(a) Jack’s windup test. (b) Arch restoration on passive dorsiflexion of the big toe. (c) Arches reformed on heel rise and heels swing into normal varus
Standing on Tiptoes
Make the child to stand on his or her toes and observe the feet from behind. As soon as the child rises onto the toes, the heel swings into varus and the arches are formed (see Fig. 16.1c).
When both these tests restore the arches, the foot is diagnosed to have a physiological flatfoot. When the arches do not restore, the flatfoot is rigid or pathological.
Flatfeet (Pes Planus)
Complaints about the appearance of the foot are common in a pediatric practice. In India, feet remain exposed for most of the day-to-day life. Therefore, esthetics of the foot has a lot of importance to parents. Among the various complaints that the parents bring, complaints about the child being flat-footed are the most frequent.
A flatfoot is characterized by the lack of a medial arch. However, the absence of the arch may be normal; the arch is absent in most urban children till the age of 3 years and often does not form well till the age of 6 years . After the age of 6 years, weight-bearing pattern of the foot becomes similar to that of an adult. The lack of this medial arch is often accompanied by ligamentous laxity. In older children, genu valgum (knock-knee) and obesity may also be associated.
There are essentially two types of flatfoot – hypermobile and rigid flatfoot (see Table 16.1).
Causes of flatfoot
Flatfoot associated with generalized ligamentous laxity: Marfan’s, Ehlers-Danlos syndrome, Down’s syndrome, Rubinstein-Taybi syndrome
Congenital flatfoot (congenital vertical talus)
Neuromuscular pes planus
Tibialis posterior deficiency
It is important for the clinician to distinguish between the various types:
Physiological flatfoot is by far the most common of all types: It is typically seen in children of walking age. The feet otherwise appear normal except for a nonvisualization of the medial planter arch. The Jack’s windup test and standing on tip toes restore the arches (see above).
The hypermobile flatfoot (flexible flatfoot) is a more severe entity than a physiological flatfoot. It is characterized by absent arches and normal or excessive subtalar motion on clinical testing. The whole foot appears hyperpronated. In some cases, the hyperpronation is so extreme that the lateral border of the foot loses contact with the ground and does not take part in weight bearing. The talus may protrude medially. The heel is seen to have a prominent valgus. In severe cases, tendo Achilles contracture will be present. The Jack’s test may or may not restore the medial arch. Usually, standing on tiptoes restores the arch or improves it (see Fig. 16.2a, b). Tests for general hyperlaxity may be positive. Shoes of the child will show uneven inside wear.
(a) Left-sided hypermobile flatfoot. Note the pronated foot, valgus forefoot. (b) Left foot – note the prominent heel valgus. Lateral border has minimal contact with the floor
X-ray of the feet lateral standing and AP views standing show increased talocalcaneal angles with increased obliquity of the talus (see Fig. 16.3a, b).
(a) Hypermobile flatfeet. AP standing both feet showing increased AP talocalcaneal angle. Talus points medially. (b) Lateral view standing. Talus points down and lateral talocalcaneal angle is increased
The Rigid Flatfoot
Congenital Vertical Talus/Congenital Flatfoot
A congenital rigid flatfoot is clearly evident at birth. The foot is boat shaped, with the talar head occupying the most prominent position of the convexity of the sole. The heel is in equinus and the tendo Achilles is severely contracted. The forefoot is pushed into dorsiflexion and valgus. There is marked rigidity of the foot, and it cannot be passively manipulated into correction. In orthopedic circles, this condition is called the congenital vertical talus and a rocker bottom foot. A radiograph of the foot will reveal all the features of a vertical talus in varying degrees – the talus is abnormally positioned vertically – it points medially and downward. The calcaneum is also in equinus with a prominent heel cord contracture. The foot appears to have reversed the arch that is now convexed downward. The navicular and the rest of the forefoot are placed dorsally and laterally in relation to the talar head (see Fig. 16.4a–e).
