title: Quantitative 3-dimensional computed tomography analysis of olecranon fractures.
abstract: OBJECTIVE
  Olecranon fractures have variable size of the proximal fragment, patterns of fragmentation, and subluxation of the ulnohumeral joint that might be better understood and categorized on the basis of quantitative 3-dimensional computed tomography analysis. Mayo type I fractures are undisplaced, Mayo type II are displaced and stable, and Mayo type III are displaced and unstable. The last is categorized into anterior and posterior dislocations. The purpose of this study was to further clarify fracture morphology between Mayo type I, II, and III fractures.
  
  
  METHODS
  Three-dimensional models were created for a consecutive series of 78 patients with olecranon fractures that were evaluated with computed tomography. We determined the total number of fracture fragments, the volume and articular surface area of each fracture fragment, and the degree of displacement of the most proximal olecranon fracture fragment.
  
  
  RESULTS
  Displaced olecranon fractures were more comminuted than nondisplaced fractures (P = .02). Displaced fractures without ulnohumeral subluxation were smallest in terms of both volume (P < .001) and articular surface involvement (P < .001) of the most proximal olecranon fracture fragment. There was no difference in average displacement of the proximal fragment between displaced fractures with and without ulnohumeral subluxation (P = .74). Anterior olecranon fracture-dislocations created more displaced (P = .04) and smaller proximal fragments than posterior fracture-dislocations (P = .005), with comparable fragmentation on average (P = .60).
  
  
  CONCLUSIONS
  The ability to quantify volume, articular surface area, displacement, and fragmentation using quantitative 3-dimensional computed tomography should be considered when increased knowledge of fracture morphology and fracture patterns might be useful.
authors.affiliation: Orthopaedic Hand and Upper Extremity Service, Massachusetts General Hospital-Harvard Medical School, Boston, MA, USA.
authors.forename: Bart
authors.initials: B
authors.lastname: Lubberts
authors.affiliation: Orthopaedic Hand and Upper Extremity Service, Massachusetts General Hospital-Harvard Medical School, Boston, MA, USA.
authors.forename: Stein
authors.initials: S
authors.lastname: Janssen
authors.affiliation: Orthopaedic Hand and Upper Extremity Service, Massachusetts General Hospital-Harvard Medical School, Boston, MA, USA.
authors.forename: Jos
authors.initials: J
authors.lastname: Mellema
authors.affiliation: Orthopaedic Hand and Upper Extremity Service, Massachusetts General Hospital-Harvard Medical School, Boston, MA, USA; Department of Surgery and Perioperative Care, Dell Medical School-The University of Texas at Austin, Austin, TX, USA. Electronic address: david.ring@austin.utexas.edu.
authors.forename: David
authors.initials: D
authors.lastname: Ring
mesh_terms: D000368:Aged; D004551:Elbow Joint / Q000000981:diagnostic imaging; D005260:Female; D018460:Fractures, Comminuted / Q000000981:diagnostic imaging; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D004204:Joint Dislocations / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D056740:Olecranon Process / Q000000981:diagnostic imaging* / Q000293:injuries*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014458:Ulna Fractures / Q000145:classification / Q000000981:diagnostic imaging*
keywords: Computed tomography; Mayo classification; fracture; olecranon; quantitative