Proximal Femoral Nail Antirotation versus Gamma3 nail for intramedullary nailing of unstable trochanteric fractures. A randomised comparative study
Introduction
Trochanteric (intertrochanteric) fractures are the second most common fractures of the proximal femur after femoral neck fractures, with an annual incidence ranging between 50 and 450 per 100,000 population.1, 2, 3, 4, 5, 6, 7 Common treatment options include intramedullary nailing with either the Gamma nail or Proximal Femoral Nail (PFN), both of which represent the most commonly used implants for the treatment of trochanteric fractures worldwide.8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19
The Gamma was developed for intramedullary fixation of highly volatile AO type 31-A2/A3 hip fractures. While positive outcomes have been reported,20 postoperative femoral shaft fractures have emerged as the key implant-related complication with rates of up to 12%.21 A further problem with fixation of complex femoral fractures involves the potential secondary rotation of the head–neck fragment followed by collapse at the fracture site and cut-out, which still represent characteristic device-related adverse events. The reported cut-out rates range from 4% to 8%.20, 21, 22
The principal design of the PFN was based on modifications to overcome the known limitations and potential sources of complications of the Gamma device. The PFN has a smaller diameter and fluted tip to reduce bone stress and the subsequent risk of shaft fractures, a single distal locking screw placed more proximally for dynamic or static locking to maintain the stiffness of the construct, and a smaller dynamic screw inserted through the most proximal part of the femoral neck to prevent rotation of the head-neck fragment, and to reduce the incidence of implant cutout.20, 23, 24, 25 Further modifications of the PFN led to the Proximal Femoral Nail Antirotation device. A single femoral neck blade element replaced the previous dual femoral head–neck screw system of the PFN. This novel twisted blade tip element is loosely connected to an olive-shaped shaft as it passes through the nail. After insertion, the connection between the two parts is tightened by an internal locking system, thereby preventing rotational movement of the screw. This antirotation property is believed to enhance the primary stiffness of the construct (i.e., anchorage strength of the implant–bone complex), preventing residual micro-motion and subsequent loosening of components, and thereby to affect the rates of implant-related complications and the need for surgical revision.
The primary aim of this study was to compare the risk of fracture fixation failure of the PFNA with the third generation Gamma nail, Gamma3®, using a randomised controlled design.
Section snippets
Patients and methods
A multicentre, prospective randomised controlled study was conducted including patients with unstable trochanteric fractures treated with intramedullary nail fixation. The interventions were performed by surgeons from six Spanish hospitals. The Ethics Committees at the different hospitals approved this study.
Patients with an isolated, unstable, closed or type 1 open trochanteric fracture (i.e., an AO type 31-A2 or 31-A3 fracture) were included if they were aged 55 years or older, provided
Surgery results
The mean time between trauma and PFNA surgery of 2±1 days was similar to the mean time taken prior to surgery for the Gamma3 group (2±1 days) (p = 0.228).
The mean time taken for PFNA surgery from incision to closure was also similar to that taken for Gamma3 surgery (35±10 vs. 37±10 min) (p = 0.445). The median fluoroscopy time during PFNA surgery was 55 s (range: 10–300 s), which was similar to the median time of 48 s (range: 5–110 s) required for Gamma3 surgery (p = 0.267). There was no
Discussion
In the present study, the results with the PFNA and Gamma3 nails for the treatment of unstable proximal femoral fractures in patients older than 55 years of age showed no important differences in terms of pain, functional outcomes and complication rates. The principal endpoint of this study was to compare the fracture fixation complication rates between the PFNA and the Gamma3 nail devices. These complications were principally the impaction of the fracture area, the cut-out, and the fracture of
Disclosure statement
Data collection and data analysis was supported by the AO Foundation and a financial grant from Synthes, GmbH, Switzerland. For this reason the study was designed in cooperation with the AO Foundation and Synthes. The authors state that there are no conflicts of interest that could inappropriately influence their work.
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