title: Comparison of reliability of five patellar position indices at various stifle joint angles in pelvic limbs obtained from cadavers of red foxes (Vulpes vulpes).
abstract: OBJECTIVE
  To compare 5 patellar position indices at various stifle joint angles in cadavers of red foxes, determine measurement reliability, and assess the suitability of these indices for clinical use.
  
  
  METHODS
  Pelvic limbs from cadavers of 12 red foxes (Vulpes vulpes).
  
  
  METHODS
  Patellar position in each limb at 7 stifle joint angles (30° to 148°) was assessed by use of the Insall-Salvati (IS), modified Insall-Salvati (mIS), de Carvalho (dC), patellotrochlear (PT), and Blackburne-Peel (BP) indices.
  
  
  RESULTS
  Values for all indices varied significantly on the basis of joint angle, but for IS and mIS indices, this was minor and nonsignificant between 52° and 130° and between 52° and 148°, respectively. The dC index increased linearly, and PT and BP indices varied polynomially with increases in stifle joint angle. Stifle joint angles measured from radiographs agreed well with the goniometrically set stifle joint angles up to approximately 100° and diverged thereafter. Intraobserver and interobserver agreement was substantial for all indices, and IS index was the most precise.
  
  
  CONCLUSIONS
  IS and mIS index values were effectively independent of stifle joint angle, in contrast to dC, PT, and BP indices. The BP index varied nonsignificantly across a range of joint angles. To maximize angular accuracy, radiographs should not be obtained at joint angles > 100°. Although dC, PT, and BP indices appeared to be suitable for preoperative and postoperative evaluation of patellar position, BP index appeared to have the most promise for determination of patellar position in clinical applications.
authors.affiliation: Department of Small Animal Clinical Sciences, Faculty of Life Sciences, Copenhagen University, Frederiksberg C, Denmark. jami@life.ku.dk
authors.forename: James E
authors.initials: JE
authors.lastname: Miles
authors.forename: Dorte H
authors.initials: DH
authors.lastname: Nielsen
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; D015588:Observer Variation; D010329:Patella / Q000033:anatomy & histology*; D013264:Stifle / Q000033:anatomy & histology*