title: Radiographic quantitative assessment of cranial tibial subluxation before and after tibial plateau leveling osteotomy in dogs.
abstract: OBJECTIVE
  To determine the influence of stifle joint flexion angle, cranial cruciate ligament (CrCL) integrity, tibial plateau leveling osteotomy (TPLO), and cranial tibial subluxation on the distance between the location of the origin and insertion of the CrCL (CrCL(d)) in dogs.
  
  
  METHODS
  4 pairs of pelvic limbs from adult dog cadavers weighing 23 to 34 kg. Procedures-Mediolateral projection radiographs of each stifle joint were obtained with the joint flexed at 90°, 105°, 120°, 135°, and 150°. Radiopaque markers were then placed at the sites of origin and insertion of the CrCL. Afterward, radiography was repeated in the same manner, before and after CrCL transection, with and without TPLO. Following CrCL transection, radiographs were obtained before and after inducing overt cranial tibial subluxation. Interobserver variation in measuring the CrCL(d) without fiduciary markers was assessed. The effect of CrCL integrity, cranial tibial subluxation, flexion angle, and TPLO on CrCL(d) was also determined.
  
  
  RESULTS
  Interobserver agreement was strong, with an intraclass correlation coefficient of 0.859. The CrCL(d) was significantly shorter (< 1 mm) at 90° of flexion; otherwise, flexion angle had no effect on CrCL(d). Cranial tibial subluxation caused a 25% to 40% increase in CrCL(d). No effect of TPLO on CrCL(d) was found, regardless of CrCL integrity, forced stifle joint subluxation, or flexion angle.
  
  
  CONCLUSIONS
  Overt cranial tibial subluxation in CrCL-deficient stifle joints can be detected on mediolateral projection radiographs by comparing CrCL(d) on neutral and stressed joint radiographs at joint angles between 105° and 150°, regardless of whether a TPLO has been performed.
authors.affiliation: Comparative Orthopaedics Biomechanics Laboratory and Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA. stankim@ufl.edu
authors.forename: Stanley E
authors.initials: SE
authors.lastname: Kim
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Lewis
authors.forename: Antonio
authors.initials: A
authors.lastname: Pozzi
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Seibert
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Winter
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001175:Arthrography / Q000662:veterinary*; D004285:Dogs; D005269:Femur / Q000293:injuries / Q000601:surgery; D010027:Osteotomy / Q000379:methods / Q000662:veterinary*; D013264:Stifle / Q000293:injuries / Q000601:surgery; D013977:Tibia / Q000293:injuries / Q000601:surgery