The limping child

A limp is a common reason for a child to present to the doctor.1 Because of the long list of potential diagnoses, some of which demand urgent treatment, an organised approach to evaluation is required. It is essential to understand the components of gait and the pathophysiology of specific abnormalities. Gait reflects the coordinated action of the lower extremities. The body moves forwards smoothly with economy of motion and energy. The stance phase (60% of the entire gait cycle) is the weight bearing portion.2 It is initiated by heel contact and ends with toe lift-off from the same foot. Swing phase is initiated with toe off and ends with heel strike. Limb advancement occurs during the swing phase (40% of normal gait cycle; fig 1). During this phase the foot pronates first and then supinates. Pronation shortens the foot, which helps it to clear the ground. Pronation also minimises the energy expenditure necessary for ground clearance as the non-weight bearing limb passes the weightbearing limb.2 Supination stabilises the bony architecture of the foot thus preparing it for heel strike, when the foot must absorb the shock of striking the ground. Table 1 shows the developmental progression of a child's gait, which should be incorporated into the assessment.