All you need to know about bow legs, knock knees, and flat feet in children

In our latest article, Mr Mark Latimer, esteemed Cambridge and Peterborough-based paediatric orthopaedic surgeon, explains exactly what bow legs and knock knees are, as well as outlining and describing the main causes of flat feet in children.

What are bow legs and knock knees, and what tends to be the main cause?

Children’s knees progress through fairly predictable changes in the angle between the tibia and the femur. Babies are born with bow legs, but by the time children get to reception class, they generally have knock knees.

By about the age of six, your child’s leg should have straightened out. If you sit your child in a chair and swing the legs together, the knees and ankle should touch at the same time. If the knees touch first, this is knock knees. If the ankles touch first, then this in bow legs.

There are more serious causes of malalignment at the knee such as Rickets or Blount disease. These should be excluded first.

If there is a more serious underlying cause, then the alignment of the legs can be very easily corrected using eight-plates as part of a day-case minor surgical procedure.

How common is flat feet in children?

Flat feet are incredibly common. In fact, 45 per cent of children will have no discernible arch in the first five years of life. In adolescence, this figure falls to about 15 per cent, and roughly this proportion of individuals will continue to have flat feet in adult life.

The vast majority of cases represent a normal variant with some possible underlying hypermobility. They require no formal treatment.

Can orthoses reduce pain in situations where children suffer from painful flat feet?

Orthoses do not change the shape of the foot but can reduce pain in painful flat feet.

What are the main causes of flat feet in children?

Most of the time, flat feet should be regarded as a normal variant. However, there are also some pathological causes of flat feet. Although it is very rare, and usually picked up at the ‘baby check’ (NIPE – Newborn Infant Physical Examination), a congenital vertical talus should be considered in a severe ‘rocker-bottom’ foot. More commonly, stiff flat feet may be caused by a tarsal coalition.

The most common coalition is calcaneo-navicular, which significantly improves following surgical excision. The second most common coalition is between the talus and calcaneum, and is within the subtalar joint. High-arched feet may be a normal variant, but an underlying neurological cause should always be considered.

What exactly is in-toeing and out-toeing?

Children tend to walk with an externally rotated foot progression angle. As they grow, the tibia rotates outwards. At the same time, the external rotation range in the hips reduces, but the internal rotation range does not increase to the same extent.

An abnormal rotational profile may result from torsion or rotational malalignment of the femur, the tibia, or indeed the foot itself.

Rotational alignment is best assessed by watching the child walk to note the foot progression angle. The child is then asked to lie prone with the knees bent. This allows assessment of both the foot thigh angle and the range of internal and external rotation in the hips.

Physiotherapy can be helpful in encouraging children to walk with a more normal foot progression angle. However, it will not alter the rotational profile of the long bones. This can only be achieved through a surgical derotation osteotomy. This is major surgery and is reserved for only extreme cases.

Most children with achy joints and hypermobility will achieve symptomatic relief from core stability exercises under the care of the physiotherapists. Specific joint problems related to hypermobility such as patellar or shoulder dislocations are also generally best treated by a physiotherapist.

Mr Mark Latimer is a highly proficient and experienced paediatric orthopaedic surgeon who specialises in knock knees in children. Consult with him today via his Top Doctors profile to book an appointment.