Proximal Femoral Shortening and Varus Collapse After Fixation of "Stable" Pertrochanteric Femur Fractures

Objectives: To evaluate and compare femoral neck shortening and varus collapse in stable pertrochanteric femur fractures treated with sliding hip screws (SHSs) or cephalomedullary nails (CMNs). Design: Retrospective review. Setting: Academic medical center. Patients: A total of 290 patients were included in the study. The average age was 82 years, and most were women. All sustained low-energy pertrochanteric femur fractures (OTA/AO A1.1, 1.2, 1.3, 2.2) treated operatively with SHSs or CMNs. Minimum radiographic follow-up was 3 months, with an average of 28 (range 3-162) months. Intervention: CMN or SHS fixation. Main Outcome Measures: Varus collapse of the femoral neck-shaft angle and proximal femoral shortening. Results: Both implants allowed some varus collapse. Univariate analysis demonstrated a significantly greater portion of patients with SHSs progressed to varus collapse >5 degrees (P = 0.02), mild horizontal shortening >5 mm (P < 0.01), and severe horizontal shortening >10 mm (P < 0.01). There was no statistical difference in vertical shortening (P = 0.3). There was no difference in implant failure (P = 0.5), with failure rates of 3% for cephalomedullary implants and 5% for SHS constructs. Conclusions: The SHS group experienced greater varus collapse and horizontal shortening. There was no difference in overall implant failure. These findings suggest that the CMN is a superior construct for maintenance of reduction in stable pertrochanteric fractures, which may lead to improved functional outcomes as patients recover.