title: Unstable pertrochanteric femoral fractures.
abstract: BACKGROUND
  Fractures in the trochanteric region of the femur are classified as AO/OTA 31-A, as they are extracapsular. This report analyzes the relatively rare 31-A3 fracture, which has also been referred to as an "intertrochanteric femur fracture with subtrochanteric extension," "reverse obliquity intertrochanteric femur fracture," "unstable intertrochanteric femur fracture," or a "subtrochanteric femur fracture." The A3 fracture is characterized by having a fracture line exiting the lateral femoral cortex distal to the vastus ridge. Possible fixation constructs include compression hip screws, intramedullary hip screws, trochanteric intramedullary nails, cephalomedullary antegrade intramedullary nails, and 95 degrees plates. Most reports investigating 31-A fractures do not describe the 31-A3 fracture. For this analysis, only reports clearly indicating that the fracture treated was a 31-A3 were included. It should be understood that this approach therefore excludes reports on generic "subtrochanteric fractures" or "intertrochanteric fractures," some of which may have been 31-A3 fractures.
  
  
  OBJECTIVE
  To determine the effect of fixation technique for the AO/OTA 31-A3 fracture on rates of union, infection, risk of reoperation, and functional outcomes.
authors.affiliation: Division of Orthopaedic Trauma, Department of Orthopaedics and Rehabilitation, Vanderbilt University, Nashville, TN 37212, USA. philip.kregor@vanderbilt.edu
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Kregor
authors.forename: William T
authors.initials: WT
authors.lastname: Obremskey
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Kreder
authors.forename: Marc F
authors.initials: MF
authors.lastname: Swiontkowski
mesh_terms: D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006620:Hip Fractures / Q000145:classification / Q000601:surgery*; D006801:Humans