Addition of an Anti-rotation Screw to the Dynamic Hip Screw for Femoral Neck Fractures

The authors investigated the use of an anti-rotation screw with the dynamic hip screw (DHS) during internal fixation of Garden I and II femoral neck fractures. Sixty-five patients with Garden I and II femoral neck fractures (mean age, 70 years) were treated with internal fixation at the authors' institution. In 31 patients, a 2-hole DHS was used alone (group 1), and in 34 patients, the DHS was combined with an anti-rotation screw placed in the cranial part of femoral head and neck (group 2). Patients' preinjury function and mental level were assessed using the Barthel index and the Abbreviated Mental test, respectively. The outcome measures included cost implications, operative time, and intraoperative radiation dose. The modified Harris Hip Score and a radiological assessment were performed at a mean of 11 months (range, 8-24 months) postoperatively. The use of the anti-rotation screw was associated with a longer operative time (mean, 44.54 minutes in group 1 vs 51.52 minutes in group 2; P<.0001) and more fluoroscopy screening (mean dose area product, 28.39 cGy/cm(2) in group 1 vs 44.33 cGy/cm(2) in group 2; P=.03). The additional cost of using an anti-rotation screw was 106 pound ($170) per case. No difference existed between the 2 groups with regard to radiological union, onset of avascular necrosis, and rate of revision surgeries. An anti-rotation screw, used with the dynamic hip screw, involves extra costs, prolongs operative time, and requires more intraoperative fluoroscopy screening but offers no advantages with regard to fracture union.