(a) Radiograph lateral and AP right foot of 10-month-old male with congenital vertical talus. The talus is almost vertical. The calcaneum is in equinus too (see calcaneal axis with respect to the sole). The axis of the first metatarsal reveals a midfoot break. This deformity cannot be corrected passively. (b) X-ray right foot AP – CVT AP view of the same patient showing large talocalcaneal divergence and the talus pointing far medially. In a normal foot, the first metatarsal axis lines up with the talar axis both in AP and lateral. Here, there is a break (midfoot break). (c) Same child 5 months postoperatively showing complete restoration of normal anatomy on lateral view. (d) AP view showing restoration of normal anatomy. (e) Clinical appearance 5 months post-op (same patient as above) – excellent appearance, well-formed medial arch
The other type of rigid flatfoot is that found in tarsal coalition. As the name suggests, there is an abnormal connection (fibro-osseous or osseous) between the various tarsal bones of the foot. The condition is present at birth, but the child presents with symptoms at 8–16 years of age. The predominant symptom is pain. The cause of pain is not proven and may result from normal weight-bearing stresses across an incompletely fused fibro-osseous coalition mass. Pain is localized to the hindfoot and induces a spasm of the peroneal muscles. Sports activities or even walking on uneven ground brings on the pain. The patient may have also noticed a flatfoot or an external rotation of the foot or foot stiffness.
Clinical examination reveals a flatfoot of a varying degree. Occasionally, arches may be normal. The main finding is an absence of subtalar motion – passive inversion or eversion of the heel reveals very little or no mobility. On occasion, this manipulation may elicit pain. Standing on tiptoes does not restore the arch. Jack’s test is also unable to create an arch.
The most common coalitions are between the calcaneus and talus and between the calcaneus and navicular. Other combinations may exist. These coalitions may also be found in conditions like fibular hemimelia and Apert’s syndrome. Radiographs may or may not show up the coalition. The most commonly diagnosed coalition on a plain radiograph is the calcaneonavicular bar. Other coalitions usually require a CT scan to clinch the diagnosis. The CT scan also picks up coexisting coalitions elsewhere in the tarsal complex.
It is most important to differentiate a physiological hypermobile flatfoot from a pathological or a rigid flatfoot. The treatment of a rigid flatfoot at birth needs orthopedic intervention in the first month of life. At this early stage in life, orthopedic intervention consists of serial casting followed by minimally invasive surgery or a limited surgery. Good long-term results are obtainable by these newer techniques with maintenance of good foot form, mobility, and function. When detected at a later stage, extensive surgery is required.
By contrast, the initial treatment of tarsal coalition is always conservative. Initial treatment starts with a foot orthosis to reduce inversion and eversion stress on the hindfoot and thereby relieves pain. Children who do not respond to orthotic management may respond to a 6-week immobilization in a cast, followed by orthotic support. Often, the relief is long lasting with the child requiring no further treatment. Children who complain of repeated episodes of pain may be candidates for surgery. Small limited areas of coalition are treated by excision of coalition and interposition of the muscle or fascia or tendon graft so as not to allow the fusion to reform. This approach has a success rate of 80–90 % . Failure of treatment is considered if the pain returns. Children who fail resection surgery or who are symptomatic with large coalitions and large heel valgus may be treated by fusion surgery.
Mobile flatfeet are physiological at 3–7 years of age. They represent a variant of normal feet and need no special treatment. Their natural history is one of gradual improvement over the first eight years of life. Orthotic soles and specialized footwear do not improve the natural history of this condition . Shoe wear may actually be detrimental for the development of good arches . Therefore, the advice for these children is to maximize barefoot walking – especially in sand and grass. Tiptoe walking as exercise is also recommended. These activities improve the muscle tone and strength in the feet and calf – thereby improving the development of plantar arches.
One must bear in mind that hypermobile flatfoot is a spectrum disorder. The children who fail to improve over a period of observation, who have pronated feet with tight heel cords and medial border weight bearing, are diagnosed as hypermobile flatfoot. The more severe forms may require early childhood interventions with casting, followed by orthotics combined with foot muscle exercises. Surgery, if required, is carried out after 9 years of age and consists of osteotomy to lengthen the calcaneum, combined with soft tissue procedures .
An eight–year–old female was seen in the clinic with complaints of abnormal walking and a progressive deformity of her knees since the age of 4 years. Her father had a similar problem for which he had been operated at the age of 20 years. She had undergone previous treatment including brace application and vitamin D oral therapy. Clinical examination showed her to be of normal height and weight. General physical examination (GPE) was normal apart from an obvious deformity of the knees. Local examination showed her to have severe bilateral genu valgum. She was not able to walk with her feet straightforward and instead walked with significant external rotation of her legs. Her standing intermalleolar distance was 21 cm. Her torsional profile was normal. She was within the 25th percentile for height (see Fig. 16.6a).
