Flatfoot in children

Flat foot in children

Introduction

Flatfoot is a term cosmetically applicable to all the feet which have a decreased or absent arch on weightbearing. Foot arch is present because of normal bony alignment with proper soft tissue tension.  We must remember that dynamic flexibility of foot is more important than static posture of foot. Presence of flatfoot should not be taken as abnormal in most cases. It can be considered a variant of foot just like straight hairs and curly hairs. It does not mean all newborns must have an arch at birth. A normal arch is expected to develop spontaneously by age of 5-7 yrs, hence a flatfoot in toddlers can be normal. It is due to ligamentous laxity and fatpad in sole, as they mature and walk, arch develops slowly in most cases. Many of these children who have flatfoot also have similarly affected parents. In fact most of the parents with flatfoot are leading a comfortable and healthy life without any intervention. It suggests to us the benign nature of Flexible flatfoot.

 How do we then know when its not normal and when to initiate treatment? Lets have a closer look.

Types

A flatfoot can be rigid or a flexible one depending upon mobility or on the presence of fixed deformity. Two simple tests which can be performed are : Jack's test and Heel rise test.

In Flexible flatfoot  arch disappears when foot is on ground but reappears when foot is off the ground. Arch also can be noted on extension of great toe (Jack test). In the rigid types it remains unchanged and symptomatic in most cases. When asked to stand on toes we can notice appearance of arch and heel inversion in flexible flatfoot. Rigid flatfoot which remain unaltered in any position are seen in tarsal coalitions, neglected vertical talus and syndromic cases like arthrogryposis.
Single leg rise test helps identify Tibialis posterior insufficiency. In this we ask the child to stand on affected leg and try to rise the heel.
Heel cord shortening can be assessed by asking the child to squat or heel walk.
Any excessive joint laxity, obesity, pain, swelling, angular or torsional deformities in lower limb is be noted.
Sensory and motor examination helps rule out neurogenic cause.

Pic: 1a, Flexible flatfoot: note the normal arch appears on non-weight bearing

Pic: 1b, Flexible flatfoot: Jack's test- Arch seen better on extension of great toe

Pic: 1c, Flexible flatfoot: Arch depressed on weight bearing

Check for joint laxity by trying to touch thumb to forearm

Xrays shows evidence of Acessory Navicular

Intraoperative pic showing Tip post rendon rupture with mucinous changes along its track

Intraop pic showing torn Tip post with fibrillation changes

Pic: 2a Flexible planovalgus : Symptomatic on Right side

Pic: 2b On standing: More toes seen on the outerside of right leg , note the heel lateral angulation. She had a painful right foot with progression of deformity.

Pic:2c On Heel rise: note the number of toes seen outside are less and heel line deviates medially

Pathology

As the arch decreases the normal tripod gait alters. There is attenuation of medial side structures like Talonavicular joint capsule, spring ligament and tibialis posterior. Posteriorly the Achillis tendon gets shortened, laterally peroneous brevis becomes more spastic and contracted. The heel cord instead of pulling in axis of ankle joint pulls laterally, so ankle dorsiflexion happens at subtalar joint instead of ankle. This leads to stress trasfer at midfoot joints, hence pain. Laterally impingement occurs and talus tilts medially and plantarflexes. As the heel goes in valgus forefoot is supinated, with time they become rigid and progressive. Altered mechanics leads to pain and progression with cyclical loading. In congenital vertical talus the medial border is convex and talus head can be palpated facing directly down. In Tarsal coalitions(Pic:3) these deformity are fixed and rigid, but they become symptomatic around 8-12years as compensatory foot flexibility reduces. The common tarsal coalitions are between talus and calcaneum followed by calcaneonavicular (Pic:3a, 3b) one.

In tibialis posterior insufficiency it starts as a simple tenosynovitis of Tip post tendon followed by tendinosis, tears and progression of deformity.

Xrays of a weight bearing foot are necessary. CT and MRI also help to localize the extent of lesion and aid in preoperative planning.

Xrays foot showing calcaneonavicular coliation

Lateral Xray showing Talocalcaneal colaition with beaking of anterior talus

Pic: 3a MRI:Calcaneonavicular coliation Axial cut

MRI: showing tenosynovistis of Tip post tendon

Pic: 3b MRI: Saggital cut Calcaneonavicular bar

Management

All flatfoot do not necessarily need treatment. These points listed below are RED FLAGS and need further referral to a specialist. Remember flatfoot don't need surgery for cosmetic reasons.

• Pain
• Progressive deformity
• Unilateral
• Frequent abnormal shoe wearoff

These symptoms should prompt for further Investigations and consultation with a specialist. Asymptomatic flexible flatfoot do not need any treatment. Symptomatic Flexible flatfoot can be managed initially by calf stretching, strengthening, arch supports and customized orthoses. Any type of shoes or orthotic devices will not restore the arch, no matter how long we use it. They are only supportive measures to maintain the arch either before or after surgery. Rigid flatfoot most of the times need surgical intervention for correction. Tendoachillis gets shorter with progressive deformity.

Symptomatic flexible flatfoot with heelcord shortening must be treated by stretching and UCBLs.
Those flatfoot who remain symptomatic or worsen even after 6 months period of conservative treatment methods are ideal candidates for corrective surgery.

Goal of surgical correction is to reduce the pain, realign the foot, improve range of motion and function.

Surgical correction is achieved by a combination of one of the following:

• Soft tissue procedures - Heel cord lengthening, Tendon transfer, Medial imbrication
• Arthroreisis - Blocking the ankle eversion by putting implant or bone at Subtalar joint
• Bony reconstrution - Calcaneal tuberosity slide osteotomy, Lateral calcaneal neck lengethening osteotomy, Cuneiform plantarflexion osteotomy, cuboid opening wedge osteotomy.\
• Arthrodesis - Salvage procedures like subtalat or triple fusion

In Tibialis posterior insufficiency stage I casting and debridement can be done. Stage II needs debridement and transfer of one of the foot flexors  with calcaneal osteotomy and heelcord lengethening. Stage III and IV needs fusion as salvage procedure.

Here in Pic: 2a-c an example of Flexible flatfoot is shown, she is symptomatic on right side, hence she was put on medial arch support for 6 months. She complained of worsening of pain hence surgical reconstruction was planned.

She underwent Calcaneal lengethening with , peroneus brevis Z lengthening, gastronemius recession and medial plication. Pic: 4a, 4b shows her foot after 6 weeks post correction. She has a significantly improved arch, the heel line from behind is straight and toes are no more seen from behind.Pic:4c shows her postop xrays.
Postoperatively after 6 weeks it is recommended to use arch support shoes and start gradual weight bearing. The plate needs removal after 6-12 months, if soft tissue irritation causes pain (Pic:4c).

Pic:4a Correction achieved after 6 weeks of surgery, arch improved

Pic:4b Note the heel appears better, plz compare with Pic: 2b 

Pic:4c Post op 6 weeks after calcaneal lengetheing

Pic: 4c

HAPPY FEET!