Summary
Objective
To measure the change of length patterns of nine different simulated anterior cruciate
ligament (ACL) reconstructions in the canine and human knee.
Procedures
Six fresh-frozen canine cadaver knees and six fresh-frozen human cadaver knees were
used in this study. All of the soft tissues were removed from each cadaver knee, leaving
the menisci, collateral ligaments and cruciate ligaments intact. After fixation of
the femur to a custom-made frame, the ACL was excised. Three tunnels were made each
at the ACL origin and insertion, making possible nine reconstruction combinations.
A modified intra-articular technique was used to measure change of length, in mm,
of each ACL reconstruction through a range of motion of 0 degrees (full extension)
to 135 degrees of flexion. A rankorder list of reconstruction combinations was determined.
The most isometric combination was determined for the canine and human knees, and
trends in length patterns were also evaluated in both species relative to femoral
and tibial position. Statistical significance was determined by ANOVA.
Results
A combination joining a point caudal to the ACL origin (over-the-top) and anterior
on the tibial insertion was found to be the most isometric combination in both the
canine and human. The trends in change of length patterns across all reconstruction
combinations were similar in the dog and man. Isometry was improved as the reconstruction
was placed further posterior on the femur and anterior on the tibia. Conclusions:
The canine knee is an appropriate animal model for the study of isometry of the human
ACL and its reconstructions.
The length patterns of nine simulated Anterior Cruciate Ligament (ACL) reconstructions
were determined in the dog and man. In both species, the most isometric reconstruction
was one joining points corresponding to a position at the posterior edge of the intercondylar
roof of the femur (over-thetop) with a position anterior on the ACL insertion. For
the sake of clarity the term anterior cruciate ligament has been used, throughout,
for both species, instead of the cranial cruciate ligament (CCL) in the dog. Also
knee has been used in place of stifle for the dog.
Keywords
ACL - isometry - canine - human - biomechanics