Functional assessment in patients operated for abnormal pronation syndrome: a pre-post intervention study protocol

L. Pedrotti,^1,2 P. Patanè,^3,4 M. Chiodaroli,^1,5 N. Carlone,⁵ D. Borsatti,⁶ L. Marin^1,3-5 | ¹Laboratory for Rehabilitation and Orthopedic Surgery, Department of Clinical Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Italy; ²Department of Pediatric Diagnostic Surgical Clinical Science, Section of Pathologies of the Musculoskeletal System, Orthopedics Unit, University of Pavia, Italy; ³Department of Rehabilitation and Sports Medicine, Faculty of Medicine, University of Ostrava, Czech Republic; ⁴Laboratory of Adapted Motor Activity, Department of Public Health, Experimental Medicine and Forensic Science, University of Pavia, Italy; ⁵Department of Rehabilitation, “Città di Pavia” Healthcare Institute, Pavia, Italy; ⁶Degree Course in Medicine and Surgery, Faculty of Medicine and Surgery, University of Pavia, Italy

Pediatric flatfoot is characterized by excessive subtalar joint pronation, medial longitudinal arch collapse, and hindfoot valgus. Subtalar arthroereisis represents the most common surgical treatment for symptomatic cases. Traditional post-operative evaluations rely on radiographic parameters and subjective clinical scales like the American Orthopaedic Foot and Ankle Society's ankle-hindfoot scale (AOFAS-AHS), which may not correlate with functional recovery. The primary aim of this study will be to evaluate post-operative modifications in gait dynamics in flatfoot patients undergoing subtalar arthroereisis, possibly associated with accessory procedures. Additionally, correlations between baropodometric data and variations in subjective parameters and radiographic angles will be investigated. A pre-post intervention study will be conducted on patients aged 10-18 years undergoing subtalar arthroereisis. Evaluations will include AOFAS-AHS score, weight-bearing radiographs, and dynamic baropodometry, using the Freemed Dynamic stabilometric platform (Sensor Medica, Guidonia Montecelio, Rome, Italy), at pre-operative (T0) and 6-month post-operative (T1) timepoints. Baropodometric parameters will include total contact surface, hallux contact area and load percentage, step duration, and spatiotemporal variables. The analysis will focus on outcome values provided by clinical, radiographic, and baropodometric assessments, comparing T0 and T1 timepoints. Correlations between baropodometric data and radiographic/clinical parameters will be evaluated using the Spearman correlation coefficient. Based on current literature evidence, improvements are anticipated in AOFAS-AHS scores and normalization of radiographic angles. Baropodometric analysis is expected to show a reduction in total foot contact surface, decreased hallux loading, and improved temporal gait parameters, reflecting correction of abnormal pronation patterns consistent with previous studies. This study will demonstrate whether subtalar arthroereisis effectively corrects functional gait alterations alongside anatomical deformities. Dynamic baropodometry may provide an objective functional assessment complementary to traditional evaluations, potentially justifying its clinical implementation for comprehensive outcome evaluation.