Forefoot Adduction, Hindfoot Varus or Pes Cavus: Risk Factors for Fifth Metatarsal Fractures and Jones Fractures? A Systematic Review and Meta-Analysis.

The origin of fractures of the fifth metatarsus and Jones fracture is not clear. The goal of this study was to investigate the evidence of anatomical deformities such as metatarsus adductus, hindfoot varus, or pes cavus as risk factors for this pathology. A literature search of records related to the review question was performed screening PubMed/Medline, Embase and Cochrane library databases (last update: May 2020) according to PRISMA guidelines. A meta-analysis was performed using the mean difference of the assessed angles (in patients with the fractures vs controls) as outcome measure to summarize literature findings about metatarsus adductus angle (MAA) indicating forefoot adduction, calcaneal pitch angle (CP) indicating hindfoot cavus and varus deformity and Talo-1 metatarsus angle/Meary's angle (T1MA) for varus alignment. Eight studies were included in the qualitative analysis (296 patients), 5 in the quantitative synthesis (132 patients). The pooled mean difference of MAA between fracture versus control group on a per patient-based analysis was 4.62 (95% CI 1.31-7.92). Statistical heterogeneity among studies was detected (I-Square: 76.1%), likely due to different patient groups and low number of studies. The pooled mean differences of CP and T1MA among fracture group versus controls did not show statistical significance. Despite limited literature data, metatarsus adductus deformity seems to be correlated with higher risk of proximal metatarsal fractures and Jones fracture. A significant relationship between hindfoot varus or pes cavus and these fractures was not demonstrated. Further studies and trials are warranted to shed more lights on this topic.