Abstract: BACKGROUND: Pediatric flexible flatfoot is a common foot deformity that often leads to foot pain and reduced quality of life. 
OBJECTIVE: To explore the relationship between radiographic parameters and clinical efficacy of subtalar arthroereisis in the treatment of pediatric flexible flatfoot.
METHODS: A retrospective study was conducted on 56 pediatric patients (mean age of 11.8 years) who underwent subtalar arthroereisis at Guangzhou Orthopedic Hospital between January 2022 and May 2023. All patients underwent detailed radiographic examinations and clinical evaluations before and after surgery, including the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot score and Visual Analog Scale score. Paired t-tests and independent t-tests were used to compare changes in radiographic parameters and clinical scores before and after surgery. Correlation analyses were conducted to evaluate the relationship between radiographic parameters and clinical outcomes. 
RESULTS AND CONCLUSION: (1) All radiographic parameters significantly improved during the 8 to 12-month follow-up after surgery (P < 0.001). (2) Clinical evaluation results indicated that the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot score significantly improved from 66.2±6.0 preoperatively to 91.3±5.8 postoperatively, and the Visual Analog Scale score significantly decreased from 3.1±0.8 preoperatively to 1.3±0.8 postoperatively (P < 0.001). (3) Independent t-tests showed a significant difference in postoperative the first metatarsal angle and Visual Analog Scale score grades (P=0.043), with a smaller the first metatarsal angle associated with less postoperative pain; preoperative lateral arch angle showed a significant difference between the “excellent” and “good” groups in postoperative American Orthopaedic Foot & Ankle Society Ankle-Hindfoot scores (P=0.033), suggesting that a smaller preoperative posterior arch angle might predict better postoperative foot function recovery. (4) Correlation analysis showed that preoperative posterior arch angle (r=-0.486, P < 0.01) and heel pitch angle (r=-0.344, P < 0.01) were significantly negatively correlated with postoperative American Orthopaedic Foot & Ankle Society Ankle-Hindfoot, while preoperative medial longitudinal arch angle (r=0.293, P < 0.05) was significantly positively correlated with postoperative American Orthopaedic Foot & Ankle Society Ankle-Hindfoot. Postoperative medial longitudinal arch angle (r=0.331, P < 0.05) and lateral arch angle (r=0.387, 
P < 0.01) were significantly positively correlated with postoperative American Orthopaedic Foot & Ankle Society Ankle-Hindfoot, whereas postoperative Bohler's angle (r=-0.272, P < 0.05), posterior arch angle (r=-0.461, P < 0.01), and heel pitch angle (r=-0.318, P < 0.01) were significantly negatively correlated with postoperative American Orthopaedic Foot & Ankle Society Ankle-Hindfoot. (5) It is concluded that subtalar arthroereisis is significantly effective in correcting pediatric flexible flatfoot, and improvements in radiographic parameters are closely related to clinical efficacy. Preoperative and postoperative radiographic evaluations can serve as important reference indicators for predicting postoperative clinical outcomes, guiding clinicians to optimize treatment plans and rehabilitation programs. 

Key words: flexible flatfoot, subtalar arthroereisis, clinical efficacy, correlation analysis, postoperative rehabilitation, children, radiographic indicators, orthopedic implant