Surgical and Functional Outcomes of the Results of Conventional Two-Screw Proximal Femoral Nail (PFN) Versus Helical-Blade Anti-rotation Proximal Femoral Nail (PFNA2)

Abstract

Introduction An intertrochanteric (IT) femur fracture is an extra-capsular fracture between greater and lesser trochanters. Unstable IT fractures are those where there is poor contact between fracture fragments (especially medial and posterior cortices), comminution, and fracture pattern, such that the weight-bearing forces tend to displace the fracture further or a reverse oblique type. Proximal femoral nailing (PFN) is one of the modalities for proximal femoral fractures. A newer modality for proximal femoral fracture is PFNA2, i.e., PFN anti-rotation, which makes use of a helical blade for a better compaction of bone. Both nail designs (PFN and PFNA2) are available in short and long sizes (so a total of four variants). Only a few studies have compared the treatment of IT femur fracture concerning fracture geometry, design, and length using either of the two nail types. In our study, we assessed the surgical and functional outcomes of PFN and PFNA2. Materials and methods This prospective observational study was carried out on 30 patients who had sustained IT fractures of the femur. All cases of IT femur fractures more than 18 years of age, closed injuries, and the patients who consented to participate in this program were included in the study. All open injuries, the patients who refused to participate in this program, patients who have associated injuries, patients with a subtrochanteric femur fracture, and patients with less than six months of follow-up were excluded. The patients were randomized into two types of implant groups. All patients were operated with a standard protocol. The study was conducted for 18 months from February 2021 to August 2022. The results were analyzed (of all four variants) by comparing patient demographics, implant size, implant type, locking methods, union time, and other parameters. Results Most of the patients were operated on with a 10 mm nail diameter (17/30 patients), 380 mm length (long-nail group) (five/11 patients), and 250 mm length (short-nail group). With the use of PFNA2, the overall duration of hospital stay was less. The overall operative time (incision to wound closure) with the use of the short PFNA2 was lesser than that with the use of other designs due to the use of the zig for distal screws. The use of a distal dynamic locking screw in a majority of the patients can get better compression at the fracture site once the patient starts weight bearing and decrease the chances of the Z-effect, reverse Z-effect, screw back-out, and screw cut-out. The union time was nearly the same in the majority of the patients, with an early union seen with the use of PFNA2 nails. The overall modified Harris hip score (HHS) at the final follow-up was nearly the same with slightly better results with the use of PFNA2. Conclusions PFNA2 is the implant of choice in elderly patients with osteoporotic bone. It has less operative time, which is required in such patients with medical comorbidities; hence, it has marginal superiority over PFN. Short-nail design results in less operative time and less blood loss.

Keywords: intertrochanteric fracture; pfn; pfna2; proximal femoral nail; trochanter fracture.

Figure 1. Steinmann pin traction in the distal femur

Figure 2. Reduction checked under the C-arm

Figure 3. Steps of surgery (image intensifier television (IITV) screen images)

A: entry point, B: guide wire in the anteroposterior view, C: guide wire in the lateral view, D: nail and blade fixation, E: distal dynamic locking

Figure 4. Complications

A: reverse Z-effect, B: blade back-out

Figure 5. Images of patients showing excellent results

A: trauma radiograph, B: union radiograph, C: abduction, D: adduction, E: flexion, F: no limb length discrepancy (pelvis squared)