Objective: To investigate the risk factors for delayed union of extra-articular fractures of the middle and lower third of the tibia treated by locking plate.
Methods: Total of 135 patients of extra-articular fractures of the middle and lower third of the tibia from January 2013 to December 2018 were retrospectively analyzed, including 85 males and 50 females, ranged from 19 to 80 years old. All cases were treated with locking plates. The patients were divided into union group and delayed union group according to the condition of fracture union. The risk factors of delayed healing were determined by univariate analysis of 14 factors that might affect fracture healing first, then the factors with significance were analyzed by binary Logistic regression.
Results: There were 13 patients of delayed union, and the rate of delayed union was 9.63%. Univariate analysis showed that delayed union was associated with age, smoking, reduction method, anemia and time of preoperative preparation. Regression analysis showed that age[OR=0.849, 95%CI（0.755, 0.954）, P=0.006], smoking[OR=0.020, 95%CI（0.002, 0.193）, P=0.001], reduction method[OR=23.924, 95%CI（2.210, 258.943）, P=0.009], anemia[OR=0.016, 95%CI（0.001, 0.289）, P=0.005] were the contributory factors for delayed union.
Conclusion: Young age, smoking, closed reduction and anemia are the risk factors for delayed union of extra-articular fractures of the middle and lower third of the tibia treated by locking plate.
Keywords: Fracture healing; Fractures; Internal fixation; Risk factors; Tibial fractures.