Outcome of the Dynamic Helical Hip Screw System for Intertrochanteric Hip Fractures in the Elderly Patients

Introduction: The dynamic helical hip system (DHHS; Synthes, Paoli, Pennsylvania) differs from the standard dynamic sliding hip screw (SHS) in that in preparing for its insertion, reaming of the femoral head is not performed, thereby preserving bone stock. It also requires less torque for insertion of the helical screw. The associated plate has locking options to allow locking screw fixation in the femoral shaft, thereby decreasing the chance of the plate pulling off. While biomechanical studies have shown improved resistance to cutout and increased rotational stability of the femoral head fragment when compared with traditional hip lag screws, there is limited information on clinical outcome of the implant available in the literature. Methods: We report a single surgeon series of 87 patients who were treated for their per-trochanteric hip fractures with this implant to evaluate their clinical outcome and compare it with a cohort of 344 patients who were treated with the standard SHS. All data were prospectively collected, most as part of a structured Geriatric Fracture Care Program. Results: The 2 groups were similar demographically, and medically, with similar rates of in-hospital complications and implant failure. Failure in the DHHS group was attributable to use of the implant outside its indications and repeated fall of the patient. Conclusion: This limited case series showed that the DHHS outcomes are comparable with that of the SHS. Whether there is any benefit to its use will require larger, prospective randomized controlled trials