Comparison of gait with and without ankle-foot orthoses after lower limb surgery in children with unilateral cerebral palsy

Abstract

Purpose: Children with spastic unilateral cerebral palsy (SUCP) frequently undergo lower limb surgery to improve gait. Postoperatively, ankle-foot orthoses (AFOs) are used to maintain the surgical corrections and provide adequate mechanical support. Our aim was to evaluate changes in gait and impacts of AFOs one-year postoperatively.

Methods: In all, 33 children with SUCP, 17 girls and 16 boys, mean age 9.2 years (5 to 16.5) were measured by 3D gait analysis walking barefoot preoperatively and walking barefoot and with AFOs one-year postoperatively. Changes in Gait Profile Scores (GPS), kinematic, kinetic and temporal spatial variables were examined using linear mixed models, with gender, gross motor function and AFO type as fixed effects.

Results: The results confirm significant gait improvements in the GPS, kinematics and kinetics walking barefoot one year after surgery. Comparing AFOs with barefoot walking postoperatively, there was additionally reduced ankle plantarflexion by an average of 5.1° and knee flexion by 4.7° at initial contact, enhanced ankle moments during loading response, increased velocity, longer steps and inhibited push-off power generation. Stance and swing phase dorsiflexion increased in children walking with hinged AFOs versus children walking with ground reaction AFOs. Changes in the non-affected limbs indicated less compensatory gait postoperatively.

Conclusion: Major changes were found between pre- and postoperative barefoot conditions. The main impact of AFOs was correction of residual drop foot and improved prepositioning for initial contact, which could be considered as indications for continued use after the one-year follow-up.

Level of evidence: Level II - Therapeutic.

Keywords: ankle-foot orthoses; gait; orthopaedic surgery; postoperative; unilateral cerebral palsy.

Fig. 1

The different types of ankle-foot orthoses (AFOs) used at the postoperative gait analysis: (a) hinged AFO with dorsal shell and foot part connected by integrated Tamarack flexure joints (Tamarack Habilitation Technologies Inc, Blaine, Washington); (b) polypropylene ground reaction AFO (GRAFO), with a ventral shell to mid-patella; as shown with shoes and standing alignment; (c) carbon composite GRAFOs with ventral shell to below patella.

Fig. 2

Movement analysis profile (MAP) with Gait Variable Scores (GVS) and Gait Profile Scores (GPS) in the three measurement conditions: preoperatively walking barefoot (PreBF), postoperatively walking barefoot (PostBF) and postoperatively walking with ankle-foot orthoses (PostAFO). Each column represents the root mean square difference across the gait cycle, averaged and with 1 sd for all participants (n = 33), with mean scores from our normal reference data (n = 24) in the darker base of each column (Ant, anterior; Pst, posterior; Flx, flexion; Ext, extension; Dor, dorsiflexion; Pla, plantarflexion; Dn, down; Add, adduction; Abd, abduction; Int, internal; Ext, external.

Fig. 3

Box-plots illustrating medians and interquartile ranges for all kinematic variables in the three conditions: preoperatively walking barefoot (PreBF), postoperatively walking barefoot (PostBF), postoperatively walking with ankle-foot orthoses (AFOs) (PostAFO) and clustered by AFO type: (a) ankle angle (°) at initial contact (IC), dorsiflexion (DF) positive and plantarflexion negative; (b) maximum (max) ankle DF (°) in 30% to 60% of the gait cycle (GC); (c) max ankle DF (°) in swing; (d) knee angle (°) at IC, knee flexion positive and knee extension negative; (e) minimum (min) knee flexion (°) in 30% to 60% GC; (f) min hip flexion (°) during GC (HAFO, hinged AFO; GRAFO, ground reaction AFO).