title: Inclination of the patellar ligament in relation to flexion angle in stifle joints of dogs without degenerative joint disease.
abstract: OBJECTIVE
  To measure the angles between the patellar ligament and the tibial plateau and between the patellar ligament and the common tangent at the tibiofemoral contact point (TFCP) throughout the full range of motion of the stifle joint in dogs and determine the flexion angles at which the patellar ligament is perpendicular to the tibial plateau or to the common tangent.
  
  
  METHODS
  16 hind limbs from cadavers of 9 adult dogs without radiographically detectable degenerative joint disease.
  
  
  METHODS
  Mediolateral radiographic views of the stifle joints from full extension through full flexion were obtained (10 degrees increments). Angles between the tibial and femoral long axes (beta), between the patellar ligament and the tibial plateau gamma), and between the patellar ligament and the common tangent at TFCP (alpha) were measured. Data were analyzed via simple linear regression.
  
  
  RESULTS
  In canine stifle joints, angles gamma and alpha decreased linearly with increasing flexion (angle beta). The patellar ligament was perpendicular to the tibial plateau and perpendicular to the common tangent at the TFCP at 90 degrees and 110 degrees of flexion, respectively.
  
  
  CONCLUSIONS
  By use of the conventionally defined tibial plateau, data suggest that at approximately 90 degrees of flexion in stifle joints of dogs, shear force in the sagittal plane exerted on the proximal portion of the tibia shifts the loading from the cranial to the caudal cruciate ligament. Analyses involving the common tangent at the TFCP (a more anatomically representative reference point) identified this crossover point at approximately 110 degrees of joint flexion.
authors.affiliation: Tierklinik Dennler AG, Poststrasse 2, 8910 Affoltern am Albis, Switzerland.
authors.forename: Renate
authors.initials: R
authors.lastname: Dennler
authors.forename: Nicolas M
authors.initials: NM
authors.lastname: Kipfer
authors.forename: Slobodan
authors.initials: S
authors.lastname: Tepic
authors.forename: Michael
authors.initials: M
authors.lastname: Hassig
authors.forename: Pierre M
authors.initials: PM
authors.lastname: Montavon
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002102:Cadaver; D004285:Dogs / Q000033:anatomy & histology* / Q000502:physiology; D017847:Patellar Ligament / Q000033:anatomy & histology* / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D013264:Stifle / Q000033:anatomy & histology* / Q000502:physiology