Gait Posture. 2025 Oct 14;124:110010. doi: 10.1016/j.gaitpost.2025.110010. Online ahead of print.
ABSTRACT
BACKGROUND: Gastrocsoleus lengthening (GSL) is an established surgical intervention for equinus deformity in children with cerebral palsy (CP). While GSL typically improves ankle function during stance, some children experience persistent ankle plantar flexion during swing, known as foot drop. The etiology and key indicators for post-GSL foot drop are not fully understood. This study aimed to (1) predict foot drop following GSL using pre-operative gait and clinical data and (2) identify associated risk factors of foot drop.
METHODS: One-hundred and ten children with CP (36 with hemiplegia, 74 with diplegia) were recruited. Physical examinations and three-dimensional gait analysis of barefoot walking were conducted pre- and post-operatively. A deep learning model, incorporating convolutional and feed-forward neural networks, was developed to predict post-operative ankle dorsiflexion using both pre-operative clinical and gait data. Shapley Additive exPlanations (SHAP) and logistic regression were used to assess associations between pre-operative gait and clinical variables and post-operative foot drop.
RESULTS: Ankle dorsiflexion during a full gait cycle was predicted with an RMS difference of 5.1° relative to measured joint angles, and post-operative foot drop classified with 87% accuracy. Soleus muscle length, maximum dorsiflexion during mid-swing, CP topography, and ankle gait variable score (GVS) were the greatest determinants of foot drop, exhibiting the highest SHAP values (0.40, 0.32, 0.17, and 0.15 respectively) and strongest correlation with post-operative foot drop (β: -0.74, -0.87, 0.37, and 0.59, respectively) (p < 0.05).
SIGNIFICANCE: Accurate predictions of post-GSL dorsiflexion and foot drop risk can be achieved using pre-operative gait and clinical assessment. Several features, including pre-operative dorsiflexion during mid-swing, soleus muscle length, and ankle GVS, were identified as significant contributors to persistent foot drop. The findings may be useful in surgical planning for equinus deformities.
PMID:41223483 | DOI:10.1016/j.gaitpost.2025.110010
