hospital Institute of Health

Professions. " While there is some evidence that foot orthoses can

successfully limit the range of limb internal rotation during

walking, I know of no evidence that confirms the belief that a

forefoot post is necessary in order to achieve this effect. "

It has been suggested by some researchers that mechanical strain on

the hip can result from varus malalignment of the foot. Specifically,

forefoot varus malalignment may be associated with ipsilateral hip

pain or tenderness and total hip replacement in older adults,

according to a study that explored the cross-sectional relationship

between varus foot alignment and hip conditions in older adults,

Gross was the primary author of the study, published in Arthritis and

Rheumatism, in September 2007.

The Framingham osteoarthritis cohort study used a population-based

sample of 385 men and women (mean age 63.1 years). Researchers

measured forefoot and rearfoot frontal place alignment by taking

photographs of a nonweight-bearing view of both feet. Each foot

segment was categorized according to the distribution of forefoot and

rearfoot alignment among cases of ipsilateral hip pain, trochanter

tenderness, hip pain or tenderness, and total hip replacement (see

Table).

The relationship of foot alignment to these conditions was examined

using logistic regression and generalized estimating equations, which

were adjusted for age, body mass index, sex, and physical activity

level.

Results suggest that the mean standard deviation was 0.7° ± 5.5° for

rearfoot varus alignment and 9.9° ± 9.9° for forefoot varus

alignment. Subjects in the highest category of forefoot varus

alignment had 1.8 times the odds of having ipsilateral hip pain, 1.9

times the odds of having hip pain or tenderness, and 5.1 times the

odds of having undergone total hip replacement compared with those in

the lowest category. No significant associations were found between

rearfoot varus alignment and any hip conditions.

When the foot pronates excessively, the knee and hip alter their

position so that the femur internally rotates and the patella points

medial of the large toe. In addition, the knee goes into valgus

movement and the hip is adducted. Whether these changes in lower-limb

alignment and mechanics actually result in an increased risk for hip

trochanteric bursitis or lower lumbar pain is unclear, but many

patients with hip or lumbar diagnoses report feeling better when they

use a supportive foot orthosis, according to Gross. & #8194;

" My feeling is that we can increase our chances of success with an

orthotic prescription if we select only those patients whose hip or

back pain is clearly provoked by prolonged standing or walking,

because little benefit can be expected from a foot orthosis when the

pain is primarily provoked by sitting or lying, " Gross said. " I

accept that the current evidence does not support customization of an

orthosis as a first-line treatment. "

Gross believes that clinicians ought to concede that comparable

benefits might be frequently obtainable with a less expensive

prefabricated orthosis.

" Once we accept this, we ought to have an easier time accepting that

orthotic accessories, such as carefully & #8194;crafted forefoot posts and

first-ray cutouts, may be less essential than we once imagined, " he

said.

A great difference also exists between treatment of an existing hip

or lumbar problem with foot orthoses and prevention of a possible

future problem, Gross said.

" The latter is much harder and more expensive to study prospectively

than the former, and yet this is where orthoses are likely to have

their greatest impact, " he said. " Once local hip or lumbar

pathological changes have become substantial, local treatment may be

necessary regardless of what & #8194;distal biomechanical causes may have

contributed to the onset of these pathological changes initially. "

Playing through the pain

Among athletic individuals, sports activities often inflict a great

deal of pressure on the foot. Slight imbalances in the foot that are

not harmful or even detectable under usual circumstances may make an

individual more vulnerable to injury while playing sports. Foot

orthoses, however, can reduce fatigue and promote efficient muscle

function to enhance sport activity and performance by eliminating the

need for one's muscles to compensate for unnoticeable imbalances.

Wearing foot orthoses while playing golf may help reduce foot and

back pain and improve foot posture, according to a U.K. study in the

June 2007 issue of The Foot.

Thirty-two subjects at the University of Northampton (20 men, 12

women) participated in the randomized controlled trial. All

participants were over 30 years of age, with a mean average of 53

years for men and 55 for women. Each received one of three types of

orthoses fit to their regular golf shoes: the Vasyli Golf Orthaheel,

a prefabricated orthosis made of flexible EVA; a 3-mm thick Poron

insole that provides cushioning and shock absorbency; and a sham

insole with a Texon base and a 1-mm EVA cover that offered no

benefits. The subjects wore the orthoses over a three-month period

while playing golf. They completed the Foot Health Status

Questionnaire at the beginning and end of the study.

The researchers also assessed the subjects' Foot Posture Index score,

which determines whether a foot is supinated or pronated.Foot

function improved significantly more in golfers who wore the

Orthaheel than those who wore the other insoles (P = 0.053).

Furthermore, back pain was significantly reduced in the Poron group

(P = 0.007), according to results obtained using a visual analog

scale. FPI scores improved toward a more neutral foot position for

the Orthaheel and Poron groups and worsened toward greater pronation

in the sham group. The FHSQ scores also showed improvements for all

three groups, but no statistically significant differences were seen.

Gait analysis is the key

Decades of research on biomechanical evaluation and treatment of

foot, ankle, and lower-extremity conditions have been performed by

Bruce , DMP, a podiatrist from Valparaiso, IN, who is the

current vice president of the American Academy of Podiatric Sports

Medicine. Modifying gait to achieve symmetry between right- and left-

foot function is important when dealing with chronic hip and back

pain.

To that end, he relies on video and in-shoe pressure mapping

technology to assess gait motion by capturing pressure data in each

phase of motion, from heel contact to toe-off. His approach, which

focuses on force versus time curves, uses a three-box method

developed by Dananberg.

" We box out the heels, the forefoot, and the entire foot to detect

stoppages of motion that may indicate problems that need to be

addressed in an orthosis, " he said. " We can use differing

modifications that can help to eliminate these stoppages of motion

and allow the feet to gain symmetry. "

In his practice, specializes in custom foot orthosis

evaluation and in-house manufacture and computerized gait analysis

for chronic foot pain conditions, knee pain, hip pain and back pain.

He also provides diabetic foot evaluations to prevent or elimi­nate

foot ulcerations.

" Foot orthoses provide a viable alternative to surgery to treat hip

and back pain, " he said. " There are specific things to look for in a

patient's gait that can contribute to chronic hip and back pain and

what to do in those instances. "

Heidi Prather, an associate professor of physical medicine and

rehabilitation at the Washington University School of Medicine in St.

Louis, agrees that orthoses are a great alternative to other more

invasive treatments.

" Orthoses are helpful for supporting the arch of the foot, offloading

specific pressure points in the foot, and cushioning the heel, " she

said. " It's a noninvasive approach to improving biomechanics and

possibly pain, and the great part about it is that there is no age or

activity limit. "

Many researchers agree that foot orthoses can also increase stability

in an unstable joint, prevent a deformed foot from developing

additional problems, and improve overall quality of life.

" All you have to do is wear them to achieve your results, " said

. " No exercises or physical therapy is involved, and there is

no surgery from which to recover. " & #8194;