Bone is a phenomenal tissue that has the ability to change, grow
and restructure itself based upon the loads we apply to it. Bone
gives our bodies support and structure, it protects our many
vital organs and it acts as a reservoir for the important
minerals we need every day.
Think of the bone structure of your feet as shock absorbers, in
fact they act much as do the shock absorbers on your car. We
expect our cars to have a smooth consistent ride regardless of
loads that we put in the car like groceries or people. Those
loads are constantly being added or removed from our cars, yet
the shock absorbers provide a smooth consistency over their
functional lifespan. Our bones work in much the same fashion and
yet are a much more dynamic structure, able to change when we
change.
Let's say we start to work out at the gym. We plan to get big
muscles to impress our significant other. What supports those
muscles? That's right, bone. Our new fitness plan increases
loads applied to bone causing it to grow to be able to accept
those new loads. The opposite holds true also, decrease your
activity and your bone mass will decrease. That's why it's so
important for seniors to maintain regular physical activity.
The bones of the foot are a very complex set of structures
designed to carry load. Each foot consists of 26 different bones
and 114 ligaments. That number is complex enough but when we
bear weight and begin to walk, all of these bones move and
change. The interesting part of my job is that the bones of the
foot are constantly changing. For instance, when I exam a
patient in my office, even though they are sitting in a
treatment chair, I am visualizing what the foot and all the
bones are doing while that patient is walking
A fractured bone simply is a broken bone. There are many
sub-definitions of the term fracture. For instance, a compound
fracture is an irregular fracture that has broken through the
skin. A comminuted fracture is one that is in many pieces. There
are any number of different varieties of fractures that we see
in the foot.
Fractures can occur for many different reason. We tend to think
mostly of trauma causing fractures but there may be other
contributing factors. Most of us are familiar with the term
osteoporosis. Osteoporosis means that the density of the bone,
the mineral content so to speak, has been reduced. Patients with
advanced osteoporosis are subsequently more susceptible to
fracture. Bone tumors may also contribute to fractures by
weakening the bone. And lastly, many other systemic or metabolic
diseases may contribute to change in bone that may result in a
fracture.
Stress fractures are quite common to the foot. We mentioned
before that bone carries load. A stress fracture simply implies
that the load applied to the foot was greater than what the bone
could tolerate, so it breaks. The most common stress fracture
that occurs in the foot is in the metatarsal bones. These
fractures are also referred to as march fractures. The name came
about as the result of forcing young, sedentary army recruits to
march 20 miles with a full backpack. Their transition from
civilian to soldier was too abrupt resulting in a load that was
greater than what the metatarsal bone could tolerate.
The onset of a metatarsal stress fracture is somewhat subtle.
Let's look at a few case examples.
Case 1. Bob, 32 years old, was on a business trip in the Atlanta
Airport and was late for his plane. He had to go from concourse
A to concourse Z carrying his luggage. When he finally got on
the plane and sat down, he felt a dull ache in the forefoot that
just wouldn't go away. After a week of limping around he
contacted us.
Case 2. Ethel was a retired housewife who lived on a rural
farm. Her husband had sustained a severe heart attack and was at
home but was required to stay in bed. Therefore, Ethel was
obligated to do a lot of the chores that here husband had done
in the past. Ethel mowed her large yard with a push mower, and
while mowing she noticed a dull ache of the left forefoot. The
pain did not resolve over the next few days and she made a call
to come see us.
You can see Bob and Ethel represent two very different people
but the onset of the stress fracture is very similar. Each
presented dull achy pain just behind the toes. It hurt to bear
weight on the foot. The more they were on their feet, the more
swelling they would see on the top of the foot. Getting a shoe
on, and keeping it on was tough.
X-rays are necessary but aren't always so helpful with
metatarsal stress fractures. In most cases, metatarsal stress
fractures can only be seen on x-ray three to four weeks after
they occur. X-ray findings of metatarsal stress fractures are
very subtle in nature. We don't actually see the fracture, but
we see the deposition of calcium surrounding the fracture as the
bone heals. This finding is referred to as bone callus and is
the body's own internal cast, so to speak.
Other stress fractures of the foot include the calcaneus and
navicular bones. These are bones of the rearfoot that support
the loads applied to the foot during standing or jumping. These
fractures are difficult to diagnose and are often treated as
arthritis or other inflammatory condition. An MRI will aid in
the diagnosis of calcaneal and navicular stress fractures.
Treatment for calcaneal or navicular stress fractures depends
upon the location and severity of the fracture.
The technique of treating fractures varies on a fracture by
fracture basis but the fundamental principles are the same. The
first thing we have to do is to confirmed on X-ray that the
fracture is stable, it's well aligned and that the ends of the
fracture appose each other. Once we've done that, we find ways
to help the bone heal. In most cases this is a variation of
rest. It could be bed rest, a cast, a fracture shoe or just
decreasing activity. As you can see, each of these methods of
treatment is a variation of rest. Most stress fractures of the
foot will heal over time with just a little help. Patients are
usually surprised to find out that a stress fracture takes 8-12
weeks to heal.
Nomenclature:
Bone callus - describes the increased area of initial fibrous
tissue, and finally calcified tissue surrounding a fracture.
Bone callus helps to stabilize the fracture acting as an
internal cast.
March fracture - a term used to describe a stress fracture that
results from marching in the armed services.
Symptoms:
Symptoms of stress fractures may vary. Symptoms may include
localized swelling (edema) and pain that increases with the
duration of time spent on the feet. Differential Diagnosis: The
differential diagnosis for this condition should include;
Morton's neuroma
soft tissue tumor
About Author :
Jeffrey A. Oster, DPM, C.Ped is a board certified foot and ankle
surgeon. Dr. Oster is also board certified in pedorthics. Dr.
Oster is medical director of