Flatfeet

The term flatfoot is a subjective term that is used to describe a foot with a decreased or absent arch. Flatfeet can be acquired or hereditary. The vast majority of flatfeet are hereditary. Just as we inherit facial features, eye color and hair color of our parents, we also inherit a set of bones and joints that function much like those of our parents and grandparents. The vast majority of flatfeet are benign and will never have a significant impact on the person, their lives or their occupation. Occasionally though we see specific types of flatfeet that are real trouble makers. Let's talk about those in a little more detail.

Pediatric Flatfeet

Pediatric flatfoot is a problem seen often in a podiatrists office. Children usually don't have the verbal skills to express themselves with any degree of accuracy regarding medical problems. But children will give us indirect clues or indications of a problem. They'll ask to be carried or they'll want their legs and feet to be rubbed. And in the case of a symptomatic flatfoot, children will tend to express these complaints more so after they've been active. Pediatric flatfoot symptoms are due to the mechanical inefficiency of the flatfoot. Simply put, 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 cause pain and can be of significant concern. There are several congenital (from birth) deformities that we see that result in flatfeet. One of the more common congenital deformities 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. MRI can be very helpful in the diagnosis of a tarsal coalition.

Adult Flatfeet

The inherited 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 just talked about, only they've grown up to become adults.

A second type of adult flat foot is an acquired flatfoot. An acquired flatfoot can be due to many different reason including trauma, arthritis and tendon rupture. Acquired flatfeet can be unilateral or bilateral and can be some of the more challenging flatfoot cases to manage. The most common symptomatic acquired flatfoot that I see is due to posterior tibial tendon dysfunction (PTTD). The posterior tibial tendon originates beneath the calf, descends 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. PTTD is more common in women and is seen with increasing frequency with increased age.

Treatment of Flatfeet

Treatment of pediatric and adult flatfeet depends upon each individual patient's symptoms. Pain should be the primary motivation for treatment. Treatment starts with a simple conservative approach in most cases.

Initial treatment of pediatric flatfeet starts with pediatric arch supports and shoe modifications. Arch supports can be OTC or prescription. Shoe modification can be performed by your pedorthist or shoe repair shop and include an arch cookie (glue in support) and reverse Thomas heel. A traditional Oxford shoe is the most common style of shoe that can accommodate these modifications. The key to initial treatment is to try the simple tricks and see how well 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.

Initial treatment of the adult flatfoot is much the same as we've discussed with children. Try the easy things first such as an OTC rigid carbon graphite orthotic 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 with the primary surgical objective being to 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. 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.

Flexible vs Rigid Flatfeet

When a patient is evaluated for flatfoot surgery, one of the first consideration made in surgical planning is whether the foot is flexible or rigid. Determining flexibility vs rigidity is a bit subjective. Your doctor will manipulate the foot to determine the degree of flexibility. This determination is important in defining the surgical treatment plan. Flexibility is assessed in all three cardinal planes; frontal, transverse and sagital. Flexible flatfeet can be treated with a number of procedures that are ambulatory with little post-operative disability. Rigid flatfeet, on the other hand, require a higher intensity of care with subsequently longer period of post-op care.

Surgical Treatment of Flexible Flatfeet

One common procedure used to treat flexible flatfeet involves placing a small metal 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. Sub talar arthroeresis is often performed with a procedure to lengthen the calf muscle and/or Achilles tendon. These procedures include an endoscopic gastrocnemius recession and/or Achilles tendon lengthening.

The following images show the steps used to perform a STA-Peg procedure. A STA-Peg procedure was one of the earliest methods of subtalar arthroeresis. 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.

The following video shows subtalar arthroeresis being performed using a conical implant.  There are a number of companies who manufacture conical subtalar implants.  This procedure is performed on an ambulatory basis, using either sedation and a local anesthetic, or general anesthesia.  This method of subtalar arthroeresis take about 20 minutes to complete.  Most patients are able to bear weight on the foot the same day.



The next procedure that we'll describe to treat a flexible flatfoot is a modified Kidner procedure. The pictures below show the steps used to perform 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.

Surgical Treatment of Rigid Flatfeet

Surgical treatment of the rigid flatfoot requires making structural changes to the bones and joints of the foot. The primary focus of these procedures is to realign the center of gravity of the body over the foot. These structural changes can be made in one or all three of the cardinal body planes as described above.

