Straight Proximal Femoral Nails Mismatch with the Anterior Bowing of the Femur

Abstract

Objective: Increased anterior how of the femur due to advanced age and osteoporosis impinges with the distal part of the non-anatomic, standard proximal femoral nails (PFN), which is one of the most preferred implant for the fixation of trochanteric fractures (TF) in the elderly. The relation between increased femoral bowing and standard PFN application was investigated.

Methods: Radiographs of 111 patients (59 men, 52 women; mean age 74.5 years), who were treated with PFN due to TF between 2011 and 2015, were evaluated retrospectively. Relation between the nail and the anterior cortex was determined by measuring the angle between distal anatomical axes of the nail and the femur (ADA). The patients were divided into two groups according to their ADA (group 1 ADA <= 4 degrees and group 2 ADA >4 degrees). Functional results and pain was evaluated using Harris Hip Score (HHS) and visual analog scale (VAS). Complications were also recorded.

Results: The mean amount of ADA was 4.5 degrees +/- 1.5 degrees. Forty-seven patients were classified in group 1 and 64 patients were in group 2. The mean HHSs were 80.6 and 79.3 (p=0,464), and the mean VAS scores were 2.13 and 5.35 (p<0.001) in group 1 and 2, respectively. Five patients were revised due to cut-out of the lag screws (total hip arthroplasty in two patients and revision of the nails in three patients). Union was achieved in all patients without infection.

Conclusion: Because straight femoral nails impinges anterior cortex of the femur with increased bowing, new design PFN with anterior curve is needed especially for shorter or osteoporotic people, or Caucasian population.