Nonunion, Reoperation Predictors in Tibia Fracture Patients
Nonunion, Reoperation Predictors in Tibia Fracture Patients
We identified 594 potentially eligible patients from the hospital database review. Of these, 200 were included in our analysis. Patients were excluded if they had an insufficient amount of follow-up clinical or radiographical data (141), a tibial fracture not fixed via operative internal fixation (108), a fracture extending into the joint (87), a non-tibial fracture (35), a bilateral fracture (17), or were under the age of 18 (6). The typical patient was a healthy male (69.0%), averaging 42 years of age, who consumed alcohol (73%), and had no previous injuries to the ipsilateral tibia (98%) (Table 1). Most tibial fracture injuries were accompanied by injuries to the ipsilateral fibula (92%). Of the fractures included, 43% were a result of a motor vehicle-related incident. Fracture injuries tended to be closed (78%) and were treated with reamed intramedullary nailing (81%). Post-operatively, patients did not suffer from any fracture complications during their hospital stay (97%), which was often less than a week (Table 2).
In our cohort of tibial fractures, 37 (18.5%) went on to nonunion, as identified by the attending physician. Of the 37 patients with nonunion, 62.2% of them were identified within the first six months of the initial injury. Additionally, 27 (13.5%) of all included patients underwent a reoperation, with 55.6% of them occurring within the first six months of the initial injury.
Univariable analysis identified six fracture characteristics associated with the incidence of nonunion (p < 0.05), which included fractures with less than 25% cortical continuity (odds ratio = 6.44 [95% CI 1.89, 21.95]; p = 0.003), open fractures (odds ratio = 2.56 [95% CI 1.24, 5.29]; p = 0.011), the presence of comminution (odds ratio = 2.21 [95% CI 1.05, 4.66]; p = 0.037), and an oblique (odds ratio = 2.94 [95% CI 1.32, 6.58]; p = 0.009) or segmental (odds ratio = 3.17 [95% CI 0.96, 10.46]; p = 0.058) fracture type (Table 3). Multivariable logistic regression analysis suggested that only cortical continuity remained predictive (odds ratio = 4.72 [95% CI 1.33, 16.76]; p = 0.02) (Table 4).
Alternatively, open fractures and transverse fractures were the only fracture characteristics that showed any significant predictive value for reoperation, as shown via univariable analysis (Table 5). All tibial fractures with less than 25% cortical continuity accounted for all 27 reoperations we identified in our sample. The presence of a transverse fracture was the only variable to approach significance for the incidence of reoperation in the multivariable logistic regression analysis (odds ratio = 3.03 [95% CI 1.00, 9.18]; p = 0.05) (Table 6).
Of the 37 nonunions reported in this study, 32.4% of them were treated with a noninvasive therapy option alone to promote bony union. Such options include, but are not limited to, ultrasound therapy, electrical stimulation, or medication. Additionally, 40.5% of the nonunions were treated with a reoperation alone and 24.3% were treated with a combination of both noninvasive therapies and a reoperation. There was only one case who did not receive any secondary treatment for nonunion.
A previous index identified open fractures, presence of a fracture gap post-fixation, and a transverse fracture type as variables in a predictive model for reoperation within one year following operative management of tibial fractures.
Using the same prognostic risk model (Table 7), our findings largely confirmed the incremental increase in the risk of reoperation with one, two, and three prognostic risk factors. Patients with at least two of the three risk factors were more likely to develop a nonunion, with the presence of both a fracture gap and open fracture having the highest predictive value for a nonunion over any other aggregate of two of the three variables included in the prognostic risk model (Table 8). Patients with at least two or all three risk factors were more likely to incur a reoperation. All possible aggregates of two of the three prognostic risk variables provided a predictive basis for reoperation (Table 9).
Chi-square analysis found an association between nonunion and reoperation, χ (1, N = 198) = 101.4, p < 0.001. 12.1% of all included patients experienced both a nonunion and a reoperation and patients with a nonunion were 97 times (95% CI 25.8–366.5) more likely to have a reoperation.
