title: Auxiliary locking plate improves fracture stability and healing in intertrochanteric fractures fixated by intramedullary nail.
abstract: BACKGROUND
  Intertrochanteric fractures present a significant management challenge due to their low inherent stability. The objective of this study was to determine whether an auxiliary locking plate decreases interfragmentary motions and improves fracture healing in intertrochanteric fractures treated by intramedullary nail.
  
  
  METHODS
  Biomechanical tests and a clinical retrospective study in intertrochanteric to subtrochanteric nonunions were performed. Six synthetic femurs were osteotomized intertrochanterically and fixated with a long gamma nail and an additional locking compression plate. Mechanical tests were conducted that simulated the hip joint force during gait cycle. Following the initial test, the locking compression plate (LCP) was removed from each specimen and the test was repeated. Interfragmentary motions, strains on implants and osteosynthesis stiffness were determined. For the clinical part of the study, 13 intertrochanteric to subtrochanteric nonunions were treated with revisional long gamma nail and additional locking compression plate. Complications and time to union were determined.
  
  
  RESULTS
  Biomechanically, interfragmentary rotation was 48% smaller (P=0.047) and interfragmentary shear movement was 42% smaller (P=0.007) with locking compression plate. Strains on the nail decreased by 20-27% (P<0.027) and the osteosynthesis stiffness increased by 23% (P=0.005) with locking compression plate. Clinically, fracture healing was achieved in eleven out of 13 patients after 9.0months (range 4 to 22months).
  
  
  CONCLUSIONS
  The findings of our study indicate that auxiliary locked plating considerably improves biomechanical performance and results in successful healing of unstable intertrochanteric to subtrochanteric femur fractures.
authors.affiliation: Institute of Biomechanics, Trauma Center Murnau, Murnau, Germany. sebastian.eberle@bgu-murnau.de
authors.forename: Sebastian
authors.initials: S
authors.lastname: Eberle
authors.forename: Johannes
authors.initials: J
authors.lastname: Gabel
authors.forename: Sven
authors.initials: S
authors.lastname: Hungerer
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hoffmann
authors.forename: Robert
authors.initials: R
authors.lastname: Pätzold
authors.forename: Peter
authors.initials: P
authors.lastname: Augat
authors.forename: Volker
authors.initials: V
authors.lastname: Bühren
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001860:Bone Plates; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods*; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation / Q000379:methods; D017102:Fracture Healing; D005599:Fractures, Ununited / Q000503:physiopathology / Q000601:surgery*; D006620:Hip Fractures / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D012189:Retrospective Studies; D055815:Young Adult