Locking plates increase the strength of dynamic hip screws Dylan P.A. Jewell a, * , Sabina Gheduzzi b , Mark S. Mitchell b , Anthony W. Miles b a University Hospital Birmingham NHS Trust, Raddlebarn Road, Selly Oak, Birmingham B29 6JD, UK b Centre for Orthopaedic Biomechanics, Department of Mechanical Engineering, University of Bath, BA2 7AY, UK Accepted 28 May 2007 Injury, Int. J. Care Injured (2008) 39, 209—212 www.elsevier.com/locate/injury KEYWORDS Hip fractures; Intertrochanteric; Locking plate Summary Introduction: Failure of a dynamic hip screw (DHS) fixation leads to decreased mobility of the patient and frequently to a decrease in general health. The most common mode of failure of a DHS is cut out of the lag screw from the femoral head. The second most common mode of failure is lift-off of the plate from the femur. The aim of this laboratory-based experimental study was to determine whether a DHS secured to an osteoporotic femur with a locking screw plate would provide a stronger construct than the standard DHS plate. Method: The standard DHS design was compared to a DHS with fixed angle locking screws holding the DHS plate to the femur. Standard dynamic compression plates (DCP) and locking compression plates (LCP) were attached to synthetic, osteoporotic bone. A load was applied to replicate the forces occurring following the fixation of unstable, intertrochanteric hip fractures. A bracket on the proximal end of the plate replicated the lag screw in the femoral head. The constructs were cyclically loaded by a screw-driven material-testing machine and the number of cycles before failure occurred was determined. Results: The mean number of cycles to failure for the locking plate construct was 2.6 times greater than for the standard screw construct (285 versus 108 cycles, respec- tively p = 0.016). Conclusion: A dynamic hip screw with fixed angle locking screws would reduce the risk of DHS failure. A locking screw DHS would be particularly useful in patients with osteoporotic bone, and in patients with less stable fracture configurations. # 2007 Elsevier Ltd. All rights reserved. * Corresponding author at: Treslay House, Rowney Green Lane, Rowney Green, Alvechurch B48 7QE, UK. Tel.: +44 7932749282. E-mail address: dylanjewell@yahoo.com (D.P.A. Jewell). 0020–1383/$ — see front matter # 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2007.05.018