Estudo biomecânico comparativo entre técnicas cirúrgicas para o tratamento da ruptura do ligamento cruzado cranial em cães

Abstract

This study aimed to compare the craniocaudal and rotational stability of femorotibiopatelar joint (FTP) during weight bearing, as well as measure its flexion and extension goniometry after the use of intra-articular, extra-articular and tibial plateau leveling osteotomy (TPLO) techniques in limbs of dogs with cranial cruciate ligament (CrCL) rupture. 30 hind limbs of dogs were used and divided into three groups, according to the stabilization technique employed. The specimens were prepared and mounted in an apparatus for carrying out the tests with application of axial load of 40% of the body weight of the animal. Analyzes were performed prior to rupture of the CrCL, after rupture of the CrCL and after surgical stabilization. The craniocaudal stability was evaluated by photographic images taken with a high resolution camera in the sagittal plane and rotational stability for those performed in the dorsal plane. The pictures were taken in triplicates and analyzed using image processing software. The goniometry was measured at all three stages with a transparent goniometer. Parametric results were analyzed using ANOVA and Fishers test, and nonparametric results using Friedmans and Kruskal-Wallis tests. Differences were considered significant at p<0.004. There was an increase in the angle of flexion of the FTP joint in the intra-articular group (87.17° ± 25.33), whereas the TPLO group caused an increase in extension angle (173.44° ± 5.88). The stabilization of craniocaudal displacement of the tibia was similar in the three groups. The craniocaudal instability was not completely eliminated in any of the groups. The intra-articular (6.10° ± 12.81) and extra-articular (3.70 ° ± 1.55) techniques reduced the internal rotation of the tibia during stance, while the TPLO did not eliminate this instability (-7.67 ± 7.27º). The cranial displacement of the tibia following rupture of the CrCL did not correlate with the angle of the tibial plateau. It was concluded that the intra-articular and TPLO techniques interfere with the natural movement of the FTP joint increasing angles of flexion and hyper-extension, respectively, while the extra-articular technique does not alter these parameters. The three evaluated techniques are equally effective in limiting the cranial tibial displacement caused by the CrCL rupture, but none of the techniques completely eliminates this abnormal movement, maintaining similar residual instabilities. TPLO does not stabilize excessive internal rotation of the tibia following CrCL rupture, while intra and extra-articular techniques reduce this movement. The magnitude of the cranial tibial displacement during weight bearing in limbs with CrCL rupture is not influenced by the angle of the tibial plateau.