Femoral head necrosis after treatment of femoral neck fractures with compressive hollow screws

Objective To explore the influencing factors of femoral head necrosis after treatment of femoral neck fractures with compressive hollow screws.Methods From January 2000 to September 2008,we treated 172 patients with femoral neck fracture by fixation with compressive hollow screws.They were 107 men and 65 women,with an average age of 38.5 years (from 13 to 55 years).By Garden classification,there were 6 cases of type Ⅰ,40 cases of type Ⅱ,90 cases of type Ⅲ and 36 cases of type Ⅳ.The time from injury to surgery averaged 8.3 days.Incidence of femoral head necrosis was calculated according to the radiographs of the fractured hip at the follow-up.The Harris scores at 48 months after surgery were compared between the necrosis and non-necrosis groups.Multivariate logistic regression analyses were conducted to explore the influencing factors of femoral head necrosis.Results All the 172 patients obtained a mean follow-up of 54 months (from 30 to 86 months).Femoral head necrosis occurred in 14 cases (8.1％ ).The total average Harris score for this series was 85.9 points (from 57 to 99 points).Screw removal,fracture type,bone density,gender and postoperative weight-bearing time were found to be significantly associated with the incidence of femoral head necrosis.The screw removal was the most closely associated with the necrosis ( P =0.002).Conclusion After treatment of femoral neck fractures with compressive hollow screws,it should be prudent to remove the compressive hollow screws,because they may have a negative impact on the blood supply in the femoral head and induce femoral head necrosis. Key words: Femoral head fracture;  Fracture fixation, internal;  Bone nail;  Femoral head necrosis