title: Effects of tibial plateau angle and spacer thickness applied during in vitro canine total knee replacement on three-dimensional kinematics and collateral ligament strain.
abstract: OBJECTIVE
  To quantify the 3-D kinematics and collateral ligament strain of stifle joints in cadaveric canine limbs before and after cranial cruciate ligament transection followed by total knee replacement (TKR) involving various tibial plateau angles and spacer thicknesses.
  
  
  METHODS
  6 hemi-pelvises collected from clinically normal nonchondrodystrophic dogs (weight range, 25 to 35 kg).
  
  
  METHODS
  Hemi-pelvises were mounted on a modified Oxford knee rig that allowed 6 degrees of freedom of the stifle joint but prevented mechanical movement of the hip and tarsal joints. Kinematics and collateral ligament strain were measured continuously while stifle joints were flexed. Data were again collected after cranial cruciate ligament transection and TKR with combinations of 3 plateau angles (0°, 4°, and 8°) and spacer thicknesses (5, 7, and 9 mm).
  
  
  RESULTS
  Presurgical (ie, normal) stifle joint rotations were comparable to those previously documented for live dogs. After TKR, kinematics recorded for the 8°, 5-mm implant most closely resembled those of unaltered stifle joints. Decreasing the plateau angle and increasing spacer thickness altered stifle joint adduction, internal rotation, and medial translation. Medial collateral ligament strain was minimal in unaltered stifle joints and was unaffected by TKR. Lateral collateral ligament strain decreased with steeper plateau angles but returned to a presurgical level at the flattest plateau angle.
  
  
  CONCLUSIONS
  Among the constructs tested, greatest normalization of canine stifle joint kinematics in vitro was achieved with the steepest plateau angle paired with the thinnest spacer. Furthermore, results indicated that strain to the collateral ligaments was not negatively affected by TKR.
authors.affiliation: College of Engineering, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Baker
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Foutz
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Johnsen
authors.forename: Steven C
authors.initials: SC
authors.lastname: Budsberg
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee / Q000662:veterinary*; D001696:Biomechanical Phenomena; D002102:Cadaver; D017885:Collateral Ligaments / Q000502:physiology*; D004285:Dogs / Q000502:physiology / Q000601:surgery*; D021621:Imaging, Three-Dimensional / Q000662:veterinary; D009068:Movement; D016059:Range of Motion, Articular; D012399:Rotation; D013264:Stifle / Q000601:surgery*; D013977:Tibia / Q000601:surgery*