Primary arthrodesis as a treatment of choice for “unsalvageable” pilon fractures

Background. The treatment of comminuted AO/OTA type 43C3 pilon fractures remains a clinical challenge. Attempts at open reduction and internal fixation (ORIF) in cases with significant articular surface destruction and severe soft tissue damage (“unsalvageable” fractures) are associated with high complication rates and poor outcomes, combined with a significant duration, multi-stage treatment and significant socio-economic costs. The search for optimal treatment strategies in the most severe injuries remains relevant. Objective: to compare clinical and functional outcomes of primary ankle arthrodesis (main, prospective group) with staged ORIF results (comparison, retrospective group) in patients with severe type 43C3 pilon fractures, and to validate criteria for identifying “unsalvageable” cases. Materials and methods. A prospective-retrospective comparative study was conducted. Group 1 (comparison, retrospective) included 34 patients treated from 2018 to 2022 who underwent staged ORIF to possibly restore the anatomy of the joint and preserve its function. Group 2 (main, prospective) consisted of 30 patients treated from 2022 to 2024 who underwent primary arthrodesis based on “unsalvageable” fracture criteria. These criteria included articular surface destruction (> 3 major fragments and/or central impaction > 5 mm), bone loss (> 25 % volume), and severe soft tissue damage (Gustilo-Anderson II–IIIA). Primary endpoints were nonunion and deep infection rates. Secondary endpoints were AOFAS functional score at 12 months and time to full weight-bearing. Statistical analysis was performed using Fisher’s exact test and Mann-Whitney test (p < 0.05). Results. In the retrospective ORIF group, nonunion rate was 11.8 % and deep infection rate was 17.6 %. In the prospective arthrodesis group, fusion was achieved in 93.3 % of cases with a nonunion rate of 6.7 % (p = 0.674). Deep infection occurred in 6.7 % of patients versus 17.6 % in the comparison group (p = 0.265). Mean AOFAS score at 12 months was 79.2 ± 11.8 (95% CI: 74.8–83.6) in the arthrodesis group versus 75.5 ± 15.0 (95% CI: 70.3–80.7) in the ORIF group (p = 0.284). Time to full weight-bearing was significantly shorter in the arthrodesis group (9.8 ± 2.3 weeks versus 16.8 ± 4.1 weeks; p < 0.001). Reoperation rate was 10.0 % (95% CI: 2.1–26.5) in the arthrodesis group versus 41.2 % (95% CI: 24.7–59.3) in the ORIF group (p = 0.006). Conclusions. For patients with “unsalvageable” type 43C3 pilon fractures, primary arthrodesis demonstrated lower risk of infectious complications, significantly faster recovery of weight-bearing function, and reduced need for reoperations compared to ORIF. The developed “unsalvageability” criteria allow for effective identification of patients indicated for primary arthrodesis.