Prevalence and Associated Factors of Nonunion in Open Tibial Shaft Fracture among Patients Treated with External Fixation in Tibebe Ghion Specialized Hospital

Background: The definitive treatment of open tibial shaft fractures remains challenging and nonunion after treatment of open tibial shaft fractures with external fixation complicates a significant proportion of cases. There are varying rates of occurrence of nonunion and the prevalence is not well known in Ethiopia. The objective of the study is to assess the prevalence and associated factors of nonunion in open tibial shaft fractures treated with EX FIX in TGSH. Methods: The study was conducted using a cross-sectional study in patients with open tibial shaft fractures who were admitted and treated with external fixation in the Tibebe Ghion Specialized Hospital orthopedics department from January 1, 2019, to January 29, 2021. The study involved 75 patients, which was the total number of cases in the study period and fulfilled the inclusion criteria. Bivariate and multiple variable logistic regression analyses were used to analyze the association between variables. The degree of association between variables was determined at the p-value of <0.05. Results: The overall prevalence of nonunion in open tibial shaft fractures treated with external fixation in TGSH was 21.3%. The severity of the injury, presence of wound infection, and treatment factors affect the occurrence of nonunion. It occurs in 9 of 19 (47.4%) Gustilo-Anderson grade IIIB fractures and 6 of 48 (12.5%) Gustilo-Anderson grade IIIA fractures. A delay in soft tissue covering of Gustilo-Anderson grade IIIB fracture of 15 days or more increases the nonunion rate to 72.7%. Nonunion occurred in 41.7% of cases with SSI and 11.8% of cases without SSI. Gustilo-Anderson grade (AOR=4.85, CI 95%: 1.31-18.01), surgical site infection (AOR=4.12, CI 95%: 1.11-15.26), and time until coverage of bone of Gustilo-Anderson grade IIIB fracture (AOR=18.23, CI 95%: 1.17-284.8) have statistically significant association with nonunion. Conclusion and Recommendation: External fixation use for definitive treatment of open tibial fractures should be disfavored as the prevalence of nonunion in open tibial shaft fractures treated with EX FIX is higher than other previous studies done in European and Asian countries. Gustilo-Anderson grade of injury, surgical site infection, and time from injury to bone coverage of Gustilo-Anderson grade IIIB fractures were found to be statistically significantly associated with the occurrence of nonunion. Therefore, attention should be given to early soft tissue reconstruction of exposed bones to establish a favorable environment for bone healing and to make treatment with internal fixations possible. Better management of wounds to minimize surgical site infections is required for better healing of open tibial shaft fractures. Prospective studies are also recommended on the issue.