A multiple correlation factor analysis of femoral head necrosis in patients over 45 years old with femoral neck fractures after closed reduction and cannulated screws fixation

Objective To investigate the multiple factors correlated to femoral head necrosis in patients over 45 years old with femoral neck fractures after closed reduction and cannulated screws fixation.Methods Three hundred patients with femoral neck fracture were admitted from May 1999 to May 2004 and treated by closed reduction and internal fixation with cannulated screws.We analyzed the multiple factors:age,gender,Garden classification,follow-up time,procedure delay,quality of reduction,time of full-weight-loading,fixation removal, and preoperative traction.Multiple correlation factors were analyzed by SPSS10.0 statistic system.Results Complete case records were documented in 99 cases who were followed up for an average of 24.5 months(range,8 to 60 months).Femoral head necrosis occurred in 15 cases(15.2%).Time of femoral head necrosis was 8 to 50 months after operation.The combination of quality of reduction,preoperative traction,age,and age×fixation re- moval was found to have the most significant influence on femoral head necrosis after internal fixation for femoral neck fractures.Conclusions Good reduction is the most important factor correlated to the outcome of a femoral neck fracture.Age is linked to the risk of necrosis but it is relatively insignificant.Preoperative traction in wrong positions can increase the incidence of necrosis.Garden classification is important in predicting femoral head necrosis and is associated with quality of reduction,but it is not a risk one in the combination of multiple correlation factors that lead to the necrosis.