# A Systematic Review of Osteotomies to Correct Hallux Valgus in the First Metastasis  
[PERSON]  
1 University of Coimbra, Centre for Mechanical Engineering, Materials and Processes (CEMMPRE-ARISE), Department of Mechanical Engineering, 3030-788 Coimbra, Portugal; [EMAIL_ADDRESS]  
[PERSON]  
1 University of Coimbra, Centre for Mechanical Engineering, Materials and Processes (CEMMPRE-ARISE), Department of Mechanical Engineering, 3030-788 Coimbra, Portugal; [EMAIL_ADDRESS]  
[PERSON]  
2 Polytechnique Institute of Coimbra, Coimbra Institute of Engineering, 3030-199 Coimbra, Portugal; [EMAIL_ADDRESS]  
[PERSON]  
1 University of Coimbra, Centre for Mechanical Engineering, Materials and Processes (CEMMPRE-ARISE), Department of Mechanical Engineering, 3030-788 Coimbra, Portugal; [EMAIL_ADDRESS]  
Footnote 1: email: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Footnote 2: email: [[https://www.mdpi.com/journals/pdf](https://www.mdpi.com/journals/pdf)]([https://www.mdpi.com/journals/pdf](https://www.mdpi.com/journals/pdf))  
their feet extensively may not. This suggests that footwear may exacerbate an underlying skeletal abnormality rather than being the primary cause ([PERSON] et al., 2018; [PERSON] et al., 2018). The pathophysiology of HV is complex. However, it is generally believed that an imbalance exists between the extrinsic and intrinsic muscles of the foot, along with the involvement of the ligaments. The alignment of the first metatarsal is maintained by the tension exerted by the peroneus longus muscle laterally and the abductor hallucis muscle medially. Collateral ligaments function to restrict movement along the transverse plane at the first metatarsophalangeal (MTP) joint. If there is heightened pressure at the head of the first metatarsal, it will initiate medial-dorsal movement. This action increases the angle of the hallmark, which is further exacerbated by muscle stabilization during walking. As a result, these forces act to push the first metatarsal medially and the hallmark laterally, placing strain on the medial collateral ligament and the medial capsule, which can potentially lead to eventual rupture. In the absence of medial stabilizing structures, the lateral structures, such as the adductor hallucis muscle and collateral/lateral joint capsule ligaments, worsen this deformity ([PERSON] et al., 2018; [PERSON] et al., 2018). Figure 1 schematically shows the main factors that can lead to HVa. The first metatarsophalangeal joint (MTPJ) can become imbalanced, leading to the development of a deformity called hallux valgus, commonly known as a bunion. This condition can cause subluxation of the articular surface of the proximal phalanx over the head of the first MT, resulting in a visible bunion. To classify the severity of this deformity and help with surgical planning, healthcare professionals use two angles--hallux valgus angle (HVa) and intermetatarsal angle (IMA). These angles help to determine the severity of the deformity, which is classified as mild (HVa angles \(<30^{\circ}\) and IMa \(<13^{\circ}\)), moderate (HVa angles \(30\)-\(40^{\circ}\) and IMa \(13\)-\(20^{\circ}\)), or severe (with HVa \(>40^{\circ}\) and IMa \(>20^{\circ}\)). Radiographic measurement is used to analyze the deformity and anticipate the necessary impact of surgical intervention on hallux realignment, which is essential in selecting the appropriate procedure or combination of techniques ([PERSON] et al., 2018; [PERSON] et al., 2018). [PERSON] et al. (2018) presented a methodology to quantify the hallux valgus angle (HVA) used to measure the severity of the hallux valgus deformity. This methodology involves obtaining a 3D visualization of the foot and defining the highest and lowest points of the proximal and distal articular surfaces of the first metatatarsal (1 MT) (Figure 2). A longitudinal axis for the 1 MT is defined by drawing lines between the points.