Comparative kinetic and kinematic evaluation of TPLO and TPLO combined with extra-articular lateral augmentation: A biomechanical study.

Abstract

OBJECTIVES: To investigate stifle kinematics and kinetics following TPLO and TPLO combined with an extra-articular lateral augmentation (TPLO-IB) during the tibial compression test (TCT) and the tibial pivot compression test (TPT), applied with an external (eTPT) and an internal moment (iTPT). STUDY DESIGN: Experimental ex vivo study. SAMPLE POPULATION: Ten cadaveric hindlimbs of dogs weighing 23-40&#x2009;kg. METHODS: 3D-kinematic and kinetic data were collected while performing TCT, eTPT, and iTPT and compared under the conditions (1) normal, (2) CCL deficient, (3) TPLO, and (4) TPLO-IB. Two-way repeated-measures ANOVA was used to examine the effect of test and treatment on kinetic and kinematic data. RESULTS: Mean&#x2009;&#xb1;&#x2009;SD preoperative TPA was 24.7&#xb0;&#x2009;&#xb1;&#x2009;1.7&#xb0;, postoperative TPA was 5.9&#xb0;&#x2009;&#xb1;&#x2009;0.7&#xb0;. During TCT, there was no difference in cranial tibial translation between the intact stifle and after TPLO (p&#x2009;=&#x2009;.17). In contrast, cranial tibial translation was six times larger in TPLO compared to intact when performing eTPT and iTPT (p&#x2009;<&#x2009;.001). Cranial tibial translation with TCT, eTPT and iTPT was not different between intact stifle and TPLO-IB. Intraclass correlation coefficient for eTPT and iTPT after TPLO and TPLO-IB was excellent being 0.93 (0.70-0.99) and 0.91 (0.73-0.99), respectively. CONCLUSION: Whereas TCT is negative after TPLO, instability persists when a rotational moment is combined using eTPT and iTPT. TPLO-IB neutralizes craniocaudal and rotational instability when performing TCT, eTPT, and iTPT.