IntroductionPrevious observational studies have reported that thyroid dysfunction is associated with hallux valgus (HV). However, the causal effect of thyroid dysfunction on hallux valgus is still unknown. To assess whether there is a causal relationship between thyroid dysfunction and hallux valgus, we performed a two-sample Mendelian randomization (MR) study.MethodsThe data of the two-sample Mendelian randomization study were obtained from public databases. In this study, hypothyroidism, hyperthyroidism, free thyroxine (FT4), and thyrotropin (TSH) were chosen as exposures. The single nucleotide polymorphisms (SNP) of hypothyroidism and hyperthyroidism were from the genome-wide association studies (GWAS) of the IEU database, including 337,159 subjects. Data for FT4 and TSH (72,167 subjects) were extracted from the ThyroidOmics Consortium. HV was used as the outcome. The SNPs associated with HV were selected from a GWAS of 202,617 individuals in the fignngen database. The inverse variance weighted (IVW) method was used as the primary analysis. Four complementary methods were applied, including MR-presso, MR-Egger, and weighted median. In addition, Cochran’s Q test, MR-presso, MR-Egger regression, and the leave-one-out test were used as sensitivity analysis, and the MR-pleiotropy test was performed to examine pleiotropy.ResultsAccording to the results of IVW, we found that there was a causal relationship between hypothyroidism and HV, and hypothyroidism increased the incidence of HV (OR = 2.838 (95% CI: 1.116–7.213); p = 0.028). There were no significant causal effects of hyperthyroidism, FT4, and TSH on HV (p > 0.05). Sensitivity analyses showed that the results were robust and reliable, and no horizontal pleiotropy was detected.ConclusionsOur findings provided genetic support that hypothyroidism might increase the risk of HV. It will predict the occurrence of HV in patients with hypothyroidism and provide suggestions for early prevention and intervention.

Objective To investigate the quantitative correlation between the osteotomy end displacement and the occurrence of transfer metatarsalgia in percutaneous minimal invasion surgery of bunion in the forefoot loading pattern.Methods The simulation of the operation of minimally invasive treatment of hallux valgus using the established finite element model with the period of forefoot load mode facilitated the correction of the distal end of the first metatarsal head after osteotomy by steps of 0–6 mm from inside to outside and from top to bottom; each displacement distance was 2 mm. The stress data were collected and analyzed at the osteotomy end and under each metatarsal head in the gait cycle, the quantitative correlation between the vertical and horizontal displacement and between the stress changes under the first and second metatarsal heads was clarified. Then, the correlation between the pressure changes of the first and second metatarsal heads in the gait cycle and the occurrence of postoperative transfer metatarsalgia was analyzed, and accurate quantitative indicators of displacement during the operation were identified.Results The forefoot loading pattern of the gait cycle assessed in the finite element model before and after percutaneous minimal invasion surgery of hallux valgus showed that when the horizontal displacement is 4 mm, the correlation between the pressure x at the distal end of the osteotomy (under the first metatarsal) and the corresponding pressure y under the second metatarsal is negative, the R value is -0.894, and the quantitative correlation is y=-0.6504x + 0.5232 with increasing vertical displacement. When the vertical displacement is 4 mm, the stress under the first metatarsal increases with the increase in horizontal displacement. Conversely, the pressure under the second metatarsal decreases. Both have a high correlation with horizontal displacement, with R values of 0.981 and − 0.890. Also, in this interval, the pressure x at the distal end of the osteotomy (under the first metatarsal) has the highest correlation with the corresponding pressure y under the second metatarsal head, the R value is -0.830, and the quantitative correlation equation is y=-0.4528x + 0.4159.Conclusion When the distal end of the first metatarsal osteotomy is shifted outwards by 4 mm, and the metatarsal side is shifted by 4 mm through bone setting manipulation during operation, percutaneous minimal invasion surgery of hallux valgus can reduce or cure hallux valgus. This might elevate the metatarsal pain during forefoot loading and avoid transfer metatarsalgia after hallux valgus operation.

Background Minimally invasive treatment of hallux valgus is one of the better surgical methods,which still has the shortcomings of insufficient correction of deformities and poor correction of hallux rotation. Therefore, we have improved the surgical method to further improve the clinical efficacy. Methods 186 patients(328 feet) who were diagnosed as hallux valgus from January 2019 to January 2020 and underwent DMMO were included in this retrospective study. The preoperative and postoperative hallux valgus angle (HVA), intermetatarsal angle (IMA) and distal articular set angle (DASA) of the patients were collected and compared to evaluate the correction of deformity. To explore the safety and effectiveness of DMMO in improving the function of hallux valgus based on American Orthopaedic Foot & Ankle Society (AOFAS) and visual analogue score (VAS). Results The preoperative HVA, IMA and DASA of the subjects were (33.63°±8.74°,12.95°±2.42°,9.46°±1.88°), postoperative HVA, IMA and DASA were (11.18°±2.04°,7.61°±1.46°,3.25°±1.15°); The preoperative AOFAS and VAS were (49.65 ± 9.32,5.61 ± 2.12), and the postoperative were (90.21 ± 7.65,1.65 ± 0.48).The postoperative(12 months) of HVA, IMA, DASA, AOFAS and VAS were better than those before operation (P < 0.05). No postoperative complications were found in all cases. Conclusion Distal metatarsophalangeal mini-invasive osteotomy in the treatment of hallux valgus is safety, scientific and effective. It is worthy of clinical application promotion. Level of Evidence:Level III

Background Traditional observational studies have found an increased risk of internal knee derangement (IKD) associated with higher body mass index (BMI). Here, we hypothesized that BMI and the risk of IKD have a causal relationship, and that high BMI is more likely to suffer from IKD. Method By reading the results of previous studies, we can assume that high BMI can increase the risk of IKD. The instrumental variables of BMI were obtained from the GIANT GWAS meta-analysis, which included approximately 700,000 individuals of European descent (n = 681,275). The IKD genetic data from IEU database, comprising 16,380,251 SNPs of European population. We performed MR analysis mainly by inverse-variance weighted (IVW), MR-Egger, Weighted median. In order to test the robustness of the correlation, we further conducted sensitivity analysis through Cochran’s Q test, MR-Egger intercept test and leave-one-out analysis. Results Genetic predisposition to higher BMI by 1 SD (SD = 4.8kg/m2) was associated with 49% higher risk of IKD (OR = 1.491; [95%CI: 1.373–1.619]; p = 1.932e-21༜0.05). Sensitivity analysis was consistent with causal interpretation, which shows that there is unlikely to be a major bias in genetic pleiotropy. Conclusions Our findings indicated that high BMI predicted by genes exerts a causal effect on increasing the risk of IKD. Further research is required to unravel the mechanism of BMI in IKD prevention.