The majority of rigid flatfoot cases require an osteotomy of the heel to realign load bearing on the heel. Calcaneal osteotomies are used to correct frontal plane flatfoot deformities. An osteotomy of the heel is a surgical break through the body of the heel. This procedure is normally completed through a 3-4 cm incision on the lateral aspect of the heel. The heel bone is then shifted medially (towards the arch of the foot) and fixated with a screw or pin. This procedure carries many names including a calcaneal slide procedure or calcaneal off-set osteotomy. A calcaneal slide procedure needs to be performed in a hospital setting under general anesthesia. 6-8 weeks of non-weight bearing casting is required following this procedure.

Sagital plane flatfoot deformities are address with either an Achilles tendon lengthening or endoscopic gastrocnemius procedure. Clinical assessment of most adult flatfeet will show that equinus is present and needs to be addressed by either of these two procedures.

Medial column fusions are common in the treatment of a rigid flatfoot. Medial column fusions address frontal and sagital plane deformities. The location for the medial column fusion is determined on x-ray. In a lateral x-ray of the foot, the lowest portion of the arch is identified. The low section of the arch will typically be the talo-navicular joint or the navicular cuneiform joint. One or more of these joints is fused in a medial column fusion. These procedures need to be completed in a hospital stetting under general anesthesia. A 6-8 week period of non-weight bearing casting is common.

Another method employed in treating flatfeet include a procedure called an Evans Procedure. An Evans Procedure is used to correct abduction of the forefoot. Abduction is a transverse plane deformity. 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.

Rigid flatfeet are also treated with a number of different tendon transfers. The most common tendon transfer used in flatfoot surgery is the transfer of the flexor hallucis longus tendon to the posterior tibial tendon. The posterior tibial tendon is the primary tendinous support of the medial arch. The posterior tibial tendon often fails in cases of flatfoot. Tendon transfers such as this serve to reinforce the PT tendon.

The treatment of a rigid flatfoot deformity can be challenging for both surgeon and patient. When planning rigid flatfoot correction, it's important that patients understand the degree of disability associated with the procedure. It is not unusual for many patients to bee off work for a period of 6 months or more when undergoing a rigid flatfoot repair.

Abduction (abducto) - a motion of the forefoot out and away from the mid-line of the body

Pes - Latin, referring to foot

Planus - Latin, referring to flat

PTTD - posterior tibial tendon dysfunction

Tarsal coalition - a bridge of bone that inhibits normal bone growth in the foot and contributes to a flatfoot

Valgus - a motion of the foot out and away from the mid line of the body

The anatomy of a flatfoot is much the same as a 'normal' foot. The difference between flat and normal arches is simply the alignment of the structure within the foot. Differences in the structure of the foot can been seen on a lateral x-ray where a drop or fault is found in the arch of the foot. The fault can be a vary in location and severity.

One anatomical issue common to most flat feet is equinus.  Equinus limits the range of motion at the ankle and is a primary contributing cause to most pediatric and adult flatfeet.

The single most common contributing factor to flatfeet is equinus. Equinus refers to a tight calf and Achilles tendon. The term equine is Latin for horse. This term is used because horses walk on their toes and don't allow their heels to touch the ground. When the term equinus is applied to lower extremity biomechanics, it means that the calf and Achilles tendon limit the normal range of motion of the ankle.

Equinus can be a deforming force that is applied to the foot from the time a child begins to walk. If the tightness of the calf and Achilles tendon are significant, and the arch is resilient and strong enough to withstand the force of the calf, the child will be a toe walker. But in the majority of cases, the arch is weak and will collapse or deform under the biomechanical load generated by the calf. The collapse of the arch due to equinus provides a small amount of dorsiflexion of the foot (toes towards the shin) to enable normal walking.

Symptoms of a flatfoot may include fatigue, pain and an inability to keep up with others for any distance or time on your feet. The symptoms of flatfeet depend upon many variables. These include;

The severity of the flatfoot.
The rigidity vs flexibility of the foot.
The time spent on the feet in recreation and work.
The type of shoes and inserts used to help support the foot.
General physical condition and body weight/body mass index.

Fracture of joint subluxation.

PTTD (posterior tibial tendon dysfunction).

Tarsal coalition.

• Posterior Tibial Tendon Dysfunction

• Cramping Of The Foot

• Pronation

• Arch Pain

• Ankle Pain

This article was written by Jeffrey A. Oster, DPM and last updated 2/5/13.

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