Fixation of femoral neck fractures using divergent versus parallel cannulated screws

Controversy exists regarding the optimal method of internal fixation in femoral neck fractures. Biomechanical data suggest that calcar fixation is superior to central screws placement. We propose a divergent technique for placing 3 cannulated stainless steel screws engaging the calcar femorale. Fifty two patients admitted to our institution for a femoral neck fracture were treated with the divergent screw technique, over a 7-year period. Four patients were deceased and 4 were lost to follow-up. Of the remaining 44 patients there were 10 males and 34 females, aged from 33 to 78 years (mean, 58 years). All patients were operated on by the same surgeon and were followed-up for a minimum of 2 years (mean: 33.6 months, range: 2-6 years). Twenty four patients sustained a non-displaced fracture (Garden I-II) and 20 sustained a displaced fracture (Garden III-IV) of the femoral neck. Mean Harris hip score (HHS) was 89.6 points. Avascular necrosis was evident in 4 patients (9%) with displaced fractures. Non-unions or failed internal fixations were not encountered. There was a significant difference in the HHS, in favor of the divergent group (P = 0.006), while more complications were encountered in the parallel group including 6 cases with non-union. In conclusion, parallel screw placement is not critical for an excellent clinical outcome. Our proposed fixation method using 3 screws that diverge and lie in different coronal planes (1 engaging the calcar femorale) with a free-hand technique may offer enhanced fixation. Biomechanical data along with larger clinical studies are needed to establish our proposed method.