Orthotics
Our professional partners prescribe orthotics to their patients for various symptoms. Many medical conditions often stem from a biomechanical gait abnormality that can be treated with custom orthotics. Here are some common ailments related to poor foot biomechanics.
Achilles Tendonitis
Achilles Tendonitis is an inflammation of the
common tendon of the gastrocnemius and soleus muscles of the posterior
compartment of the leg. Patients that have equinis deformity and/or run
up-hill are candidates for this disorder. As the tibia moves over the
foot, the ankle joint needs to be able to dorsiflex at least 10 degrees.
If this is not possible, due to tightness of the aforementioned
musculature,the tissues of the tendon can be damaged. In addition it is
thought that over-pronation may reduce the blood supply to the area by
"wringing out" the arterial blood supply to the tendon. This is due to the
twisting movement of the tendon associated with over pronation of the
foot.
Iliotibial Band Syndrome
The iliotibial band which is a thick extension
of the tensor fascia lataemuscle slides over the lateral epicondyle.
Iliotibial Band Syndrome is an inflammatory reaction at the side where
this sliding occurs. If the foot over-pronates, this is accompanied by
internal rotation of the entire lower limb, producing a constant friction
between the band and the bony prominence of the femur. It is therefore
very common among runners especially if they run on a banked track or
downhill.
Metatarsalgia
Metatarsalgia is not an injury; it's actually a
symptom or a group of symptoms. These may include pain in the ball of the
foot, with or without bruising, and inflammation. It is often localized in
the metatarsal heads or it may be more isolated, in the area near the big
toe. One of the hallmarks of this disorder is pain in the ball of the foot
during weight-bearing activities. Sharp or shooting pains in the toes also
may be present, and pain in the toes and/or ball of the foot may increase
when the toes are flexed. Accompanying symptoms may include tingling or
numbness in the toes. It is common to experience acute, recurrent or
chronic pain as a result of this problem. Metatarsalgia develops when
something changes or threatens the normal mechanics of the foot.
Ultimately, this creates excessive pressure in the ball of the foot, and
that leads to metatarsalgia. Some of the causes of metatarsalgia include:
Being overweight: the more weight is brought to
bear on the foot, the greater the pressure is on the forefoot when taking
a step.
As men and women age, the fat pad in the foot
tends to thin out, creating less cushioning and making them more
susceptible to pain in the ball of the foot.
Wearing shoes that do not fit properly: Shoes
with a narrow, tight toe box, or shoes that cause a great deal of pressure
to be put on the ball of the foot (high heels, for example) are often the
cause of metatarsalgia. Because such footwear inhibits the walking process
and forces the wearer to alter his
or her step to adjust to the shoe, the mechanics
of the foot are
compromised.
Certain foot shapes contribute to metatarsalgia.
A high-arched foot, or a foot with an extra-long metatarsal bone can cause
pressure on the forefoot region and contribute to pain and inflammation
there.
Claw toes or hammertoes can press the
metatarsals toward the ground and cause stress on the ball of the foot.
Arthritis, gout or other inflammatory joint
disorders can produce pain in the ball of the foot.
Morton's Neuroma
Morton's Neuroma is a thickening of the tissue
that surrounds the intermetatarsal nerve leading to the toes. When the
nerve becomes squeezed and irritated, it causes painful symptoms. Neuroma
patients occasionally complain of a "pins and needles" sensation that
spreads through their fourth and fifth toes, or of a feeling akin to
hitting their "funny
bone." A neuroma can occur in response to the
irritation of a nerve by one or more
factors:
Abnormal foot function or foot mechanics:
primarily excessive pronation that causes strain on the nerve.
Improper footwear: constricting, narrow,
poor-fitting shoes with a tight or pointed toe box tend to compress the
end of the foot, leading to excessive
pressure in the area of the nerve. High-heeled
shoes are a particular culprit here.
Previous trauma to the foot: Those who engage in
high-impact activities that bring repetitive trauma to the foot (running,
aerobics, etc.) have a greater chance of developing a neuroma.
Plantar Fasciitis
Plantar fasciitis is an inflammatory condition
that occurs where the plantar fascia attaches to the medial tuberosity of
the calcaneus. Over-pronation results in a const ant tugging of the
aforementioned attachment site. Inflammation then results from this
constant insult to the local tissues. When the patient is off- weight
bearing, scar tissue begins to repair the site of injury. When the patient
resumes weight-bearing, the scar tissue is torn resulting in acute pain.
This explains why patients with this disorder typically experience the
most pain when they get out of bed, or stand after a period of sitting
Runner's Knee
Runner's Knee is a general term referring to
pain around the front of a runner's knee. If the pain is anteromedial in
location, the source of the problem may be over-pronation. The internal
rotation of the tibia associated with overpronation, may cause the knee to
fall into a functional valgus orientation during the stance phase of gait.
This in turn will compromise the ligaments on the medial aspect of the
knee. Furthermore, the abnormal motion will result in abnormal pressures
behind the patella, leading to a more specific knee malady referred to as
chondromalacia patella.
Sacroiliac Syndrome
Sacroiliac syndrome is a painful inflammatory
condition of the sacroiliac joints. The patient generally experiences pain
in the buttock and thigh regions. It is typically aggravated by sitting
for long periods. Quite frequently it is caused by an injury such as would
be sustained by a fall on the buttocks or during a lifting activity.
However, there is some evidence to suggest that a chronic irritation from
abnormal foot mechanics is also a possible cause. When a foot
over-pronates, it creates a tendency towards internal rotation of the
lower limb. Due to the anatomy of the hip joint, this internal rotation
translates into an extension of the pelvis (PSIS's rotate upward while
ASIS's rotate downward). If the mechanics of the feet are not symmetrical,
then conflicting rotations may occur at the two sacroiliac joints. This
appears to set up a chronic irritation of these joints leading to the
inflammation.
Shin Splints
The condition known as Shin Splints involves a
muscular over-use scenario. There are Anterior Shin Splints and Posterior
Shin Splints. Anterior Shin Splints involve the Tibialis anterior muscle
of the anterior compartment of the leg, and Posterior Shin Splints involve
the Tibialis posterior muscle of the posterior compartment of the leg.
Both of these muscles are involved in slowing down pronation during the
stance phase of gait. Tibialis anterior functions early in the stance
while Tibialis posterior functions a little later. If the patient
over-pronates or pronates too rapidly, either or both of these muscles may
be called upon to work harder than normal. As a result, fatigue sets in,
leading to inefficient force production which leads to micro-tearing of
the soft tissue and therefore and inflammatory reaction. Since the muscle
is wrapped in a fascial covering, the swelling that occurs from the
aforementioned problem is restricted by this covering. Beyond the fact
that much pain results from the entire process, the pressure within the
fascial covering can be sufficient to "choke-off" the blood supply to the
involved musculature, further added to the insult on the tissue. In severe
circumstances the swelling can be severe enough to damage the deep
peroneal nerve resulting in a permanent "foot drop," as this nerve
supplies the dorsiflexors of the foot. The scenario that typically brings
on "shin splints" is a sedentary individual that suddenly starts running
or walking long distances. When that individual is also an over-pronator,
the combination of having weak muscles from lack of activity and having
this biomechanical fault increase the likelihood of injury. Even changing
the type of shoe worn during walking or running can be sufficient to
increase the pronation of the subtalar and transverse tarsal joints and
lead to tissue injury.

