title: Ipsilateral intact fibula as a predictor of tibial plafond fracture pattern and severity.
abstract: BACKGROUND
  The objective of this study was to determine whether there is a difference in fracture pattern and severity of comminution between tibial plafond fractures with and without associated fibular fractures using computed tomography (CT). We hypothesized that the presence of an intact fibula was predictive of increased tibial plafond fracture severity.
  
  
  METHODS
  This was a case control, radiographic review performed at a single level I university trauma center. Between November 2007 and July 2011, 104 patients with 107 operatively treated tibial pilon fractures and preoperative CT scans were identified: 70 patients with 71 tibial plafond fractures had associated fibular fractures, and 34 patients with 36 tibial plafond fractures had intact fibulas. Four criteria were compared between the 2 groups: AO/OTA classification of distal tibia fractures, Topliss coronal and sagittal fracture pattern classification, plafond region of greatest comminution, and degree of proximal extension of fracture line.
  
  
  RESULTS
  The intact fibula group had greater percentages of AO/OTA classification B2 type (5.5 vs 0, P = .046) and B3 type (52.8 vs 28.2, P = .013). Conversely, the percentage of AO/OTA classification C3 type was greater in the fractured fibula group (53.5 vs 30.6, P = .025). Evaluation using the Topliss sagittal and coronal classifications revealed no difference between the 2 groups (P = .226). Central and lateral regions of the plafond were the most common areas of comminution in fractured fibula pilons (32% and 31%, respectively). The lateral region of the plafond was the most common area of comminution in intact fibula pilon fractures (42%). There was no statistically significant difference (P = .71) in degree of proximal extension of fracture line between the 2 groups.
  
  
  CONCLUSIONS
  Tibial plafond fractures with intact fibulas were more commonly associated with AO/OTA classification B-type patterns, whereas those with fractured fibulas were more commonly associated with C-type patterns. An intact fibula may be predictive of less comminution of the plafond. The lateral and central regions of the plafond were the most common areas of comminution in tibial plafond fractures, regardless of fibular status.
  
  
  METHODS
  Level III, case control study.
authors.affiliation: University of Southern California, Los Angeles, CA.
authors.forename: Pamela C
authors.initials: PC
authors.lastname: Luk
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Charlton
authors.forename: Jackson
authors.initials: J
authors.lastname: Lee
authors.forename: David B
authors.initials: DB
authors.lastname: Thordarson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005596:Fractures, Closed / Q000000981:diagnostic imaging / Q000601:surgery; D018460:Fractures, Comminuted / Q000601:surgery; D005597:Fractures, Open / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013978:Tibial Fractures / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: case-control; computed tomography; fracture severity; intact fibula; tibial plafond fractures