The aim of this retrospective study was to evaluate the failure rate among different fixation devices for undisplaced fracture neck of femur. All 52 patients with Garden I and II hip fractures who underwent surgery in a teaching hospital in London from January 2007 to June 2012 were included. Electronic patient records were accessed to collect the patient data.

There were 52% females and the mean age of patients was 70 years. Thirty patients had cannulated screws, 18 – dynamic hip screw (DHS) with de-rotation screw and 4 had DHS alone. Initial results showed that 36% patients had re-operation. 7(77%) had total hip replacement and 1(11%) had metal work removal. The reason for revision was failure of fixation in 8 (88%) and avascular necrosis in 1 (11%). There was significantly higher failure rate in the DHS with derotation screw group (50%) compared to the cannulated screw group (35%) and the DHS alone group (0%). Average time to planned revision was 11.1 months.

Traditionally undisplaced intra capsular hip fractures are treated by in-situ fixation using different devices. Biomechanically DHS with de-rotation screw achieves better rotational and axial stability compared to other fixation devices. However, our study showed a higher failure rate in this group. Inability to achieve a perfectly parallel screw position seems to be a significant factor responsible for high failure. Higher failure rates with fixation may boost the role of replacement arthroplasty as one off surgical treatment in elderly patients.