General unobtrusive observation of the child walking and displaying the limp should be the first step. This will require the child to be undressed appropriately.

Remembering normal gait milestones is important. Children begin to walk independently from 12 to 14 months. This is preceded by crawling or “bum shuffling”, the latter of which may delay independent walking. ‘Stiff running’ may be observed from 16 months. Walking down steps (non-reciprocal) may be observed from 20 to 24 months, and walking up stairs using alternate feet from around 3 years. A mature gait is not usually reached until the age of 7, prior to which a toddler’s gait is observed. This consists of a wider base, often a toe to heel foot pattern and a much higher cadence. It may be that a limp cannot be readily appreciated in a slowly ambulating child and may only present itself when he or she walks much quicker or runs.

A systematic approach to the child’s gait should be adopted i.e. general cadence, stance and swing phases of each lower limb and then looking up from foot to trunk and back down.

The most common abnormal gait is an antalgic gait with the stance phase being shortened on the painful limb and a reciprocal longer stance phase on the unaffected side. In cases of back or “spinal” pain, a very slow and wary gait may be observed.

A Trendelenburg gait is observed when the abductors have limited function due to weakness, mechanical disadvantage, pain inhibition or a combination of all three. The pelvis is seen to tilt away from the affected side with a compensatory movement of the trunk towards the affected side. When no pain is present, the length of the stance phase is normal; often a Trendelenburg gait will only be seen when the child has walked for a longer period of time.

With proximal muscle weakness, the child will walk with an increased lumbar lordosis and will display Gower’s sign (climbing up their body using their hands) on getting up to walk. A spastic gait is most readily recognised when toe walking or scissoring is displayed; however many more subtle signs can be displayed dependent on the muscle groups affected. Again a longer period of observation and asking the child to walk faster may be the only way of revealing the abnormality. A short limb may be recognised from compensatory toe walking on the shortened limb and/or continued flexion of the longer limb at the hip and/or knee.

If the limp cannot be identified, then asking the child to hop with or without assistance may identify the affected limb. With children younger than 3 who usually cannot hop, lifting them up and down from a standing position will often lead to them not placing the affected limb down when landing.

The spine should be inspected for abnormal curvature, swelling, erythema and paraspinal spasm both in the standing and sitting positions. If the child is asked to pick something up from the floor and they have a painful back, they may do so by flexing at the hips and knees keeping their spine stiff and protected.