title: Mono- versus polyaxial locking plates in distal femur fractures: a prospective randomized multicentre clinical trial.
abstract: OBJECTIVE
  Treatment of complex fractures of the distal femur utilizing monoaxial locking plates (e.g. Less Invasive Stabilisation System, LISS®, Synthes) is considered to be superior to conventional plating systems. Due to the limitation that the thread forces the screw into pre-determined positions, modifications have been made to allow screw positioning within a range of 30° (Non Contact Bridging, NCB®-DF, Zimmer). For the first time, this multicenter prospective randomized clinical trial (RCT) investigates the outcome of LISS® vs. NCB®-DF treatment following complex fractures of the distal femur.
  
  
  METHODS
  Since June 2008, 27 patients with a fracture of the distal femur (AO ASIF 33-A-C and periprosthetic fractures) were enrolled in this study by four university trauma centres in southern Germany. Clinical (e.g. range of motion, Oxford knee score, Tegner score) and radiological (e.g. axis deviation, secondary loss of realignment) follow-ups were conducted one and six weeks, as well as three, six, and 12 months after the operation.
  
  
  RESULTS
  This study comprises data of 27 patients (8 male, 19 female; 15 NCB®-DF, 12 LISS®). Polyaxial osteosynthesis using the NCB® system tended to result in better functional knee scores and a higher range of motion. Interestingly, fracture union tended to be more rapid using the polyaxial plating system.
  
  
  CONCLUSIONS
  We present the analysis of a multicenter prospective RCT to compare the monoaxial LISS® vs. the polyaxial NCB®-DF treatment following complex fractures of the distal femur. NCB®-DF treatment tended to result in better functional and radiological outcomes than LISS® treatment.
  
  
  METHODS
  Level I.
authors: Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany, Marc.Hanschen@mri.tum.de.
authors: Marc
authors: M
authors: Hanschen
authors: Ina M
authors: IM
authors: Aschenbrenner
authors: Kai
authors: K
authors: Fehske
authors: Sonja
authors: S
authors: Kirchhoff
authors: Leonhard
authors: L
authors: Keil
authors: Boris M
authors: BM
authors: Holzapfel
authors: Sebastian
authors: S
authors: Winkler
authors: Bernd
authors: B
authors: Fuechtmeier
authors: Rainer
authors: R
authors: Neugebauer
authors: Sven
authors: S
authors: Luehrs
authors: Ulrich
authors: U
authors: Liener
authors: Peter
authors: P
authors: Biberthaler
mesh_terms: D000368:Aged; D001860:Bone Plates; D005260:Female; D005264:Femoral Fractures / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D057068:Periprosthetic Fractures / Q000601:surgery*; D011446:Prospective Studies; D016059:Range of Motion, Articular