title: The correlation of canine patellar luxation and the anteversion angle as measured using magnetic resonance images.
abstract: Measurements from magnetic resonance (MR) images can be used to examine the anteversion angle (AT-angle) and its influence on the lateromedial or mediolateral luxating forces on the patella. The AT-angle of the femoral neck was measured with the aid of MR imaging in 45 pelvic limbs without patellar instability, in 33 limbs with patellar luxation and in 6 limbs with rupture of the cranial cruciate ligament. The limbs with medial patellar luxation were divided into three groups based on clinical examination. The mean (range) AT-angle was 7.6 degrees (0 degrees to 24 degrees) in the "normal" group, 8.6 degrees (-10 degrees to 29 degrees) in the group "grade II," and -0.4 degrees in the group "grade III" (-28 degrees to 12 degrees). A mean (range) AT-angle of 4.8 (-4 degrees to 11 degrees) was measured in the pelvic limbs with rupture of the cranial cruciate ligament. Compared to literature that described AT-angles based on radiographs of normal limbs, reduced AT-angles were found in this study due to different lines of measurement of the femoral neck. This study documents that the AT-angle of the femoral neck does not influence patellar instability. This study also demonstrates that MR images can be used to make exact measurements of the canine AT-angle that represent the true anatomy of the femoral neck.
authors.affiliation: Department of Small Animals, Free University of Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kaiser
authors.forename: D
authors.initials: D
authors.lastname: Cornely
authors.forename: W
authors.initials: W
authors.lastname: Golder
authors.forename: M T
authors.initials: MT
authors.lastname: Garner
authors.forename: K J
authors.initials: KJ
authors.lastname: Wolf
authors.forename: H
authors.initials: H
authors.lastname: Waibl
authors.forename: L
authors.initials: L
authors.lastname: Brunnberg
mesh_terms: D000818:Animals; D004285:Dogs / Q000293:injuries*; D004204:Joint Dislocations / Q000000981:diagnostic imaging / Q000662:veterinary*; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D010329:Patella / Q000000981:diagnostic imaging* / Q000293:injuries*; D011859:Radiography