By Keith G. Rau, D.C., CCEP, Associate Professor, Life University
The use of orthotics is widely accepted and practiced in the chiropractic profession.
Orthotic use in athletic populations is also widely practiced by chiropractors,
podiatrists, physical therapists, athletic trainers and orthotists. There are
a variety of views on their usage, the examination and casting process and the
construction of the orthotics themselves. This article hopes to give insight
into the theory and practice of orthotics in a Sports Chiropractic setting.
Two recent articles about orthotics1 in The Chiropractic
Journal, written by its publisher, are convincing evidence of the widespread
support the use of orthotics has gained within the various camps in the profession.
The author states “In reality, anything that prevents, corrects or addresses
any component of the vertebral subluxation complex is rightfully within the
sphere of chiropractic and in complete accordance with chiropractic principles.”
It is hard to imagine a statement like that a few years ago.
Usage
Chiropractors have used a variety of types of orthotics to achieve varied purposes.
One could divide the purposes into two broad, overlapping categories. The first
is support of the kinetic chain. The second is the care of specific injuries/conditions.
As the Foot Goes, So Goes the Kinetic Chain!
Simply stated, any changes, whether biomechanical or neuromuscular, within the
lower kinetic chain, particularly the foot, may have far reaching effects. To
better understand this concept let’s review the gait cycle. The gait cycle
is commonly divided into the swing and stance phase (see
Figure 1). Upon heel strike the foot is supinated, immediately moves into
pronation, is in full pronation in mid-stance and returns to supination at toe-off.
In mid-stance the foot must pronate to achieve the shock absorption (pronation
is the body’s primary shock absorber) and allow the foot to conform to
the ground surface. At toe-off the foot should become a rigid lever to achieve
the goal of propulsion and insure a larger percentage of the forces by the limb
generate locomotion. (Think of the hard soles on cycling shoes, as opposed to
using running shoes, that allow the majority of the force generated to be transmitted
to the crank). The windlass effect, an involuntary action whereby dorsiflexion
of the great toe raises the medial longitudinal arch, plays a key role in the
supination during toe-off.
If the foot is pronated before the mid-stance phase, shock absorption is poor
and more force is transmitted up the kinetic chain. If the foot is rigid or
supinated during mid-stance the result is similar in that shock absorption is
poor and more force is transmitted throughout the kinetic chain.2
As the foot pronates the tibia and femur internally rotate, the pelvis rocks
and the lumbar spine rotates as well. The tibialis anterior, tibialis posterior
and psoas all eccentrically contract to decelerate this motion. With hyperpronation
these muscles are adversely affected. This may result in conditions commonly
seen in athletes such as medial arch pain, shin splints and low back pain. This
relationship explains why we always look at the lower kinetic chain in low back
pain cases and the spine in lower extremity conditions. The question is a “chicken
and egg” one. Does the subluxation, via decreased nerve supply, cause
the muscle failure or does the biomechanical stress of an injury to the kinetic
chain cause the subluxation?
The question is interesting but practically a simple process can help answer
it. If you suspect a lower kinetic chain problem is affecting the results of
your spinal adjustment(s), have the patient walk after adjusting them and then
recheck your indicators. Muscle testing is very helpful in this scenario as
it is an effective outcome tool. The doctor and patient can readily “feel”
the result as oppose to, for example, a leg check. If the indicators return
after walking there is a good chance the “cause” was not corrected.
When I first employed this process I was dismayed to see how often the indicators
returned. To complete the process, adjust the patient’s extremities and
recheck. You may have to adjust the spine again to complete the correction.
In practice, I routinely have patients walk, especially difficult cases, after
their adjustments and recheck key indicators to insure the correction is complete.
