The human foot is one of the most amazing
and complex pieces of machinery in the human
body. It is composed of twenty-six
bones, each with a particular shape and position,
specific to its function. The plantar,
or bottom, surface of the foot is composed
of a series of arches that are designed to
conform to various surfaces and absorb impact. The
largest and most obvious of these arches
is the medial longitudinal arch. It
spans from the medial ball of the foot to
the inside of the heel. As you will
see in the following paragraphs, the medial
longitudinal arch is the most important determining
factor in both foot and knee positioning
during the gait cycle.
When we look at the design of the foot from
an evolutionary perspective, it is apparent
that the uneven surface of the foot was not
designed for a hard flat surface. Ligaments
hold the numerous joints of the foot together
to prevent collapse and insure that joints
are articulating properly. Four layers
of muscles contract during movement to create
proper balance and positioning. Together,
the combination of these structures give the
sole of the foot the ability to conform and
adapt to whatever it comes in contact with.
The knee, by contrast, is a far less complex
structure. The knee joint is composed
of three bones, six primary ligaments, and
five primary muscles. These structures
function as a one-way hinge separating the
upper and lower leg. Unlike the foot,
the knee has limited ability to adapt to uneven
forces.
Unequal distribution of force in the foot
is dispersed throughout the entire joint system. During
impact with the ground, the medial longitudinal
arch compresses and absorbs force much like
the shock in an automobile. If the primary
arch of the foot bottoms out, then the remaining
force is transferred to the ankle and knee. The
ankles are an extension of two long bones in
the lower leg; the tibia and fibula. These
two long bones rest atop a base bone called
the talus. This articulation offers more
movement than the knee joint, but has far less
ability to absorb shock than either the knee
or foot. The knee joint is composed of
two primary articulating bones, the femur (upper
leg) and the tibia (lower leg). The femur
and tibia are separated by two disc-like structures,
the menisci, which are designed to absorb excess
force that passes beyond the foot and ankle. With
all of this machinery working together to control
motion and absorb shock, why is the incidence
of pain in the these areas so common?
The knee was the second most common location
for pain in Americans in 2004, per the American
Medical Association. Recent studies indicate
that the frequency of knee pain has increased
steadily (per capita) since the 1950’s. Anatomically,
our bodies have not changed in millions of
years. What has changed however, is our
environment. Our country has steadily
been covered by concrete and asphalt over the
last one hundred years. Today, we are
lucky if we walk on grass ten or fifteen minutes
a month. Despite tremendous advancements in
shoe technology, the average foot has not been
able to counteract modern ground forces. The
proof is in the medical files; the incidence
of foot pain, ankle pain, knee pain, hip pain,
and lower back pain continues to increase.
When our feet make contact with hard, unforgiving
ground surfaces, the arches of the foot reach
maximal compression and often cause the foot
to collapse inward. This collapse, or
excessive pronation, creates two major mechanical
problems. The first result is ineffective
shock absorption. The second problem
is uneven tracking of the knee. Prolonged
exposure to excessive force and aberrant tracking
cause chronic inflammation and joint degeneration. Traditional
medical treatment of knee pain has been chemical
intervention to regulate inflammation and/or
surgical intervention to remove the by-products
of degeneration. Unfortunately,
each of these therapies has a poor long-term
success rate. The most likely reason
for the ineffectiveness of knee surgery and
medications is because both of these approaches
address the result (inflammation and degeneration)
rather than the cause of the problem (poor
biomechanics).
The previous paragraphs have summarized the
anatomy and biomechanical relationships of
the foot, ankle, and knee. Although there are
instances when medications and surgery may
be necessary in the treatment of knee pain
(trauma, disease, etc.), a majority of knee
pain can be eliminated by restoring proper
foot mechanics. Custom functional foot
orthotics, when designed properly by a licensed
professional, can counteract modern
ground forces and restore proper mechanics
to the entire lower extremity. Go to
www.getfootsense.com for more information.
Statistical information was obtained and summarized
from the following websites
