Objective: To explore the application value of 3D scanning to obtain the parameters of transverse axis of medial longitudinal arch of foot in the biomechanical evaluation of transverse axis of medial longitudinal arch of foot in children.Method: The feet of children with flat foot, normal foot and high arched foot were scanned with the Foot Secret 3D scanner in the sitting and standing positions. The scanning data were imported into CATIA v5 software for measurement, to obtain four parameters of transverse axis of medial longitudinal arch from transverse arch angle, external transverse arch angle, curvature and transverse arch cross-sectional area.Result: There were statistically significant difference in transverse arch angle, external transverse arch angle and cross-sectional area between sitting and standing positions (p < 0.05). There were statistically significant differences in transverse arch angle, external transverse arch angle, curvature and transverse arch cross-sectional area among children with flat foot, normal foot and high arch foot (p < 0.05).Conclusion: The four parameters of transverse arch angle, external transverse arch angle, maximum curvature and cross-sectional area obtained by three-dimensional scanning can detect the changes of transverse axis of children's foot arch in different body positions with different foot types, which can be effectively used for the biomechanical evaluation of transverse axis of children's foot arch.

Objective: To investigate clinical application of day surgery A1 pulley release for pediatric trigger thumb.Methods: We retrospectively analyzed the clinical data of 1,642 children with trigger thumb who were treated with day surgery A1 pulley release at our hospital, including satisfaction surveys, functional recovery, and complications.Results: The operative time for unilateral and bilateral tenolysis was 4.8 ± 3.1 and 9.2 ± 3.8 min, respectively. Three children had postoperative fever and were discharged on the 2nd day after surgery. The rest of the children were discharged on the day of surgery. All incisions healed primarily, and no complications of vascular and nerve injury were reported. The patients' degree of satisfaction with the medical treatment process, diagnosis and treatment workflow, treatment effectiveness, length of hospital stay and hospitalization cost, and discharge guidance were 97.9, 96.1, 99.3, 91.1, and 98.5%, respectively. The follow-up period was between 5 months and 3 years and 1 month. Four children experienced symptom relapse after the operation, and re-tenolysis was performed in one of them. At the final follow-up, the appearance and function of the thumb had recovered well in all cases.Conclusion: Day surgery A1 pulley release can effectively release tendon sheaths and has a short operative time, no complications of vascular and nerve injury, and good recovery of thumb function. It is a safe and reliable procedure with high patient satisfaction, and it is worthy of clinical promotion.