Radiographic union rate and predictors of nonunion after primary surgical implant generation network intramedullary nailing for open tibial shaft fractures at a major trauma center in Ethiopia

Objectives: Open tibial shaft fractures are a major source of morbidity in low- and middle-income countries, yet outcome data after Surgical Implant Generation Network (SIGN) intramedullary nailing (IMN) remain few. The study aimed to determine the radiographic union rate and identify predictors of nonunion after primary SIGN IMN for Gustilo–Anderson (GA) grade I through IIIA open tibial shaft fractures at a large trauma center in Addis Ababa, Ethiopia. Methods: A retrospective cross-sectional study was conducted at AaBET Hospital, reviewing records and radiographs of patients treated between July 2016 and July 2022. Radiographic union was assessed at minimum 1 year using the Radiographic Union Scale for Tibial Fractures (RUST). Associations between clinical variables and union were analyzed with Fisher exact test, Mann–Whitney U test, and binary logistic regression. Results: Eighty-seven patients met inclusion criteria (mean age 32.9 years; 86.2% male). Road traffic accidents accounted for 78.2% of injuries. The radiographic union rate was 89.7% (78 of 87). On multivariable analysis, GA grade IIIA (odds ratio [OR]: 36.2; 95% confidence interval [CI]: 4.21–90; P = 0.013), postoperative infection (OR: 20.2; 95% CI: 2.15–189; P = 0.023), and surgical delay beyond 48 hours (OR: 16.5; 95% CI: 1.88–144; P = 0.009) were independently associated with nonunion. Conclusions: Primary SIGN IMN yielded a high union rate for GA I to IIIA open tibial shaft fractures in this low- and middle-income countries setting. GA grade, postoperative infection, and delay to surgery were the principal barriers to union. These findings support early surgical intervention and rigorous infection control in resource-limited settings. Level of Evidence: Prognostic Level IV.