Objective: This study aimed to assess the effects of customized orthoses on foot morphology and plantar pressure in professional athletes with accessory navicular syndrome (ANS) over a 12-month period, compared to conventional insoles. Methods: In this randomized controlled study, 54 pro athletes with medial foot pain, diagnosed with ANS, joined after 3-month training. Split into two groups: custom orthotics (intervention) or regular insoles (control). Evaluated at 3, 6, 12 months on foot structure (arch, navicular, etc.) and function (pressure, force-time integral, VAS pain). Found significant improvements in intervention group's foot shape, pressure distribution, and pain reduction compared to controls. Results: Compared to the control group, the intervention group showed significant increases in arch angle and arch height across all assessment intervals (P < 0.05). Additionally, heel eversion angle and navicular prominence distance significantly decreased in the intervention group compared to controls (P < 0.05). Pressure and force-time integral values at the first metatarsal head, medial arch, and medial heel significantly decreased, while lateral arch loading increased in the intervention group (P < 0.05). VAS scores for foot pain significantly decreased in the intervention group compared to controls (P < 0.05). Conclusions: Customized orthoses effectively improved foot morphology and reduced plantar pressure in professional athletes with ANS compared to conventional insoles. These findings suggest that customized orthotic intervention provides faster and more significant pain relief for patients with ANS-related medial arch collapse.

Background: Chinese Clinical Trial Registry (ChiCTR2500100238; Retrospectively registered on 04/07/2025).