Essential facts

Most books cover diseases, yet normal variants and normal developmental stages cause considerable anxiety to parents and doctors. Normal children have a rotational profile to their gait, as shown in Figure 24.1.

FIGURE 24.1 A child’s rotational profile.

(Adapted from Staheli LT (ed). Pediatric Orthopaedic Secrets, 2nd edn. Hanley and Belfus, Philadelphia; 2003.)

Gait variants

In-toe gait is seen in 14–18% of infants and is usually noted by the age of 2 years. The parents complain that the child in-toes and is clumsy. It is important to eliminate neurological causes (upper motor neurone lesions such as cerebral palsy exhibit increased muscle tone, upgoing plantar reflexes and sustained clonus) and to exclude in-toeing due to metatarsus varus of the feet or internal tibial torsion. Usually, in-toeing results from persistent femoral anteversion (PFA), as demonstrated by a greater range of internal than external rotation of the hip. PFA is often associated with generalized ligament laxity, which may explain both the clumsiness and the PFA. Lax ligaments cause inefficient proprioception (clumsiness) and produce less remodelling force on the femoral neck, which is anteverted 40° at birth but only 16° by age 16 years. Interventions do not alter the natural history; therefore, reassurance and explanation are important. These children commonly sit splay-legged in the W shape, but should be dissuaded as this may exacerbate PFA and cause external tibial torsion deformities. Most children improve with age under peer pressure, but all will continue to in-toe with inattention or when tired.

Out-toeing gait is usually noted as the child starts to walk. Fetal moulding from compression by the uterus before birth produces hip flexion and external rotation contractures, such that all children initially walk out-toed with their hips and knees flexed. These contractures stretch out by age 2 years, sometimes to reveal an in-toed gait from PFA.

Bow legs and knock-knees

All children are bow-legged (genu vara) until age 2 when they become knock-kneed (genu valga). Genu vara appears greater in a child who in-toes. Genu valga is maximal between ages 3 and 4 years, and may be more marked in children who have ligament laxity or are overweight. The adult alignment of slight valgus is usually achieved by age 9 (Fig. 24.2). Bow legs beyond age years or knock-knees before 18 months are probably pathological, in which case rickets or an inherited skeletal dysplasia that can cause either genu vara or valga should be excluded. Persisting bow legs in a heavy early walker may be due to Blount’s disease (medial growth delay or arrest of the proximal tibial physis). This condition is more common in African Caribbeans. If detected early, it can readily be corrected surgically by a medial periosteal release. If detected late, complex osteotomies are required to correct this tri-planar deformity.

FIGURE 24.2 Calcaneo-valgus at birth. The ankle is excessively dorsiflexed and the foot is deviated away from the midline (valgus)