Influence of equinus treatments on the vertical displacement of the body's centre of mass in children with cerebral palsy.

We assessed the influence of equinus gait treatments on the vertical displacement of the body's centre of mass (COM) in 21 patients with cerebral palsy (14 males, 7 females; mean age 8 y 9 mo [SD 2 y]; range 3 y 7 mo-17 y) presenting different topographical types (quadriplegia, n = 1; diplegia, n = 6; right hemiplegia, n = 6; and left hemiplegia, n = 8). Vertical COM displacement was computed from ground reaction forces, and lower limb kinematics was recorded simultaneously. Equinus gait was treated with non-operative treatments (i.e. botulinum toxin injections and stretching casts) in 14 patients, and with operative treatments in seven patients. After non-operative treatments, the entire ankle displacement shifted towards dorsiflexion throughout the gait cycle, but the amplitude of the third foot rocker (TR) and vertical COM displacement remained unchanged. However, after operative treatments, the amplitude of TR increased and vertical COM displacement decreased. A negative linear correlation was found between the former variables in all the patients where 53% of the changes in their vertical COM displacement, after equinus gait treatments, were explained by the changes in TR amplitude. In fact, TR remains a main gait determinant, reducing the vertical COM displacement after equinus gait treatment and influencing the general gait pattern.