Results
Characteristics of the Patients
We identified 594 potentially eligible patients from the hospital database review. Of these, 200 were included in our analysis. Patients were excluded if they had an insufficient amount of follow-up clinical or radiographical data (141), a tibial fracture not fixed via operative internal fixation (108), a fracture extending into the joint (87), a non-tibial fracture (35), a bilateral fracture (17), or were under the age of 18 (6). The typical patient was a healthy male (69.0%), averaging 42 years of age, who consumed alcohol (73%), and had no previous injuries to the ipsilateral tibia (98%) (Table 1). Most tibial fracture injuries were accompanied by injuries to the ipsilateral fibula (92%). Of the fractures included, 43% were a result of a motor vehicle-related incident. Fracture injuries tended to be closed (78%) and were treated with reamed intramedullary nailing (81%). Post-operatively, patients did not suffer from any fracture complications during their hospital stay (97%), which was often less than a week (Table 2).
Nonunions and Reoperations
In our cohort of tibial fractures, 37 (18.5%) went on to nonunion, as identified by the attending physician. Of the 37 patients with nonunion, 62.2% of them were identified within the first six months of the initial injury. Additionally, 27 (13.5%) of all included patients underwent a reoperation, with 55.6% of them occurring within the first six months of the initial injury.
Factors Associated With Nonunion and Reoperation
Univariable analysis identified six fracture characteristics associated with the incidence of nonunion (p < 0.05), which included fractures with less than 25% cortical continuity (odds ratio = 6.44 [95% CI 1.89, 21.95]; p = 0.003), open fractures (odds ratio = 2.56 [95% CI 1.24, 5.29]; p = 0.011), the presence of comminution (odds ratio = 2.21 [95% CI 1.05, 4.66]; p = 0.037), and an oblique (odds ratio = 2.94 [95% CI 1.32, 6.58]; p = 0.009) or segmental (odds ratio = 3.17 [95% CI 0.96, 10.46]; p = 0.058) fracture type (Table 3). Multivariable logistic regression analysis suggested that only cortical continuity remained predictive (odds ratio = 4.72 [95% CI 1.33, 16.76]; p = 0.02) (Table 4).
Alternatively, open fractures and transverse fractures were the only fracture characteristics that showed any significant predictive value for reoperation, as shown via univariable analysis (Table 5). All tibial fractures with less than 25% cortical continuity accounted for all 27 reoperations we identified in our sample. The presence of a transverse fracture was the only variable to approach significance for the incidence of reoperation in the multivariable logistic regression analysis (odds ratio = 3.03 [95% CI 1.00, 9.18]; p = 0.05) (Table 6).
Secondary Treatment Profile for Nonunions
Of the 37 nonunions reported in this study, 32.4% of them were treated with a noninvasive therapy option alone to promote bony union. Such options include, but are not limited to, ultrasound therapy, electrical stimulation, or medication. Additionally, 40.5% of the nonunions were treated with a reoperation alone and 24.3% were treated with a combination of both noninvasive therapies and a reoperation. There was only one case who did not receive any secondary treatment for nonunion.
Validation of Previous Prognostic Index for Reoperation
A previous index identified open fractures, presence of a fracture gap post-fixation, and a transverse fracture type as variables in a predictive model for reoperation within one year following operative management of tibial fractures.
Using the same prognostic risk model (Table 7), our findings largely confirmed the incremental increase in the risk of reoperation with one, two, and three prognostic risk factors. Patients with at least two of the three risk factors were more likely to develop a nonunion, with the presence of both a fracture gap and open fracture having the highest predictive value for a nonunion over any other aggregate of two of the three variables included in the prognostic risk model (Table 8). Patients with at least two or all three risk factors were more likely to incur a reoperation. All possible aggregates of two of the three prognostic risk variables provided a predictive basis for reoperation (Table 9).
Association Between Nonunions and Reoperations
Chi-square analysis found an association between nonunion and reoperation, χ (1, N = 198) = 101.4, p < 0.001. 12.1% of all included patients experienced both a nonunion and a reoperation and patients with a nonunion were 97 times (95% CI 25.8–366.5) more likely to have a reoperation.