The examination should begin by observing general limb alignment, foot progression angle, and the degree of bow leg or knock knee exhibited while the child is walking with the parent. On standing, the foot appears flat and the heel may show mild valgus [Fig.1].

Figure 1

Figure 1: Bilateral flatfeet (pes planus) with mild heel valgus.

When the child is asked to stand on tip-toe, the arch usually reconstitutes, and the heel goes into mild varus [Fig. 2].

Figure 2

Figure 2: The arches are reconstructed and the heels go into mild varus when the child is on tip-toes.

The ability to stand on the heel demonstrates that the heel cord is not excessively tight. Heel cord tightness should also be evaluated by first ‘locking' the talonavicular joint in inversion and then passively dorsiflexing the foot. Subtalar and ankle motions are full in flexible flat feet. Evaluation of subtalar motion does not consist of simple medial-to-lateral rocking of the calcaneus; this is a common but misleading method of assessing subtalar motion, and only produces tilting in the lax ankle mortice. Instead, the forefoot should be rotated through a range of pronation and supination. Evaluation of the flexible flat foot should also include assessment for ligamentous laxity around the knees, elbows and wrist joints.

The shoes should also be examined. Ordinarily, there is heel wear on the lateral side. Shoes without heel wear may indicate a tight Achilles tendon. Radiographs are rarely indicated for flexible asymptomatic flat feet.

The flexible painless flat foot requires no treatment. Treatment should not be imposed on a child to satisfy the parents. The parents and grandparents should be reassured that the flexible, painless flat foot is a common, benign condition and a variation of normal. They should be informed that shoe modifications or inserts are expensive and may adversely affect the child's self image. In addition, such measures do not influence the course of flexible flat foot. In cases of severe, but flexible, flat foot the medial sole and counter of the shoe can be worn-away and destroyed within a week or two of purchasing new shoes. In such children, one might consider either corrective shoes or shoes with an orthotic insert. If the family insists that something must be done, encourage the use of flexible shoes, limitation of excess weight and a healthy lifestyle for the child. However, because of a cultural tendency to favour corrective shoe wear, the psychological need for parents to provide ‘the best' for their child, and the placebo effect observed when special shoes are prescribed, this rather expensive but probably harmless practice will continue.

It is a commonly held belief that the prophylactic use of rigid orthotics for young athletes with flat feet decreases the risks of injury in this population. Studies have been performed examining the relationship between flat feet and athletic injuries in the lower extremities and the data revealed that the existence of flat-footedness did not predispose the athlete to lower extremity injuries [₂]. Therefore, there is no scientific evidence to support the prophylactic use of orthotics for flat-footed athletes, to prevent future injury.

Flexible flat foot is considered pathological when pain is present in the arch and persists despite proper conservative method. In addition, callosities and abnormal shoe wear are sometimes indications for surgery. Rarely, should surgery be performed before skeletal maturity. A variety of tendon transfers and reconstructive procedures have been advocated, but none have proven uniformly successful. Operative intervention to create an arch by blocking subtalar movement may establish an arch but may damage the subtalar joint and cause degenerative arthritis in adult life. Fusion of the subtalar joint alone or a more extensive procedure, such as a triple arthrodesis, is indicated for severe persistent pain.

The examination varies according to the age of the child. For the first four to five days after birth, the foot lies in an acutely dorsiflexed position with the top of the foot in contact with the anterolateral surface of the leg. The heel is in dorsiflexion, and the forefoot is markedly abducted. When the foot is plantar-flexed, a concavity appears in the sinus tarsi area with the overlying skin becoming taut with attempted plantar-flexion. In more severe cases, the foot cannot initially be plantar-flexed much beyond neutral. Overall, however, the foot is flexible and both the heel and the forefoot can be passively corrected into varus.

It is imperative to distinguish between a calcaneovalgus deformity and congenital vertical talus, and this should be achieved in the first few months of life. The rigid, fixed congenital vertical talus also presents with the foot folded anterolaterally against the tibia, but the heel cord is extremely tight and the hindfoot is in equinus.