What is your impression? How would you establish a diagnosis?
At this point, you know that this is an 8–year-old female child who has severe genu valgum. As per the history, this is progressive. Her x–ray for both knees AP view (6b) shows a severe deformity with bowing of the shaft of the femur, physes of normal height, but deformed epiphyses. Her blood tests including complete blood count (CBC), renal function tests, venous blood gas, serum Parathyroid hormone (PTH), and vitamin D3 and alkaline phosphatase are completely normal. US abdomen and urine routine are normal.
Examination of her father shows him to have a bilateral genu valgum and early osteoarthritis with crepitus on movement and pain on terminal flexion and extension. His flexion range is restricted.
What is your diagnosis and plan of treatment?
This child has a severe genu valgum. This may be due to a focal familial epiphyseal dysplasia. It is obvious that this cannot be managed by observation or splintage. This case needs an urgent orthopedic referral (see Fig. 16.6c, d).
Genu Varum (Bowlegs) and Genu Valgum (Knock-Knees)
Deformities of the knee are among the most common abnormalities to affect the pediatric lower extremity. A majority of these deformities are physiological and will resolve spontaneously. A small number may be progressive and will need appropriate diagnosis and referral in order to be correctly treated.
The legs in a newborn are usually bowed. They show 10–15° of varus angulation. This condition is named physiological genu varum. The deformity is fairly evident from the gap that appears between the knees as the legs are held out straight (hence the name “bowlegs”). The varus tends to get even worse as the infant begins to stand. Tibial intorsion, an inward twisting of the tibia, is associated with genu varum, and it tends to make the deformity look worse. Parents usually seek medical advice for bowleg at 1–2 years of age. On clinical examination, the child shows a medial bowing of the legs that is bilateral and symmetrical. When measured, the angle between the thigh (femur) and the leg (tibia) measures at least 10° at the knee . If a radiograph is taken, the growth plates around the knee are always normal (see Fig. 16.5a, b).
(a) Physiological genu valgum in boy aged 3 years 6 months. (b) Radiograph of the same child showing normal appearance of physes
The natural history of physiological genu varum is one of the gradual age-dependent resolutions: Heath and Staheli (1993)  analyzed the deformities of the knees in young children. They measured the intercondylar distance at the knee to assess genu varum and intermalleolar distance at the ankle to assess genu valgum. They found the genu varum to be maximum at 6–12 months of age, and this recovered by 18–24 months. After this time, they found the knee to angulate into valgus creating the maximum genu valgum at 4 years of age. The knee angles finally settled to an average adult value of 6° by 8–11 years . Published data from India reflects a similar trend .
In some children, the knee deformity may not follow the expected pattern of age-related change and eventual resolution. Progressive genu varum is seen in physes that are pathological. Examples are Blount’s disease, hereditary multiple exostoses, multiple epiphyseal dysplasia, rickets from various causes, and following infections and trauma.
Rarely, genu varum results from an abrupt varus at metaphyseo-diaphyseal junction without any physeal involvement. This condition is labeled as focal fibrocartilaginous dysplasia. The cause is unknown, and it improves spontaneously in a majority of cases.
Progressive genu valgum is also seen similarly in various conditions where the physes are pathological (see Table 16.2). Large degrees of genu valgum are associated with obesity, even though the physes may appear normal.
Causes of knee deformity
Genu varum of infancy
Multiple epiphyseal dysplasia/metaphyseal dysplasia
Focal fibrocartilaginous dysplasia
Physiological genu valgum
Trauma, Cozen’s fracture/infection
Hereditary multiple exostosis
Multiple epiphyseal dysplasia/metaphyseal dysplasia
In our clinic, the assessment of a child with knee deformity consists of a careful history taking, a general physical examination, and a local examination. The local examination includes measurement of the standing intercondylar distance in genu varum and standing intermalleolar distance in genu valgum. This is done by standing up the child on a hard surface with the parent supporting the trunk for balance. In genu varum, the legs are gently brought together till the ankles touch. A measurement is taken of the distance between the medial femoral condyles for intercondylar distance. Similarly, in genu valgum deformity, the knees are gently but firmly brought together. The distance between medial malleoli is then measured carefully and documented as intermalleolar distance. Where rickets is suspected, a serum measurement of vitamin D level, alkaline phosphatase, calcium, and phosphate levels is done. A radiograph of both knees AP view is carried out as well.