A
flatfoot is a subjective term that describes a foot with a decreased or absent
arch. The loss of arch is usually an inherited trait that is passed from
parents to children. There's a number of
biomechanical and developmental reasons why this occurs, but in most
cases, the condition is benign and will never have a significant
impact on that patient over the course of their lives. Occasionally
though we see specific types of flatfeet that are real trouble makers.
We can talk about those in a little more detail.
How
and why does a person get flatfeet? Those are the two important questions to ask when differentiating between
the simple (non-pathological) and the not so simple (pathological) types of flatfeet.
The most common flatfoot is a simple asymptomatic
flatfoot. This type of flatfoot is present when a child first
begins to walk. Many of the moms that come in the office joke that
their child has their dad's feet indicating that he also has no
arch. We don't actually inherit this type of flatfoot per say, but
we inherit bone structure and biomechanical traits that are very similar
to those of our parents. It's really no different than the way we
inherit the color of our eyes or the color of our hair. We'll walk
and move much like our parents do and if they have flatfeet we
probably will too.
Children are challenging patients to treat because they don't have the ability to express themselves and
tell you where or how they hurt. Children will give us indications of a problem. They'll ask to be
carried or want their legs and feet to be rubbed. A child with the
common type of flatfeet that we've already mentioned will express these complaints, particularly when they've been very active.
These symptoms are due to the mechanical inefficiency of the
flatfoot. It just takes more work to walk with a flatfoot.
Therefore, kids with flatfeet have to exert more effort during a day to
keep up with the other kids.
Although most pediatric flatfeet are
asymptomatic, there are several different types of pediatric flatfeet that can
be of significant concern. There are a number of specific congenital (from birth)
deformities that we see that result in flatfeet. One of the more
common is called a
tarsal coalition. Tarsal refers to the bones of
the rear portion of the foot and coalition refers to a bridge. What
happens in cases of tarsal coalition is that a coalition or bridge of
bone forms between two bones, limiting the range of motion of the joints
of the foot. The end result is a rigid, painful flatfoot. This is
a challenging condition to diagnosis in young children. The challenge lies in the fact
that the radiographic findings of tarsal coalition don't become evident until the late teens. Part
of the diagnostic challenge lies in the fact that the bridge of bone in
young children is made of fibrous material and cannot be seen on
x-ray. As the patient matures, the fibrous bridge begins to ossify
(turn to bone). As this ossification progresses, the foot becomes
markedly rigid and painful.
The adult flatfoot can have
many of the same problems that we've already discussed in
children. The majority of adults with flatfeet simply complain of fatigue and an
inability to get through the day comfortably. These are the same
kids that we've talked about, only they've grown up.
Occasionally adult patients
will develop another type of flatfoot referred to as an acquired
flatfoot. An acquired flatfoot can be due to many different reason
such as trauma, arthritis etc. Acquired flatfeet can be some of the more
difficult flatfoot cases to manage. The most
common symptomatic acquired flatfoot that I see is due to a condition
called
posterior tibial tendon dysfunction (PTTD). The posterior
tibial tendon originates beneath the calf, comes down along the inside
of the ankle and inserts into the arch. Its' primary function is to support the
height of the arch. When this tendon is damaged and becomes 'dysfunctional' the
bones and joints of the arch begin to collapse. We'll see PTTD in many elderly
women. One day they have an arch, the next day they don't.
Treatment of Flatfeet
Treatment
of flatfeet really depends upon the symptoms that they may cause. Pain should be the
primary motivation for treatment. Obviously we start out with a
simple conservative approach in most cases.
The vast majority of
children can be treated with
arch supports and shoes. This could be
an arch support that the shoe repair shop glues into the shoe, it could
be a store bought arch support or even a custom made arch support called
an orthotic. The key is to try the simple tricks and see if they
work. How do you know that they're working? You'll simply
see a decrease in symptoms. The other consideration with kids is
that they're going to grow out of things so quickly. I think it's
money well spent to discuss your concerns with your podiatrist or
pedorthist.
They'll be able to recommend a treatment plan that may be significantly
more cost effective for your child in the long run.
Treatment of the adult
flatfoot is much the same as we've discussed with children. Try
the easy things first such as
arch supports and eurocomfort shoes.
You'd be amazed at what a decent pair of comfortable shoes can do to
change a persons life. If the symptoms of a
flatfoot don't
respond to conservative care, consult your podiatrist. I would
also like to stress that early treatment of some of the conditions that
we've discussed, like PTTD, is very important. We've
discussed the fact that PTTD is due to failure of the posterior tibial
tendon. In the early stages of this condition, the tendon is inflamed
and can be corrected. If the condition is allowed to progress, the
tendon will eventually rupture leading to a surgical correction that can
be quite extensive. Conservative care of adult flatfeet includes
traditional Oxford shoes,
arch
supports, orthotics,
OTC braces
and Rx braces.
