[Radiographic study of relationship between medial cuneiform obliquity and simple hallux valgus].

OBJECTIVE:To investigate the relationship between hallux valgus and the indicators associated with medial cuneiform obliquity measured on feet weight-bearing anteroposterior X-ray films. METHODS:Based on the feet weight-bearing anteroposterior X-ray films taken between January 2018 and February 2021 and met the criteria, the hallux valgus angle (HVA), intermetatarsal angle (IMA), metatarsus adductus angle (MAA), metatarsus cuneiform angle (MCA), distal medial cuneiform angle (DMCA), and proximal metatarsal articular angle (PMAA) were measured and the morphology of the first tarsometatarsal (TMT) were recorded. According to the HVA, the X-ray films were divided into normal group (HVA<15°) and hallux valgus group (HVA≥15°). The gender, age, sides, IMA, MAA, MCA, DMCA, PMAA, and the morphology of TMT were compared between groups. The influencing factors of HVA and IMA were analyzed by multivariate linear regression analysis. RESULTS:X-ray films of 534 patients (679 feet) met the selection criteria and were included in the study. There were 220 males and 314 females, with an average age of 36 years (mean, 18-82 years). There were 154 cases (168 feet) in the normal group and 403 cases (511 feet) in the hallux valgus group. There were significant differences in gender and age between groups ( P<0.05), and no significant difference in the side ( P>0.05). The IMA, MAA, and MCA in the hallux valgus group were significantly bigger than those in the normal group ( P<0.05); the difference in DMCA between the two groups was not significant ( P>0.05). The TMT morphology of the two groups was mainly curved, and the difference in morphology classification was not significant ( P>0.05). PMAA measurement showed that there were 3 kinds of metatarsal shapes: adductive metatarsal, neutral metatarsal, and abductive metatarsal, the difference in metatarsal shapes between groups was not significant ( P>0.05). The PMAA of abductive metatarsal was significantly bigger in normal group than in hallux valgus group ( P<0.05), there was no significant difference in PMAA of adductive metatarsal between groups ( P>0.05). Multivariate linear regression analysis showed that age, MCA, and DMCA were the influencing factors of HVA ( P<0.05), and age, MAA, MCA, and DMCA were the influencing factors of IMA ( P<0.05). CONCLUSION:The medial cuneiform obliquity is relatively constant and the DMCA can not be used as the characteristic angle to quantify hallux valgus. The morphology of TMT has no relationship with hallux valgus, while MAA, MCA, and PMAA are all factors to be considered, and MCA can be used as the characteristic angle to quantify hallux valgus.