Purpose: We wanted to analyze the influences of risk factors on avascular necrosis and nonunion after multiple pinning for a femoral neck fracture.
Materials and Methods: Among the cases of multiple pinning for a femoral neck fracture that were seen at our department from June 1995 to May 2006, we analyze 102 cases that had more than 2 years of follow-up. We evaluated the influence of such factors as the age, gender, injury on the right- or left-side, the degree of displacement, the time to operation, the angle of fracture, the accuracy of reduction and posterior cortex comminution on avascular necrosis and nonunion after multiple pinning for a femoral neck fracture.
Results: The incidences of AVN and nonunion were 13.7% (14/102) and 10.7% (11/102), respectively. The degree of displacement was a significant factor that influenced the development of nonunion (p<0.05). The time to operation and the angle of fracture were significant factors that influenced nonunion (p<0.05 & p<0.05) and avascular necrosis (p<0.05 & p<0.05). The posterior cortex comminution was a significant factor that influenced nonunion (p<0.05) and avascular necrosis (p<0.05).
Conclusion: The important risk factor for avascular necrosis was the angle of fracture over 60 degrees. The important risk factors for nonunion were the time to operation (over 24 hours), posterior cortex comminution and an angle of fracture over 60 degrees.

Keywords: Femoral neck fracture, Multiple pinning, Avascular necrosis, Nonunion, Risk factors