title: Measurement repeatability of tibial tuberosity-trochlear groove offset distance in red fox (Vulpes vulpes) cadavers.
abstract: OBJECTIVE
  To describe CT image reconstruction criteria for measurement of the tibial tuberosity-trochlear groove (TT-TG) offset distance, evaluate intra- and inter-reconstruction repeatability, and identify key sources of error in the measurement technique, as determined in vulpine hind limbs.
  
  
  METHODS
  12 red fox (Vulpes vulpes) cadavers.
  
  
  METHODS
  CT images of each hind limb in intact cadavers were obtained; at 1-week intervals, 3 reconstructions were performed that were based on 1 plane passing through the centers of the femoral head and medial condyle and parallel to the caudal femoral condyles, 1 plane aligned with the femoral trochlea, and a third orthogonal plane. Randomized and anonymized reconstructions were assessed for TT-TG offset distance with a single-image technique by 1 observer, and inter-reconstruction repeatability and intra- and inter-reconstruction measurement repeatability were assessed via the repeatability coefficient and intraclass correlation coefficient.
  
  
  RESULTS
  Multiplanar reconstructions of hind limb images were repeatedly made to within a few degrees of each other. Intra- and inter-reconstruction repeatability for TT-TG offset distance measurement was good. Repeatability was most affected by accurate identification of the tibial tuberosity and femoral trochlea landmarks.
  
  
  CONCLUSIONS
  Results obtained from vulpine hind limb CT images indicated that reconstructions can be made with a high degree of repeatability when based on strictly defined and applied criteria. The TT-TG offset distance has potential as an objective assessment of alignment of the distal portion of the quadriceps mechanism; its use as an aid in case selection for corrective femoral osteotomy among dogs with medial patellar luxation warrants investigation.
authors.affiliation: Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg C, Denmark. jami@sund.ku.dk
authors.forename: James E
authors.initials: JE
authors.lastname: Miles
authors.forename: Bente R
authors.initials: BR
authors.lastname: Jensen
authors.forename: Jolle
authors.initials: J
authors.lastname: Kirpensteijn
authors.forename: Eiliv L
authors.initials: EL
authors.lastname: Svalastoga
authors.forename: Thomas
authors.initials: T
authors.lastname: Eriksen
mesh_terms: D000818:Animals; D002102:Cadaver; D005260:Female; D005589:Foxes / Q000033:anatomy & histology*; D008297:Male; D013264:Stifle / Q000033:anatomy & histology*; D013977:Tibia / Q000033:anatomy & histology*