title: Visual estimation of radioulnar incongruence in dogs using three-dimensional image rendering: an in vitro study based on computed tomographic imaging.
abstract: OBJECTIVE
  To determine the sensitivity and specificity of visual estimation of radioulnar incongruence (RUI) in the canine elbow by use of 3-dimensional (3D) image rendering.
  
  
  METHODS
  Experimentally induced negative and positive RUI.
  
  
  METHODS
  Canine (>20 kg) cadaveric right thoracic limbs (n=8).
  
  
  METHODS
  Radial shortening and lengthening of 1 and 2 mm were performed extending an established surgical in vitro model of RUI. Based on transverse computed tomographic (CT) scans of each radioulnar conformation, the subchondral radioulnar joint surface was reconstructed and visualized. A total of 64 3D models of RUI were blindly evaluated in a random manner by 3 independent observers. RUI was estimated subjectively at 1 mm precisely (-2, -1, 0, +1, +2) by visual inspection of the 3D models.
  
  
  RESULTS
  Median sensitivity for identifying an incongruent joint was 0.86. Median specificity for identification of a congruent joint was 0.77. Analyzing the data only in respect to a congruent joint versus one with a shortened radius (positive RUI) resulted in a median sensitivity of 0.82, and a median specificity of 1.00. Interobserver agreement was 0.87. Repeatability was 0.96.
  
  
  CONCLUSIONS
  Estimation of positive and negative RUI based on 3D surface models of the radioulnar articulation mimics gross inspection in a noninvasive manner, the latter being the ultimate gold standard for definitive diagnosis of any radioulnar step. The proposed technique is precise, reliable, and repeatable in vitro.
  
  
  CONCLUSIONS
  Preoperative estimation of the type and degree of RUI is the basis for deciding which type of corrective or modifying osteotomy might be best suited to restore normal joint loads in vivo.
authors.affiliation: Department of Small Animal Medicine, University of Leipzig, Leipzig, Germany. boettcher@kleintierklinik.uni-leipzig.de
authors.forename: Peter
authors.initials: P
authors.lastname: Böttcher
authors.forename: Hinnerk
authors.initials: H
authors.lastname: Werner
authors.forename: Eberhard
authors.initials: E
authors.lastname: Ludewig
authors.forename: Vera
authors.initials: V
authors.lastname: Grevel
authors.forename: Gerhard
authors.initials: G
authors.lastname: Oechtering
mesh_terms: D000818:Animals; D004285:Dogs; D005552:Forelimb / Q000033:anatomy & histology*; D007596:Joints / Q000033:anatomy & histology*; D016059:Range of Motion, Articular; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000662:veterinary*