title: Magnetic resonance measurements of the deviation of the angle of force generated by contraction of the quadriceps muscle in dogs with congenital patellar luxation.
abstract: OBJECTIVE
  To measure the quadriceps angle (Q-angle) in dogs with congenital patellar luxation using magnetic resonance (MR) methods.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Thirty-eight client-owned dogs.
  
  
  METHODS
  Thirty-eight dogs were examined and placed into the following groups based on the degree of patellar instability: normal, grade I, grade II, and grade III. MR images of 37 pelvic limbs without patellar instability, 33 pelvic limbs with patellar luxation, and 6 limbs with cranial cruciate ligament (CrCL) rupture were made. The Q-angle was calculated using trigonometric methods based on MR images. Limbs with patellar luxation were compared with normal stifles and stifle with other disorders.
  
  
  RESULTS
  The average Q-angle of the normal group was 10.5 degrees (24.9 degrees to -2.0 degrees ). The grade I group had an average Q-angle of 12.2 degrees (28.8 degrees to 2 degrees ), the grade II group 24.3 degrees (44.6 degrees to 7.7 degrees ), and the grade III group 36.6 degrees (51.4 degrees to 15.6 degrees ). The average Q-angle of limbs with an isolated CrCL rupture was 19.3 degrees (34.7 degrees to 3.9 degrees ).
  
  
  CONCLUSIONS
  MR images can be used to make exact calculations of the Q-angle.
  
  
  CONCLUSIONS
  MR images can be used to quantify the degree of patellar luxation.
authors.affiliation: Department of Small Animals, Clinic Benjamin Franklin, 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
authors.initials: M
authors.lastname: Garner
authors.forename: H
authors.initials: H
authors.lastname: Waibl
authors.forename: L
authors.initials: L
authors.lastname: Brunnberg
mesh_terms: D000818:Animals; D001947:Breeding; D004283:Dog Diseases / Q000151:congenital / Q000473:pathology*; D004285:Dogs / Q000502:physiology*; D006614:Hindlimb / Q000473:pathology / Q000502:physiology; D004204:Joint Dislocations / Q000151:congenital / Q000473:pathology / Q000662:veterinary*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D009119:Muscle Contraction / Q000502:physiology; D010329:Patella / Q000473:pathology*; D011446:Prospective Studies