Predictors of mechanical complications after intramedullary nailing of tibial fractures.

INTRODUCTION: Intramedullary (IM) nailing is the gold standard treatment for tibial shaft fractures, but can be associated with various mechanical complications, including delayed union.

HYPOTHESIS: We believe that complications do not occur randomly, but in certain conditions that contribute to their development. Risk factors likely to predict delayed union can be identified to support prevention.

MATERIALS AND METHODS: A cohort of 171 fractures treated by IM nailing between 2005 and 2015 was reviewed retrospectively. Independent variables included intrinsic, patient-related factors and extrinsic factors such as those related to the fracture or surgery. A multiple logistic regression model was used to determine which factors can predict each type of complication.

RESULTS: Delayed union occurred in 22.8% of patients. Smoking and high-energy trauma were risk factors. Hardware breakage was significantly reduced (p<0.05) when the nail diameter was greater than 10mm. A nail diameter/reamer diameter ratio outside the recommended limits (0.80-0.99) was more likely to be associated with screw failure. Diabetes is a risk factor for hardware migration, which itself is associated with other complications.

DISCUSSION: Nonunion is the most common complication after IM nailing of tibial shaft fractures. Smoking cessation after a fracture is necessary in our opinion, even if the literature is ambivalent on this aspect and stopping to smoke once the fracture occurs may not be sufficient to prevent a poor outcome. Use of a nail diameter/reamer diameter between 0.80 and 0.99 favors union and prevents hardware breakage. Hardware migration in a diabetic patient may be a warning sign of other types of complications.

LEVEL OF EVIDENCE: Retrospective cohort study. Level IV.