Abstract: BACKGROUND: At present, the osteotomy is the mainstream surgical method, and there are many complications. Elastic fixation between the first and second metatarsals is a new surgical method for hallux valgus.  
OBJECTIVE: Using the method of finite element analysis, the treatment of hallux valgus with fixation between the first and second metatarsals was studied, which provided theoretical data for clinical treatment.
METHODS:  CT data of a female patient with hallux valgus in Changzhou Tumor Hospital Affiliated to Soochow University were collected to establish a finite element model of hallux valgus. Three surgical sites were divided into group A (from the base of the distal first metatarsal to the base of the distal second metatarsal); group B (from the base of the distal first metatarsal to the middle segment of the second metatarsal); group C (from the base of the distal segment of the first metatarsal to the base of the proximal segment of the second metatarsal). The first metatarsal and the second metatarsal were fixed respectively to correct the hallux valgus angle to 9 degrees in the three groups to analyze stress and deformation after fixation. The protocol was conducted in accordance with relevant ethical requirements of Changzhou Tumor Hospital (approval No. 2019-SY-031; date: 2019). Patients and their family signed the informed consent.  
RESULTS AND CONCLUSION: (1) After implementing the surgical plan at the three groups of surgical sites, in group A, the total foot stress was 202.43 MPa, and the deformation was 1.71 mm; the first metatarsal stress was 37.38 MPa, and the deformation was 1.71 mm; the second metatarsal stress was 1.16 MPa, and the deformation was 0.005 mm. In group B, the stress of the whole foot was 220.58 MPa, and the deformation was 1.47 mm; the first metatarsal stress was 29.26 MPa, and the deformation was 1.47 mm; the second metatarsal stress was 0.94 MPa, and the deformation was 0.004 5 mm. In group C, the total foot stress was 141.94 MPa, and the deformation was 1.07 mm; the first metatarsal stress was 23.62 MPa, and the deformation was 1.07 mm; the second metatarsal stress was 1.43 MPa, and the deformation was 0.003 2 mm. (2) The results showed that the surgical site from the base of the distal first metatarsal to the base of the distal second metatarsal or the middle segment of the second metatarsal had higher deformation ability, which was more conducive to the correction of hallux valgus angle.

Key words: hallux valgus, elastic fixation between metatarsals, osteotomy, finite element analysis ,