The deformity generally resolves spontaneously. Only very rarely is corrective casting necessary. Surgery in the form of extraarticular arthrodesis may be needed in persistent cases, at three years of age.

The deformity reveals a rigid flat foot. The heel is in equino-valgus with contracture of the triceps surae muscles. The forefoot is dorsiflexed and everted; the arch is convex, because the head of the talus projects into the plantar aspect of the foot [Fig. 3].

Figure 3

Figure 3: Two month old child with congenital vertical talus. The foot is dorsiflexed and the arch is convex.

The foot is stiff and uncorrectable. Some cases are dramatically obvious, but others are easily overlooked. Congenital vertical talus may be confused with flexible oblique talus, a different condition.

Plain radiographs assist in confirmation of the diagnosis. A lateral radiograph in maximum plantar-flexion will, in congenital vertical talus, show the vertical orientation of the talus [Fig. 4].

Figure 4

Figure 4: Lateral radiograph of the foot in maximum plantar-flexion shows the vertical orientation of the talus.

A lateral radiograph in maximum dorsiflexion will show no change in the position of the talus [Fig. 5, Fig. 6].

Figure 5

Figure 5: Lateral radiograph of the foot in maximum dorsiflexion shows no change in the position of the talus.

Figure 6

Figure 6: Lateral radiograph of the normal foot in this two month old child. The talus is normally oriented.

In the innocent, correctable, oblique talus, the bone lines up normally with the metatarsals when the foot is placed in maximum plantar-flexion.

Congenital vertical talus, in contrast to flexible flat foot, requires early surgical correction. A single-stage procedure late in the first year of life is recommended. In patients with motor neuron disorders, treatment involves genetic and multidisciplinary management approaches. Untreated, patients develop an awkward gait due to a painful rigid foot, as well as callosities under the midfoot.

Physical findings include pain on palpation over the subtalar joint, limited subtalar movement and at times pes planus and ankle valgus. The peroneal muscles may be tight and resist inversion (peroneal spastic flat foot). Plain radiographs, especially the 45° oblique view, usually demonstrate the calcaneonavicular coalition and other less common coalitions, such as a calcaneocuboid [Fig. 7].

Figure 7

Figure 7: Calcaneonavicular coalition is demonstrated on the 45? oblique view of the subtalar joint.

The talocalcaneal coalition is difficult to visualize on plain radiography, but secondary changes, which may suggest the need for other studies include talar beaking, broadening or prolongation of the lateral process of the calcaneus [anteater sign] and narrowing of the subtalar joint. Special views [e.g. Harris-Beath], scintigraphy, plain tomography and arthrography have been used to demonstrate these coalitions. Computed tomography, [CT] is the method of choice for the diagnosis of tarsal coalitions. Magnetic resonance imaging [MRI] provides the advantage of demonstrating fibrous coalitions, but it is a more costly technique.

The initial treatment of these conditions should include conservative measures aimed at relieving the pain. These include casting for four weeks and the use of various shoe inserts and orthotics. The main indication for surgical resection is persistent pain. For calcaneonavicular coalition, resection of the bar with interposition of the extensor digitorum brevis is usually associated with good results [₇]. Talocalcaneal coalition is more difficult to recognize and its surgical management is less certain [₈].

The management of these coalitions is still controversial. However, patients with persistent symptoms who do not have degenerative changes have the option of continued conservative care, resection of the coalition or arthrodesis. Resection is likely to fail if coalitions exceed 50% of the middle facet of the subtalar joint.

The predominant radiographic findings are forefoot adduction with lateral subluxation of the navicular on the talus and heel valgus. Children present with pain, intractable callosities and abnormal shoe wear.

Non-operative treatment is rarely successful and with serial casting there is a danger of increasing the heel valgus [₁₀]. Surgical stabilization of the hind foot with heel cord lengthening and realignment of the bones of the forefoot are necessary [₁₁].