title: Knee injuries in severe trauma patients: a trauma registry study in 3.458 patients.
abstract: BACKGROUND
  Purpose of the presented study is to answer the following questions: Are knee injuries associated with trauma mechanisms or concomitant injuries? Do injuries of the knee region aggravate treatment costs or prolong hospital stay in polytraumatized patients?
  
  
  METHODS
  A retrospective analysis including 29.779 severely injured patients (Injury Severity Score [greater than or equal to] 16) from the Trauma Registry of the German Society for Trauma Surgery database (1993-2008) was conducted. Patients were subdivided into two groups; the "Knee" group (n=3.458, 11.6% of all patients) including all multiple trauma patients with knee injuries, and the "Non Knee" group (n=26.321) including the remaining patients. Patients with knee injuries were slightly younger, less often male gender and had a significantly increased ISS.
  
  
  RESULTS
  Patients in the Knee group suffered significantly more traffic accidents compared to the Non Knee group (82% vs. 52%, p<0.001). These injuries were more often caused by car or motorbike accidents. Severe thoracic and limb injuries (AIS[greater than or equal to]3) were more frequently found in the Knee group (p<0.001) while head injury was distributed equally. The overall hospital stay, ICU stay, and treatment costs were significantly higher for the Knee group (38.1 vs. 25.5 days, 15.2 vs. 11.4 days, 40,116 vs. 25,336 Euro, respectively; all p<0.001).
  
  
  CONCLUSIONS
  Traffic accidents are associated with an increased incidence of knee injuries than falls or attempted suicides. Furthermore, severe injuries of the limbs and chest are more common in polytraumatized patients with knee injuries. At last, treatment of these patients is prolonged and consequently more expensive.
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, Hannover, 30625, Germany.
authors.forename: Hagen
authors.initials: H
authors.lastname: Andruszkow
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, Hannover, 30625, Germany.
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Liodakis
authors.affiliation: Institute for Research in Operative Medicine (IFOM), Cologne-Merheim Medical Center, University Witten-Herdecke, Cologne, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Lefering
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, Hannover, 30625, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Krettek
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, Hannover, 30625, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Hildebrand
authors.affiliation: Trauma Department, Hannover Medical School, Carl-Neuberg-Straße 1, Hannover, 30625, Germany.
authors.forename: Carl
authors.initials: C
authors.lastname: Haasper