Objective: To evaluate the therapeutic effects of cannulated compression screws for the treatment of femoral neck fractures, and to investigate the related factors influencing the avascular necrosis of femoral head after surgery.
Methods: A retrospective review was done for 96 patients with femoral neck fractures treated with cannulated compression screws from January 2003 to June 2009. Among them, there were 44 males and 52 females with 21 to 88 years old (averaged 56.3 years old). According to Garden classification, 4 patients were type I, 34 patients were type II, 37 patients were type III and 21 patients were type IV. Factors such as patients' age, gender, fracture type, duration from injury to surgery and fracture reduction quality were statistically analysed to find correlations with nonunion and avascular necrosis of femoral head.
Results: Eighty-four patients were followed up ranging from 9 to 60 months and the mean time was 25.4 months. Postoperative complications included deep venous thrombosis of lower extremity in 2 cases, bone nonunion in 8 cases and avascular necrosis of femoral head in 11 cases. According to Harris criterion, the total postoperative Harris score was 86.20 +/- 11.00, and 40 patients got an excellent result, 32 good, 7 fair and 5 poor. The incidence of avascular necrosis of femoral head in nondisplaced fracture group and displaced fractures group were 3.22% and 18.87% respectively;and there were significant difference between the two groups (P = 0.037). The incidence of avascular necrosis of femoral head in anatomical reduction group and non-anatomical reduction group were 5.00% and 20.45% respectively; also,significant difference was existed between the two groups (P = 0.036). However, there was no statistically significant difference of the incidence of avascular necrosis of femoral head according to different age, sex, operative time.
Conclusion: The therapeutic effect of cannulated compression screws for non-displaced femoral neck fractures is good. The fracture type and reduction quality are found to be main factors correlated with avascular necrosis of femoral head statistically. For young patients with a displaced femoral neck fracture,in order to avoid incidence of avascular necrosis of femoral head, anatomical reduction should be ensured. For elder patients with a severe displaced femoral neck fracture, the total hip replacement should be recommended.