Background:: The epidemiology of midfoot injuries is poorly known. It has been estimated that the incidence of Lisfranc injuries (intra-articular injury in the tarsometatarsal joint) is 1/55 000 person-years and the incidence of Chopart injuries (intra-articular injury in the talonavicular and calcaneocuboidal joint) 4/100 000 person-years. The purpose of our study was to assess the computed tomography (CT) imaging-based incidence (per 100 000 person-years) and trauma mechanisms of midfoot injuries.
Methods:: All CT studies performed due to acute injury of the foot and ankle region between January 1, 2012, and December 31, 2016, at Tampere University Hospital were reviewed. Patients presenting with an injury in the midfoot region in the CT scan were included in this study, and their records were retrospectively evaluated to assess patient characteristics.
Results:: During the 5-year study period, 953 foot and ankle CT scans were obtained because of an acute injury of the foot and ankle. Altogether, 464 foot injuries were found. Of these, 307 affected the midfoot area: 233 (75.9%) the Lisfranc joint area, 56 (18.2%) the Chopart joint area, and 18 (5.9%) were combined injuries or miscellaneous injuries in the midfoot. The incidence of all midfoot injuries was 12.1/100 000 person-years. The incidence of Lisfranc injuries was 9.2/100 000 person-years. The incidence of Chopart injuries was 2.2/100 000 person-years.
Conclusions:: The incidence of Lisfranc injuries was higher and the incidence of Chopart injuries lower than previously estimated. More than two-thirds of the midfoot injuries in this study were nondisplaced (<2 mm displacement in fracture or joint) and were caused by low-energy trauma.
Level of evidence:: Level III, epidemiologic study.
Keywords: Chopart; Lisfranc; epidemiology; incidence; injury; joint; tarsometatarsal; trauma.