Objective: To evaluate the effect of two tibial attachment sites for lateral suture stabilization (LSS) on the kinematics of the cranial cruciate ligament-deficient (CrCL-D) canine stifle during early, middle and late stance.<br />Study design: In vitro biomechanical study: 32 hind limbs from 16 canine cadavers.<br />Methods: Limbs were mounted in a testing jig and an electromagnetic tracking system was used to determine 3-D stifle kinematics under 33% body weight load during early, middle and late stance in the following sequence: CrCL intact, CrCL-D and LSS with the distal anchor through the tibial tuberosity (LSSTT) or through the cranial eminence of the extensor groove (LSSEG). The proximal anchor point was the lateral femoro-fabellar ligament.<br />Results: Transection of the CrCL resulted in significant changes in stifle kinematics during early, middle and late stance. Post-LSS stifle kinematics were more comparable to normal than post-transection kinematics for both techniques. Both LSS techniques restored stifle kinematics in CrCL-D stifles to varying amounts but neither technique successfully restored normal 3-D stifle kinematics. LSSEG improved kinematics of the CrCL-D stifle in the medial-lateral direction and axial rotation but performed poorly in restoring stifle kinematics in the cranial-caudal plane as compared to LSSTT.<br />Clinical significance: LSSTT and LSSEG techniques failed to completely restore normal stifle kinematics in CrCL-D stifles in vitro. / Master of Science

Objective: To evaluate the relative position of the femur and tibia in cranial cruciate ligament (CCL) intact stifles, CCL deficient stifles, and stifles following a novel extracapsular procedure (lateral extracapsular suture system or LESSa) under load at specific joint angles. Study Design: In vitro biomechanical study. Methods: Twenty pelvic limbs from 11 dogs were used to evaluate the relative position of the femur and tibia between 3 stifle conditions (CCL intact, CCL deficient, and LESSa treated) at a load of 30 % and stifle angles of 125", 135", and 145" using electromagnetic tracking sensors. Results: Cranial cruciate ligament deficient stifles had significantly greater (p <0.0001) cranial displacement and internal rotation of the tibia relative to the femur than CCL intact stifles or LESSa treated stifles at all stifle angles. Cranial displacement of the tibia relative to the femur for CCL intact and LESSa treated were not significantly different from one another at stifle angles of 125", but were significantly different at stifle angles of 135" (p = 0.0182) and 145" (p = 0.0012). There was no significant difference in internal rotation of the tibia relative to the femur between CCL intact and LESSa treated stifles at any of the stifle angles. Conclusion: LESSa effectively decreases cranial tibial displacement and eliminates internal rotation of the tibia relative / Master of Science

Objective: To determine the ability of the Tibial Plateau Leveling Osteotomy (TPLO) to restore normal joint kinematics in a cranial cruciate ligament (CrCL)-deficient stifle through a loaded range of motion. Methods: Paired pelvic limbs from 12 dogs were compared in an in vitro biomechanical study. Each limb was placed in a custom designed jig at 120° of stifle extension under an axial load of 20% body weight. Electromagnetic motion tracking sensors were placed on the distal femur and proximal tibia. A force was applied at approximately 10 N/sec to mimic the action of the quadriceps muscle. Force application allowed the limb to move from 120° to maximal extension. Positional data was acquired at 60 points/second. Each limb was tested under normal, CrCL-deficient, and TPLO-treated conditions. Results: The TPLO failed to normalize CTT within the CrCL-deficient stifle; however, values trended towards intact values throughout the range of motion. No significant differences were noted in internal rotation in any of the three conditions from 120° – 137°. Hyperextension values did not differ significantly between conditions. Conclusion: Data from this biomechanical model suggests that the TPLO fails to neutralize CTT throughout a loaded range of motion. Internal rotation and hyperextension values were not found to differ significantly between intact, CrCL-deficient and TPLO repaired stifles. The effectiveness of the TPLO in restoring normal biomechanics is more significant at greater angles of flexion. / Master of Science