title: Evaluation of functional outcome of the floating knee injury using multivariate analysis.
abstract: BACKGROUND
  The objective of this study is to evaluate significant contributing factors affecting the functional prognosis of floating knee injuries using multivariate analysis.
  
  
  METHODS
  A total of 68 floating knee injuries (67 patients) were treated at Kitasato University Hospital from 1986 to 1999. Both the femoral fractures and the tibial fractures were managed surgically by various methods. The functional results of these injuries were evaluated using the grading system of Karlström and Olerud. Follow-up periods ranged from 2 to 19 years (mean 50.2 months) after the original injury. We defined satisfactory (S) outcomes as those cases with excellent or good results and unsatisfactory (US) outcomes as those cases with acceptable or poor results. Logistic regression analysis was used as a multivariate analysis, and the dependent variables were defined as a satisfactory outcome or as an unsatisfactory outcome. The explanatory variables were predicting factors influencing the functional outcome such as age at trauma, gender, severity of soft-tissue injury in the femur and the tibia, AO fracture grade in the femur and the tibia, Fraser type (type I or type II), Injury Severity Score (ISS), and fixation time after injury (less than 1 week or more than 1 week) in the femur and the tibia.
  
  
  RESULTS
  The final functional results were as follows: 25 cases had excellent results, 15 cases good results, 16 cases acceptable results, and 12 cases poor results. The predictive logistic regression equation was as follows: Log 1-p/p = 3.12-1.52 x Fraser type - 1.65 x severity of soft-tissue injury in the tibia - 1.31 x fixation time after injury in the tibia - 0.821 x AO fracture grade in the tibia + 1.025 x fixation time after injury in the femur - 0.687 x AO fracture grade in the femur ( p=0.01). Among the variables, Fraser type and the severity of soft-tissue injury in the tibia were significantly related to the final result.
  
  
  CONCLUSIONS
  The multivariate analysis showed that both the involvement of the knee joint and the severity grade of soft-tissue injury in the tibia represented significant risk factors of poor outcome in floating knee injuries in this study.
authors.affiliation: Department of Orthopedic Surgery, School of Medicine, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan. yokopon@m2.ocv.ne.jp
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yokoyama
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: Shinichi
authors.initials: S
authors.lastname: Aoki
authors.forename: Ryuji
authors.initials: R
authors.lastname: Wakita
authors.forename: Masataka
authors.initials: M
authors.lastname: Uchino
authors.forename: Takashi
authors.initials: T
authors.lastname: Noumi
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Fukushima
authors.forename: Moritoshi
authors.initials: M
authors.lastname: Itoman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005264:Femoral Fractures / Q000150:complications / Q000601:surgery*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D017695:Soft Tissue Injuries / Q000209:etiology; D013978:Tibial Fractures / Q000150:complications / Q000601:surgery*; D016896:Treatment Outcome