[Mechanical evaluation of a ligament fixation system for ACL reconstruction at the tibia in a canine cadaver model].
OBJECTIVE
Excellent fixation of an artificial ligament in bone is mandatory for initial stability. ACL reconstruction with the LARS artificial ligament may fail if anchorage to bone is inadequate. The weak metaphyseal bone of the proximal tibia is prone to inadequate fixation. This study evaluates the initial mechanical stability of two techniques with an interference screw on the tibial side of an ACL reconstruction with the LARS ligament.


METHODS
Six left tibias were obtained from 1 to 3 year old mongrel dog weighing 20 to 26 kg. ACL straight line reconstruction according to the technique described by J.P. Laboureau was performed with a 4.5 mm drill. Two tunnels were created in the tibia, one oblique and one transverse, the latter 2 cm below the former. Reconstruction was done with a 30-fiber LARS ligament and a 5.2 mm x 15 mm conical titanium cannulated interference screw. Group I had an interference screw in the oblique tunnel and group II had an interference screw in the transverse tunnel. Pull-out tests were performed parallel to the oblique tunnel on an Instron 8521 machine at a speed of 5 mm per minute until failure. The oblique tunnel was tested first then the transverse tunnel.


RESULTS
Group I (n = 6): sliding value = 238 +/- 115 N. Group II (n = 6): sliding value = 998 +/- 148 N. This is statistically significant (p < 0.001, student t-test).


CONCLUSIONS
One interference screw in a transverse tibial tunnel for ACL reconstruction with the LARS ligament is 4 times more resistant on loading and impact than an oblique screw.
Leduc
S
S
Service d'Orthopédie, CHUM, Montréal, Québec, Canada.
Yahia
L
L
Boudreault
F
F
Fernandes
J C
JC
Duval
N
N
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D001863:Bone Screws; D002102:Cadaver; D004195:Disease Models, Animal; D004285:Dogs; D020007:Implants, Experimental; D007593:Joint Instability / Q000209:etiology; D007719:Knee Joint; D008422:Materials Testing; D011091:Polyesters; D019919:Prosthesis Implantation / Q000379:methods*; D012421:Rupture; D013718:Tensile Strength; D013977:Tibia / Q000601:surgery*
D011091:Polyesters
Evaluation mécanique d'un système de fixation ligamentaire pour la reconstruction du LCA au niveau du tibia sur un modèle canin cadavérique.