Specific Conditions—Hyperpronation
Recently during a presentation in class one of my student stated “hyperpronation
is the Devil!” While we all laughed, a review of the literature makes
the statement quite reasonable. Hyperpronation has been linked to hallux valgus
(bunions), plantar fascitis, shin splints, knee injuries, chondromalacia patella,
ACL tears, iliotibial band disorders, hip pain and low back pain to name a few
(see Figure 2). Hyperpronation
prohibits the foot from fulfilling its key role of shock absorption and increases
the internal rotation of the tibia and femur during the gait cycle. Because
the ACL lies at the axis of rotation of the tibia, increased internal rotation
increases the stress on the ligament and makes the athlete more susceptible
to injury. Orthotics are foundational to care for the athlete not just for symptomatic
presentation and prevention.3
Functional Hallux Limitus (FHL)
FHL is a very common condition of the foot that presents with decreased dorsiflexion
of the great toe. You can check this by first dorsiflexing the great toe. The
normal motion should be 70-90°. Second, firmly place your thumb behind the
first metatarsal head not allowing it to drop and again dorsiflex the great
toe. Less than the normal 35° in this loaded position is indicative of FHL.
It is typical to see an alteration of the normal callus pattern with little
or no callus under the first met head and large calluses under the 2nd -4th
met heads. FHL lessens the windlass effect and is worsened by hyperpronation.
The patient’s gait will be altered in typically patterns. The patient
may abduct the foot and “roll” off the inside of the foot to bypass
the restriction. This results in the typical “pinch” callus on the
medial aspect of the 1st met head. The patient may shorten their stride to accommodate
for the decrease motion or they may combine the two.
Orthotics are helpful by supporting the medial longitudinal arch and by making
a cut-out for the 1st met head. This allows the met head to drop during the
gait cycle. We joked at Life about our orthotics “gold standard.”
We made orthotics for a rugby player, posted them for a large forefoot varus
and had the lab make a FHL cut-out. We observed his gait before inserting the
orthotics and noted marked bilateral foot abduction. Immediately upon insertion
of the orthotics, the foot abduction was gone. He reported being able to run
longer with less effort when using the orthotics, than without them.
Other Conditions
In the past, heel spurs where thought to be the cause of heel pain and plantar
fascitis. Fortunately thinking has shifted to the idea that heel spurs are the
result of stress on the fascia not the cause. As Dr. Russell Erhardt used to
say, “show me a way to irritate the periosteum and I will show you a way
to grow bone.” Along with adjusting the lower extremities, orthotics can
be helpful by supporting the arches and cushioning the heel in patients with
plantar fascitis.
Another simple example of the benefits of orthotics is for patients with metatarsalgia.
Along with adjusting the fallen metatarsal heads, placing a metatarsal pad under
the metatarsal heads is very helpful. This condition is not serious but can
negatively impact the athlete’s performance.
Casting and Posting
The casting of orthotics varies depending on the practitioner and the company
they use. Some use a technique of obtaining sub-talar neutral (Root method)
and casting in a non-weight-bearing or semi-weight-bearing. Others use a simple
weight-bearing technique. Several companies now produce computerized devices
that use a sort of force plate to determine the orthotic’s design. The
arguments for each are lengthy and often become personal. Nevertheless, despite
the various camps, the goal remains to correct abnormal mechanics and support
the arches.
You remember from physics classes that force equals mass times acceleration
(F=ma) and acceleration equals distance over time (A=D/t). To reduce the force
applied to the foot we must decrease the acceleration. Any body that has tried
to lose weight knows how hard it is to decrease the mass! It appears that orthotics
decrease acceleration by increasing the time not decreasing the distance. The
orthotic material increases the time of pronation thereby decreasing the acceleration.
In the sub-talar neutral school of thought, the foot is examined and in overly
simplistic terms, the angle at which the forefoot and rearfoot hang from the
tibia is measured. The technique is taught in the CCEP modules on the lower
extremity. 4-6° of forefoot varus is considered normal. The rearfoot should
be at 0°, neither a varus nor valgus position. Dr Hearon suggests that one
must perform this exam on 100 pairs of feet to gain competency as there is a
great deal of art to the technique.
