Children with Cerebral Palsy: The impact of ankle-foot orthoses on gait function after lower limb surgery

Children with cerebral palsy (CP) often undergo orthopaedic lower limb surgery to correct malalignments, improve and maintain functional gait. In the post-operative period ankle-foot orthoses (AFOs) are used to support standing and walking, and to preserve the surgical corrections. In a cohort of ambulating children with bilateral (n=34) and unilateral (n=33) spastic CP we used three-dimensional (3D) gait analysis, and an observational, repeated measures design to evaluate impacts of AFOs on relevant gait variables one year postoperatively. We hypothesized that the children may have residual gait problems after surgery and that orthoses provide mechanical support to enhance gait. After surgery, major improvements included the gait profile score (GPS), kinematic and kinetic variables, whereas walking speed and step length declined. Walking with AFOs enhanced walking speed and step length. Children with bilateral CP showed further improvements in the GPS, stance ankle dorsiflexion and knee extension moments. Remaining crouch was reduced in children who used ground reaction AFOs (n=14). Multivariable regression analyses revealed that a high GPS, i.e. severe gait dysfunction preoperatively, was the strongest predictor of gait improvement walking with AFOs after surgery. Most children with unilateral CP had residual drop-foot walking barefoot postoperatively. Besides improved walking speed and step length, correction of drop-foot and improved prepositioning for initial contact at the ankle and knee were the main changes and indications for continued use of AFOs after the one-year postoperative follow-up. Curve and peak analysis of ground reaction forces indicated improved body-weight support and stance stability with AFOs. Clinicians and patients should be aware that prolonged use of orthoses may be necessary to reduce gait problems and avoid recurrence, particularly in children with remaining crouch or drop-foot postoperatively