Does PFNA II avoid lateral cortex impingement for unstable peritrochanteric fractures?

BACKGROUND: Proximal femoral nail antirotation devices (PFNAs) are considered biomechanically superior to dynamic hip screws for treating unstable peritrochanteric fractures and reportedly have a lower complication rate. The PFNA II was introduced to eliminate lateral cortex impingement encountered with the PFNA. However, it is unclear whether the new design in fact avoids lateral cortex impingement without compromising stability of fixation and fracture healing. QUESTIONS/PURPOSES: We therefore asked whether the PFNA II: (1) eliminates the lateral cortex impingement and fracture displacement experienced with PFNA; and (2) provides stable fracture fixation with a low major complication rate for unstable fractures in European patients.
METHODS: We retrospectively reviewed 108 patients with an unstable peritrochanteric fracture, 58 treated with PFNA and 50 with PFNA II. We compared nail positioning, major and minor complication rates, operative and fluoroscopy time, blood transfused, time to mobilization, hospital stay, fracture union, and Harris hip score. The minimum followup was 12 months (mean, 13 months; range, 12-18 months).
RESULTS: In the PFNA II group we encountered no impingement on the lateral cortex and no patients with lateral fragment or loss of reduction at insertion, whereas with the PFNA group, we had 10 and five cases, respectively. Fracture union occurred in all patients treated with PFNA II without mechanical failures. PFNA II cases were associated with a slightly shorter surgical time than PFNA cases (23 minutes versus 27 minutes, respectively).
CONCLUSION: PFNA II avoided lateral cortex impingement experienced with PFNA, providing fast and stable fixation of the unstable peritrochanteric fractures. LEVEL OF EVIDENCE: Level III, retrospective comparative study. See Guidelines for Authors for a complete description of levels of evidence.