title: Mechanical strength of four allograft fixation techniques for ruptured cranial cruciate ligament repair in dogs.
abstract: OBJECTIVE
  To test ex vivo mechanical properties of 4 allograft fixation techniques for cranial cruciate ligament (CCL) replacement.
  
  
  METHODS
  30 stifle joints from canine cadavers.
  
  
  METHODS
  CCL-deficient stifle joints repaired by 1 of 4 techniques (n = 6/group) and CCL-intact stifle joints (control group; 6) were mechanically tested. Three repair techniques involved a patella-patella ligament segment (PPL) allograft: a tibial and femoral interference screw (PPL-2S), a femoral interference screw and the patella seated in a tapering bone tunnel in the tibia (PPL-1S), or addition of a suture and a bone anchor to the PPL-1S (PPL-SL). The fourth technique involved a deep digital flexor tendon (DDFT) allograft secured with transverse femoral fixation and stabilized with a tibial interference screw and 2 spiked washers on the tibia (DDFT-TF). The tibia was axially loaded at a joint angle of 135°. Loads to induce 3, 5, and 10 mm of femoral-tibia translation; stiffness; and load at ultimate failure with the corresponding displacement were calculated. Group means were compared with a multivariate ANOVA.
  
  
  RESULTS
  Mean ± SD load for the intact (control) CCL was 520.0 ± 51.3 N and did not differ significantly from the load needed to induce 3 mm of femoral-tibial translation for fixation techniques PPL-SL (422.4 ± 46.3 N) and DDFT-TF (654.2 ± 117.7 N). Results for the DDFT-TF were similar to those of the intact CCL for all outcome measures.
  
  
  CONCLUSIONS
  The DDFT-TF yielded mechanical properties similar to those of intact CCLs and may be a viable technique to test in vivo.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996.
authors.forename: Jeffery J
authors.initials: JJ
authors.lastname: Biskup
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Balogh
authors.forename: Kevin H
authors.initials: KH
authors.lastname: Haynes
authors.forename: Andy L
authors.initials: AL
authors.lastname: Freeman
authors.forename: Michael G
authors.initials: MG
authors.lastname: Conzemius
mesh_terms: D064591:Allografts / Q000601:surgery*; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001696:Biomechanical Phenomena; D002102:Cadaver; D004283:Dog Diseases / Q000209:etiology / Q000601:surgery*; D004285:Dogs; D010329:Patella / Q000601:surgery; D017847:Patellar Ligament / Q000601:surgery; D013264:Stifle / Q000601:surgery*