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.
Retrospective comparative study.
Level 1 regional trauma center.
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).
Cephalomedullary nail insertion.
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.
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).
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.
Level of Evidence:
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.