Cephalomedullary nail fixation of intertrochanteric femur fractures: Are two proximal screws better than one?

Objectives: To analyze radiographic changes in intertrochanteric (IT) fracture alignment after treatment with either a single sliding lag screw or an integrated compressed and locked, dual screw, cephalomedullary nail construct. Design: Retrospective comparative study. Setting: Level 1 regional trauma center. Patients: 1004 OTA/AO 31A, 31B2.1 fractures treated with either a single screw cephalomedullary nail (Gamma 3) or an integrated dual screw cephalomedullary nail (InterTAN) between February 1, 2005, and June 30, 2013. Four hundred thirteen remained after exclusion criteria; 130 were treated with a single screw device (79 stable and 51 unstable), and 283 with an integrated dual screw device (155 stable and 128 unstable). Intervention: Cephalomedullary nail insertion. Outcome Measures: Radiographic analysis included fracture pattern, fracture reduction, neck-shaft angle (NSA), and femoral neck shortening (FNS) differences at 3, 6, and 12 months. Measurements were normalized using known lag screw dimensions, digitally corrected for magnification. Rotation between x-rays was controlled using a ratio of known to measured dimensions. The Mann-Whitney U test was used for statistical analysis. Results: The single screw device resulted in 2.5 times more varus collapse (NSA) and 2 times more FNS over 1 year, as compared to the locked, integrated dual screw device, regardless of stability (P , 0.001). NSA and FNS changes were greater for both devices in unstable fracture patterns, but significantly less movement occurred with the dual screw device (P < 0.001). Conclusions: A cephalomedullary nail with 2 integrated proximal screws that can be compressed and then locked seems to maintain initial IT fracture reduction and subsequent position over time, with less varus collapse and less shortening than a single screw device.