# A Systematic Review of Osteotomies to Correct Hallux Valgus in the First Metastasis
## 3 Results
### Distal Chevron Metastasis Osteotomy
#### 3.2.2 Follow-up and Biomechanical Analysis
Peak pressure, pressure time integral, and contact time all decreased post-surgically for the MT region. Contact area in the lateral toe (LT) region was increased post-surgically. Figure 7: Example of plantar pressure distribution with seven anatomical masks, obtained from an emed® platform (EMED-SF Pedography Analyzer (Novel GMBH, Munich, Germany): 1—heel; 2—MF; 3—LFF; 4—CFF; 5—medial forefoot; 6—MT; 7—toes. The participants were instructed to walk along a 10 m walkway at their natural pace, with data collection focused on the middle 6 m to minimize the impact of acceleration and deceleration. The average walking speed was determined based on the time recorded by photocells positioned along the 6 m data collection area. Each participant underwent two trials during each examination, with the second trial results used for analysis in all cases. All participants, including healthy individuals and patients, wore the same types of shoes (Klaveness Skofabrikk AS, Sandefjord, Norway) during the plantar pressure measurements. This shoe model was chosen due to its reputation for comfort and stability. It features a deep toe box providing ample space for the toes and wide shapes, allowing custom inside fitting. These shoes offered adequate cushioning and stability for the entire foot, ensuring consistent placement of the plantar structures on the insole sensors throughout the trials. Although slight variations were observed in pressure distribution between healthy participants' left and right feet, data from both feet were analyzed. Figure 5 represents the definitions of anatomical masks. The findings of this research [15,16] indicate that Chevron osteotomy appears to be effective in managing moderate hallux valgus deformity. It reduced pain levels during walking and maintained satisfactory joint mobility for 12 months post-surgically. According to these authors, no significant alterations were observed in various plantar load metrics (such as peak force, force-time integral, peak pressure, pressure-time integral, or contact time) for the MFF or MT regions. Although there were improvements in the initial plantar flexion of the metatarsopha-langeal joint after surgery, there was no noticeable enhancement in force generation in the MT region. The reasons behind the unchanged peak force despite decreases in peak pressure, pressure-time integral, and contact time are not readily explainable. Additionally, there were no changes in the contact area. However, these results suggest that the capacity for force production in the hallux and first MT may still be compromised even a year following surgery. The reduction in load related explicitly to the hallux region in this study can be attributed to two main factors. Firstly, surgical intervention may weaken the intrinsic musculoskeletal structures surrounding the first metatarsophalangeeal joint, altering the hallux's mechanical function. Similar levels of force-time integral, pressure-time integral, and contact time were observed both before and after surgery in the CFF region in this study. According to these findings, limited evidence suggests improvements in plantar loading variables 12 months post-surgery compared to pre-operative values. These changes in loading are unlikely to be attributed to variations in walking speed since contact time did not differ between pre-operative and post-operative conditions. The Chevron procedure may not significantly alter functional foot mechanics, as reflected in the outcomes of plantar loading. Instead, it might modify foot shape for cosmetic purposes and facilitate fitting into footwear. Further investigations are needed to assess plantar loading patterns following surgical correction for hallux valgus and verify if these observations remain consistent. These alterations in plantar loading appear unrelated to improvements in foot function.