At first
glance, flatfoot surgery would seem fairly simple; raise the arch. But in actuality
it's much more complex than that. Much of the stability of the
foot comes from the bones of the rearfoot. If a house has a bad
basement, the rest of the house is in jeopardy. The same holds
true for the foot. A faulty rearfoot jeopardizes the stability of
the rest of the foot.
In addition to correcting
the arch, we also need to consider how to restore the center of gravity
over the foot. How do we center the weight of the body over the
foot? Quite often in flatfoot cases we see the arch collapse and
the foot rolls in forcing the center of gravity to be carried somewhere
out over the inside of the foot. That's a very important
consideration when repairing flatfeet. We also discussed the
impact of a tight Achilles tendon in children and its affect on the
development of the foot. Quite often I'll lengthen the Achilles
tendon in flatfoot repair cases.
Many flatfoot correction procedures involve a
wedge resection of the arch or heel. As the wedge is closed, a new arch is
formed. Other procedures require fusion of the joint to created
needed stability. Many of these cases require prolonged casting to
allow for proper healing.
Another
type of procedure involves placing a small implant in the subtalar joint
to 'wedge' the foot and ankle into a more stable position. This procedure is referred
to as a subtalar arthroeresis (STA-Peg procedure). Arthroeresis is not as invasive as other forms
of surgical arch reconstruction, but may only be used in select cases of
flexible flatfeet. Subtalar arthroeresis is often referred to as
an internal cast, supplying support from within the subtalar joint.
The following images show the steps used to perform a STA-Peg
procedure. Image 1 shows pre-operative planning marking the boundaries of
the peroneal tendons and intermediate dorsal cutaneous nerve. In image 2
wee see the peroneal tendons retracted down and the intermediate dorsal
cutaneous nerve retracted up. Image 3 show entry into the subtalar joint.
Image 4 and 5 show preparation of the of the subtalar joint for the implant.
And image 6 shows the implant in place. The capsule of the subtalar joint
would be closed and skin reapposed with several non-absorbable sutures.
patients can bear weight on the foot the same day. STA-Peg implants come
in three sizes. Image 7 shows the implants and their corresponding
insertion/sizing tools.
Other methods employed in treating flatfeet include a procedure
called an Evans Procedure. An Evans
Procedure
is used to correct abduction of the forefoot. The test used to determine
the amount of abduction of the forefoot is called a 'too many toes sign'.
In cases of extreme forefoot abduction, when the foot is viewed from the back,
the 4th and 5th toes will be seen peeking out along the lateral aspect of the
foot. The Evans procedure is used to wedge the foot back to a straight, or
non-abducted position. An Evans procedure uses a bone graft to wedge the
distal calcaneus, in effect lengthening the lateral column of the foot. An
Evans procedure may be used in conjunction with any number of other flatfoot
procedures.
The pictures below show the steps used to perform another common
flatfoot procedure called a modified Kidner procedure. A modified Kidner
is often used in conjunction with other procedures to correct a flatfoot
deformity. A modified Kidner procedure is also used in cases of a
symptomatic os tibial externum (accessory bone of the medial arch as seen in the
image to the left).
Image 1 shows the planned approach with the leg to the left and
toes to the upper right. Image 2 shows deep tissue dissection and
identification of the posterior tibial tendon sheath. Images 3-5 show
dissection of the os tibiale externum from its' investment from within the
posterior tibial tendon. Image 6 shows repair of the posterior tibial
tendon with non-absorbable suture. Image 7 is final skin closure.
Image 8 shows the articular surface of a large os tibial externum.
Os tibiale externum is found in 15% of the general population and functions in a
way similar to your knee cap (patella), enabling its' associated muscle and
tendon to function more effectively. The os tibiale externum articulates
(forms a joint) with the navicular bone. Pain due to a symptomatic os
tibial externum is often due to arthritis at this articulation. The forceps
point to a focal area of degenerative change consistent with may be called
osteochondritis dessicans. Osteochondritis dessicans describes erosion of
cartilage that results in arthritic changes.
A modified Kidner procedure is performed on an out-patient
basis using general anesthesia and a thigh tourniquet. The
procedure takes approximately an hour to perform. Inherent in the
term modified, a modified Kidner may include several additional steps
not described in these pictures. Additional steps may include
tendon transfer or tenodesis (anchoring the tendon to the bone).
Post-op care may include a bandage, splint or cast. Some patients
may ambulate following this surgery, others may not. The size of
the os tibiale externum dictates whether a patient may walk post-op or
not. The percentage of space taken up by the os tibiale externum
within the tendon may be significant enough that immediate weight
bearing would result in failure of the posterior tibial tendon.
Your surgeon will be able to determine when you can return to ambulation
during the procedure.
The long-term success or failure of a modified Kidner procedure
can depend upon the treatment of the associated flatfoot. If the
flattening of the foot is allowed to continue following a modified Kidner,
continued stress will be placed upon the posterior tibial tendon. In some
case, this will lead to failure of the PT tendon. Therefore, it is
imperative to address the flatfoot at the time a modified Kidner is performed.
A common procedure that would accompany a modified Kidner would be subtalar
arthroeresis, medial column arthrodesis or lateral column lengthening.