With this method the doctor can either instruct the lab to post the orthotic
to the exam findings or to the cast. Posting done to conform to the cast is
called intrinsic. Extrinsic posting is the adding of material externally to
the orthotic to meet the varus or valgus needs of the patient. It is my experience
that many elite athletes have a large degree of forefoot varus. With overtraining
or injury, their body breaks down, can no longer accommodate, and symptoms develop.
The use of orthotics in these cases yields very satisfying results. I have seen
great results with athletes of all sizes, shapes and sports.
If time and or money are an issue, posting to the patient’s sock liner
or off-the-shelf insert can be useful. This works great “in a pinch”
such as with a transient patient or an athlete at a competition.
When performing weight-bearing casting, such as Foot Levelers, the doctor is
generally limited to choosing the style of orthotic. The lab customizes the
orthotic to the cast of each patient’s foot.
Without a doubt the most important and often overlooked element the chiropractor
brings to the casting of orthotics is their ability to adjust the foot before
casting. It makes little sense to construct an orthotic to conform to a subluxated
foot. I have seen 4-8° changes in the forefoot varus and elimination of
any rearfoot angle after adjusting. If these athletes’ feet had not been
adjusted the orthotic would have been wholly inappropriate. My personal preference
is to adjust the foot for a few visits before casting if possible.
Hard/Rigid vs. Flexible
Early orthotics were completely rigid. While there is the need in certain populations
for this type of orthotic, most chiropractors use a semi-rigid or flexible orthotic
for their athletic populations. My personal favorite for athletes is graphite.
It is absorbs shock well, is very durable and light weight. Placing a heavy
orthotic in an athlete’s shoes is a guarantee for dissatisfaction.
The ability to fit orthotics in a variety of competition shoes is another key
decision maker when choosing a company. I have made orthotics for hockey skates,
cycling shoes, soccer cleats, track spikes, etc. To insure proper fit you can
send the shoes in question to the orthotic manufacturer. This should yield great
results in terms of fit and performance.
Break-In Period
Most manufacturers recommend wearing the new orthotics for one hour the first
day and adding an hour each day until wearing them full-time. For the athlete
this becomes challenging. Some doctors will initially have the athlete wear
the orthotics when not training or competing, then add training, then add competition.
Other doctors, depending on the nature of the athlete’s condition, will
immediately have the athlete wear them full time. Placing an athlete that does
an explosive event or highly skilled event immediately into the orthotics does
present a certain risk. I have done both, and variations in between, with good
result. Experience and common sense should guide your decision.
Don’t Forget Rehab
Standard rehab activities for the feet are also useful as is training the patient
to do the short foot exercises developed by Freeman and Janda4.
This form of active care, when done properly, can retrain the muscles and proprioception
of the lower extremity. By doing so you should be able to lessen the athlete’s
dependence on the orthotics.
Another Tool in the Toolbox
If you care for athletes you will find the addition of orthotics to your toolbox
will be of benefit to your patients and your bottom-line. It has often said
that every patient would benefit from orthotics but not every patient needs
them. Many athletes will benefit from the purchase shoes with better support
and or replacing old worn out shoes. The good news with orthotics is a positive
change, even less than optimal, will yield good results. Another option is to
work with a podiatrist. You adjust the athlete’s feet and the podiatrist
crafts the orthotics. When in doubt it is good to confer with a fellow professional.
As with any task in clinical practice there is the skill itself and the art
that accompanies it. One can typically learn the skill quickly but the art takes
time and experience. If you are interested in learning more about prescribing
orthotics to your patients I highly recommend the CCEP modules on the lower
extremity5. Many of the companies that sell orthotics and
or the computerized scanning devices offer seminars as well. For a fine list
of reference articles and books on orthotics visit the website of ProLab Orthotics
Inc.6
References
Provide your feedback on this
article.
© Copyright Today's Chiropractic 2005 Today's Chiropractic