A Comparison of Two Proximal Femoral Nail Devices For Fixation of Unstable Intertrochanteric Femur Fractures

Background: Unstable intertrochanteric femur fractures are common fractures posing a surgical challenge in reduction and fixation. The fixation devices frequently used are based on hip intramedullary nailing with femur head lag screw or blade. The aim of this paper is to compare between two different proximal femoral nail (PFN) with double screw mechanics. Methods: We retrospectively reviewed 386 unstable pertrochanteric femur fractures surgically treated in our hospital from 2000 to 2009. Of these 227 patients had either a complication or completed six months recorded follow-up with fracture resolution. One hundred and forty seven fractures (64.8%) were fixed by the Targon proximal femur (TPF) device (Aesculap, Tuttlingen, Germany) and 80 fractures (35.2%) were fixed using the antirotation trochanteric nailing system (ATN) device (dePuy, Warsaw, IN, USA). We compared the clinical and surgical immediate outcome (e.g., tip apex distance, reduction quality), between the fixation devices. Long term results, i.e., complications, revisions and survival rates, were compared as well. Results: We found higher rates of complications in patients treated by the ATN device (32.5%) as compared to the patients treated by the TPF device (14.9%). This difference was statistically significant (p value= 0.002). In the ATN group 15 patients (18.8%) required revision surgery as compared to 18 patients (13.4%) requiring surgery in the TPF group. This difference was not statistically significant (p value =0.18). Multivariate logistic regression found that ATN fixation device increased the odds ratio for any complication by 2.82 (95% CI 1.29-6.16). One year survival for patients treated by the ATN and Targon PF devices were 84.1% (95% CI = 79.6%-88.6%) and 76.4% (95% CI = 69.1%-83.6%), respectively. This difference was statistically significant (p value = 0.047). Conclusions: Although the two devices compared share similar biomechanical properties, e.g., double screw design, their outcome differed. Better outcome was observed in the Targon PF group. Our results implicate that clinical trials results using a specific fixation device cannot be easily extended to other devices with similar designs.