• John C P Floyd, Robert V O'Toole, Alec Stall, Daren P Forward, Marjan Nabili, Daniel Shillingburg, Adam Hsieh, and Jason W Nascone.
• R Adams Cowley Shock Trauma Center, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
• J Orthop Trauma. 2009 Oct 1;23(9):628-33.

ObjectivesThe 95 degrees angled blade plate is an accepted standard for plating subtrochanteric femoral fractures but can be technically demanding and often requires extensive soft tissue exposure. Proximal femoral locking plates (PFLPs) have been developed for subtrochanteric and pertrochanteric fractures and are potentially easier to apply with less soft tissue dissection. Clinical experience has raised concerns regarding the strength of the PFLP. The purpose of our study was to compare the relative stability of two designs of PFLP with the 95 degrees angled blade plate under loads simulating the first 3 months of progressive weight bearing after fracture fixation.MethodsA comminuted subtrochanteric femoral fracture model was created with a 2-cm gap below the lesser trochanter in 15 synthetic femora. Fracture fixation of three plates (95 degrees angled blade plate [blade plate], the original version of the PFLP [O-PFLP], and the newest version of the PFLP [N-PFLP]), all manufactured by Synthes, Inc., Paoli, PA, was tested under progressive cyclic loading to reproduce progressive weight bearing during 3 months after fracture fixation. The force and number of cycles to reach 5 mm of displacement of the femoral head or failure of the implant were compared for each implant.ResultsN-PFLPs were significantly stiffer than blade plates and O-PFLPs (P = 0.01) and had a trend toward withstanding more cycles before failure (P = 0.06). All five O-PFLPs demonstrated catastrophic fatigue failure before completion of the protocol. One each of the blade plates and the N-PFLPs failed to complete the protocol (P = 0.04).ConclusionsIn the model studied, N-PFLPs were shown to have biomechanical properties that were at least equivalent to those of the blade plate. The fatigue failures of O-PFLPs mirrored our clinical experience. Use of the N-PFLP might be a viable alternative fixation method for comminuted subtrochanteric femoral fractures that currently are treated with blade plates.

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