Outcomes of two circular external fixation systems in the definitive treatment of acute tibial fracture related infections

Acute tibial fracture-related infection (FRI) is one of the most feared and challenging complications after a tibial fracture. The most appropriate treatment in this scenario is far from a resolved topic. Circular external fixators (CEFs) offer multiplanar control and minimize soft tissue injury using temporary implants far from the infected area. This study aimed to investigate the outcomes of two different types of CEFs (Ilizarov and hexapod) in the treatment of a series of acute tibial FRIs. A retrospective study at two specialized limb reconstruction centres identified all patients with an acute tibial FRI (≤4 weeks after index procedure) definitively treated with a CEF from January 2015 to December 2020. Primary outcomes: fracture healing and infection eradication rate with a minimum FU of 12 months after frame removal. Secondary outcomes: to investigate the differences between the two types of circular frames regarding final post-treatment deformity magnitude. We included 31 patients with acute tibial FRIs: 18 treated with hexapod-type and 13 with Ilizarov-type CEFs. Average age was 45.5±16.56 years. Fracture healing and infection eradication were achieved in all patients (31/31) after a mean follow-up of 24.7 months (range 12.1-55.3). Patients treated with an Ilizarov-type fixator presented shorter time to fracture union (5.5±2.2 months vs. 9.2±6.0 months; p-value 0.021) and shorter duration of external fixation (p-value 0.001). Regarding residual post-treatment deformity, the hexapod system presented significantly less residual coronal translation deformity (p-value 0.034) and better callus quality. Fixator-related complications were similar when comparing the two groups. No significant differences were seen in pain (p-value 0.25), RTW rate (35% vs. 45%; p-value 0.7) or functionality (p-value 0.4). Definitive circular external fixation is an excellent treatment for acute tibial FRI. Both Ilizarov and hexapod systems offer a very high rate of fracture healing and infection eradication. Although both presented very low radiological post-operative residual deformity, the hexapod system showed less residual coronal translation deformity and better callus quality.