Reduced ipsilateral pre-operative forefoot pressure during gait is associated with poorer post-operative postural control in people with chronic ankle instability

Residual postural instability following the modified Broström procedure for chronic ankle instability (CAI) remains a clinical challenge. Current preoperative assessments emphasize structural and demographic factors, neglecting dynamic biomechanical aspects which may better predict functional recovery. This study investigated whether preoperative plantar pressure distribution and gait parameters are associated with early postoperative postural control. A total of fifty-five CAI patients (age, 19 to 40 years) scheduled for a modified Broström procedure underwent smartphone-based gait evaluation before surgery. At three months postoperatively, participants were stratified into stable ( n = 28) or unstable ( n = 27) groups based on the ability to maintain a single-leg stance for 10 s with eyes open. Preoperative temporal-spatial gait parameters and regional plantar pressure distributions were compared between group. Linear regression model and ROC curve analysis were used to identify predictors of post-operative instability. The unstable group exhibited significantly lower preoperative peak pressure under the ipsilateral fifth metatarsal head ( p = 0.042), toes ( p = 0.026), and forefoot ( p = 0.019), alongside prolonged bilateral step duration and contralateral stance duration. A model containing contralateral stance duration and ipsilateral forefoot peak pressure significantly predicted group allocation. A forefoot pressure below 40 kPa predicted postoperative instability with 84.3% sensitivity and 61.1% specificity. Preoperative ipsilateral forefoot loading reductions and prolonged step duration are associated with early postural instability after modified Brostrom procedure. These gait alternations may serve as potential biomarkers for risk stratification, informing the development of targeted prehabilitation protocols to optimize postoperative outcomes. Chinese Clinical Trial Registration, ChiCTR2100046146. May 5th 2021.