title: Effect of tibial tuberosity advancement on the contact mechanics and the alignment of the patellofemoral and femorotibial joints.
abstract: OBJECTIVE
  To evaluate the effect of tibial tuberosity advancement (TTA) on patellofemoral (PF) contact mechanics, and alignment of the PF and femorotibial (FT) joints in cranial cruciate ligament (CrCL)-deficient stifles of dogs.
  
  
  METHODS
  Ex vivo biomechanical study.
  
  
  METHODS
  Unpaired cadaveric hind limbs (n=9).
  
  
  METHODS
  Digital pressure sensors placed in the PF joint were used to measure contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135°. The FT and PF poses were obtained using a 2-dimensional computer digitization technique. Each specimen was tested under normal, CrCL-deficient, and TTA-treated conditions. Data was normalized and analyzed, after testing for normality by Wilk-Shapiro, using 1 sample T-test, paired T-test, and ANOVA; P≤.05 was considered significant. Bonferroni's correction was used when needed.
  
  
  RESULTS
  A significant cranioproximal tibial displacement and increase in patellar tilt were found in the CrCL-deficient joints. Both FT and PF alignments were restored after TTA. Contact areas and peak pressure did not vary between conditions. Peak pressure location displaced proximally from intact to CrCL-deficient condition and returned to normal after TTA. Total force measured in the CrCL-deficient stifle and TTA conditions were significantly lower than in the control.
  
  
  CONCLUSIONS
  TTA restored the normal FT and PF alignment, and reduced the retropatellar force by about 20%.
authors.affiliation: Clinic for Small Animal Surgery, Vetsuisse-Faculty University of Zurich, Zurich, Switzerland. tguerrero@sgu.edu
authors.forename: Tomás G
authors.initials: TG
authors.lastname: Guerrero
authors.forename: Antonio
authors.initials: A
authors.lastname: Pozzi
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dunbar
authors.forename: Nicolas
authors.initials: N
authors.lastname: Kipfer
authors.forename: Michael
authors.initials: M
authors.lastname: Haessig
authors.forename: Mary
authors.initials: M
authors.lastname: Beth Horodyski
authors.forename: Pierre M
authors.initials: PM
authors.lastname: Montavon
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001696:Biomechanical Phenomena; D002102:Cadaver; D004285:Dogs / Q000033:anatomy & histology* / Q000502:physiology*; D010027:Osteotomy / Q000379:methods / Q000662:veterinary*; D013264:Stifle / Q000033:anatomy & histology* / Q000502:physiology*; D013977:Tibia / Q000601:surgery