## 4 Discussion  
This study investigated the immediate effect of a customized FO designed with both medial longitudinal and transverse arch supports on the plantar pressure in patients with symptomatic hallux valgus. The results indicate that FOs significantly redistribute plantar pressure and contact area and enhance the functional support of the MF. A large population-based cohort study on hallux valgus and plantar pressure during gait reported lower center of pressure excursion indices and center of pressure excursion to foot width ratios in patients with hallux valgus [29]. Another study observed changes in plantar pressure in young female patients with hallux valgus during walking and found a decrease in lateral pressure, suggesting a tendency toward foot pronation [30]. Research sharing the purpose of the current study--to increase contact area and arch support to improve load distribution at the MF--has demonstrated that 3D-printed customized insoles may reduce the pressure on the metataralsals of patients with flatfoot [18; 31]. The peak force, press-time integral, and force-time integral of the MF increased considerably when the patients walked with the FO. These results are in agreement with previous findings indicating that an arch support insole can shift the load from the forefoot and rearfoot toward the MF [5; 32; 33; 34]. In the current study, we discovered that the force-time integral of the MF increased by 165% with the FO, a result consistent with another demonstrating a 144% increase in the force-time integral of the MF with customized insoles with medial arch support for patients with diabetes mellitus and associated neuropathic pain and foot deformities (including hallux valgus) [35]. Insoles with medial arch support can be used as an effective intervention to correct excessively high pressure in the forefoot area. Another study observed that customized insoles significantly reduced the peak pressure and pressure-time integral of the middle and lateral forefoot regions after 1 month of use [36]. The plantar pressure under the forefoot (metatarsal) area, however, exhibited no significant differences between the FO and FI conditions in the current study. This result may be due to the minor differences between the FI and FO; in the present study, the FI was composed of the same materials and 3 layers as the FO. The third layer was two-thirds length (around the transverse arch). This probably enhanced the support of the transverse arch by increasing the arch height [37]. In the current study, the peak pressure and pressure-time integral of the rearfoot (MH and LH) were substantially reduced when the patients wore FOs. Similarly, a study discovered that wearing customized insoles resulted in a considerable reduction in the peak pressure of the rearfoot, both immediately and at 1 month follow-up, in patients with hallux valgus [36]. Arch support insoles can also considerably reduce the average pressure and peak pressure of the rearfoot in patients with flatfoot [31; 32]. Studies have demonstrated that HVA is positively correlated with the pressure under the LH, and patients with hallux valgus exhibit greater pressure under the LH while walking than those without [30; 38]; therefore, redistributing plantar pressure and reducing the pressure under the rearfoot may be crucial in hallux valgus interventions. Regarding the plantar contact area, significant increases of 42.5% in the MF and 18.0% in the rearfoot were observed. Medial arch support orthotics can increase the plantar contact area of the MF and transfer forefoot pressure to the MF in patients with hallux valgus [4], but hallux valgus orthotics (braces) failed to more effectively distribute plantar pressure by increasing total contact area [39]. Furthermore, arch support insoles for flatfoot can increase the contact area of the MF [9; 18] and provide support for the medial arch, resulting in a more evenly distributed contact area of the MF, which may help absorb shocks during walking [40].