Short versus long proximal femoral nail anti-rotation-II (PFNA-II) in the management of unstable intertrochanteric fractures

Abstract

Objectives: Unstable intertrochanteric (IT) fractures, particularly in elderly patients with low bone mineral density, pose significant treatment challenges. Proximal femoral nail anti-rotation-II (PFNA-II) is widely used, but the optimal implant length (short vs. long) remains debated. The objective of this study was to compare the clinical and functional outcomes of short versus long PFNA-II implants in unstable IT fractures.

Methods: A prospective comparative study was conducted at a tertiary hospital from November 2018 to November 2020. Adult patients (age ≥18) with recent (≤3 weeks) unstable IT femur fractures were included. Unstable fractures were defined by comminution of the posteromedial cortex, a compromised lateral wall (including reverse obliquity), or subtrochanteric extension. Patients with pathological fractures (other than osteoporosis), open fractures, polytrauma, pre-existing ipsilateral hip pathology, or non-ambulatory status were excluded. Patients were allocated to short PFNA-II (n=38) or long PFNA-II (n=40) groups based on the surgeon's intraoperative judgment (no randomization). All patients underwent standard reduction on a fracture table and fixation with PFNA-II. Postoperative mobilization and weight-bearing protocols were adjusted according to fracture stability and fixation quality. Outcome measures included fracture union time, complications, and the Harris Hip Score (HHS). Statistical significance was set at P<0.05.

Results: Both groups had similar demographics, fracture types, and surgical durations (P>0.05). Fracture union was achieved in 94.7% (36/38) of short-nail patients and 90% (36/40) of long-nail patients, with no significant difference in union rates or time to union (mean ~14 weeks, P>0.05). The short PFNA-II group demonstrated a significantly higher final HHS (87.2±7.1 vs. 82.3±7.8, P=0.03), with 89.5% achieving good/excellent outcomes vs. 62.5% in the long-nail group. Postoperative complications differed in pattern: anterior thigh pain was more frequent in short nails (15.8% vs. 2.5%), whereas mechanical complications (varus collapse >5°, helical blade lateral migration) were more common in long nails (15% vs. 5.3% varus collapse; 10% vs. 2.6% blade migration). However, overall complication rates were not significantly different between groups (P=0.17). No deep infections, implant breakage, or cut-out occurred in either group.

Conclusion: PFNA-II fixation is effective for unstable IT fractures with high union rates and low major complication rates in both implant groups. Short PFNA-II nails yielded superior functional outcomes and fewer mechanical complications compared to long nails in similar unstable fracture patterns. These findings suggest that implant length plays a crucial role in optimizing patient outcomes. In most cases of unstable IT fractures, a short PFNA-II appears advantageous, though patient anatomy (e.g. extreme femoral curvature) and fracture morphology should be considered when selecting implant length.

Keywords: Harris Hip Score; Intertrochanteric fracture (IT); NSA (neck shaft angle); implant length; proximal femoral nail anti-rotation-II (PFNA-II).

Figure 1

Clinico-radiological outcomes of unstable intertrochanteric fracture treated with short PFNA-II. A: Pre-operative radiograph (AP and lateral) showing comminuted left intertrochanteric fracture (31A2) (unstable). B: Post-operative radiograph showing neutral-medial cortical support without anterior cortical support with center-inferior blade position. C: Follow-up radiograph at 6 months showing union. D: Final follow-up radiograph at 12 months. E: Clinical outcomes of patient at final 12 months follow-up: standing, squatting and standing on affected limb.

Figure 2

Clinico-radiological outcomes of unstable intertrochanteric fracture treated with long PFNA-II. A: Pre-operative radiographs (AP and pelvis) showing right intertrochanteric fracture with subtrochanteric extension (AO 31A3) (unstable). B: Post-operative radiograph showing negative-medial cortical support, with anterior cortical support and Centre-Centre blade position (fixed in varus). C: At 3 months follow-up X-ray showing union with maintained alignment. D: Final follow up radiograph at 12 months. E: Clinical outcome of the patient at final follow-up showing straight leg raise, squatting and standing on the affected leg.

Figure 3

Intraoperative complication seen with PFNA-II. A: Intra-operative complication of fracture shaft femur (undisplaced) seen with short PFNA-II. B: Radiograph at 6 months follow-up, showing both intertrochanteric and shaft femur fracture united.

Figure 4

An 80-year-old female with left, comminuted intertrochanteric (31A2) fracture (unstable) (A) treated with short PFNA-II at 12 months follow-up (B) showing united fracture with nail end impingement at anterior cortex causing anterior thigh pain (marked with red arrow).

Figure 5

A and B: A 65-year-old male with left, comminuted intertrochanteric fracture (31A2) (unstable) fixed with neutral reduction and centre-centre blade position with neck-shaft angle 125 degrees. C: Radiograph at 8 months follow up showing united fracture with secondary varus collapse (neck shaft angle of 116 degrees).

Figure 6

A 52-year-old male patient with comminuted, intertrochanteric (31A2.3) fracture left femur (AP and lateral views) (A and B). Post-operative radiograph (C) showing a positive reduction in AP view, without anterior cortex support in lateral view with blade position in anterior inferior zone. At follow-up of 10 months, radiograph showing implant failure due varus collapse non-union (D). Also, anterior cortex impingement can be noted which caused anterior thigh pain. He was planned for implant removal and re-fixation.

Figure 7

67-year-old female with unstable intertrochanteric (31A3) fracture at 4 months follow-up showing back out of helical blade. The implant was removed, and the fracture was fixed with DCS.