João Luiz Vieira da Silva

Análise biomecânica da solidarização de tendões para reconstrução do ligamento cruzado anterior

OBJECTIVE:To evaluate the difference of the mechanical behavior of bended tied (sewed) and not tied hamstring tendons in order to evaluate if it has any effective function. METHODS: Twenty-four fresh bovine digital tendons had been used. Alginate to determine the area of the tendon transversal section was used. Ten bovine tendons had been bended and tied following the manufacturer orientation, ten others pairs had not been tied. Claws had been developed for the grafts fixation to the universal machine, for the setting simulation. The superior one was characterized to be bipartite and to have controlled passage for the pins and the inferior claw is characterized to have alternating teeth. RESULTS: The maximum load of the not tied samples of the test was 849,4 N ± 386,8 the area was 30,4 mm2 ± 7,7, and 29 ± 17 Mpa of tension. The tied ones had gotten maximum load of 871,8 N ± 484,9, area of 35 mm2 ± 5,8, and 24 ± 10 Mpa of tension. It did not have statistical difference between the two groups (p>0,05). CONCLUSION: The probability distribution showed that with 400 N the not tied tendons represents 83,8% of trustworthiness and the tied ones represents 78,5%.

Hamstring tendons insertion - an anatomical study

Objective To study the anatomy of the hamstring tendons insertion and anatomical relationships. Methods Ten cadaver knees with medial and anterior intact structures were selected. The dissection was performed from anteromedial access to exposure of the insertion of the flexor tendons (FT), tibial plateau (TP) and tibial tuberosity (TT). A needle of 40 × 12 and a caliper were used to measure the distance of the tibial plateau of the knee flexor tendons insertion at 15 mm from the medial border of the patellar tendon and tibial tuberosity to the insertion of the flexor tendons of the knee. The angle between tibial plateau and the insertion of the flexor tendons of the knee (A-TP-FT) was calculated using Image Pro Plus software. Results The mean distance TP-FT was 41 ± 4.6 mm. The distance between the TT-FT was 6.88 ± 1 mm. The (A-TP-FT) was 20.3 ± 4.9°. Conclusion In the anterior tibial flexor tendons are about 40 mm from the plateau with an average of 20°.

Estudo anatômico das duas bandas do ligamento cruzado anterior com o joelho em 90º de flexão

OBJECTIVE To anatomically evaluate the femoral origin and tibial insertion of the anteromedial and posterolateral bands of the anterior cruciate ligament. METHODS We studied eight cadaver knees as for the following: in the femur, distance from the center of the anteromedial band to the deep cartilage and the ceiling; also in the femur, distance from the center of the posterolateral band to the deep cartilage, to the inferior cartilage and to the superficial cartilage. In the tibia, we measured the distances between the anterior tibial bone edge to the anterior region of the anteromedial band, to the center of the anteromedial band and to the center of the posterolateral band. We also measured the distance between the center of the posterolateral band to the tibial posterolateral bone and the total length of the anteroposterior tibial insertion of the anterior cruciate ligament. RESULTS In the femur, the distance from the center of the anteromedial band to the deep cartilage was 6.3 ± 1.4 mm, and 11.2 ± 2 mm to the ceiling. Also in the femur, the distance from the center of the posterolateral band to the deep cartilage was 9 ± 4 mm, to the superficial cartilage 7.6 ± 1.8 mm, and to the inferior cartilage 4.2 ± 0.9 mm. In the tibia, the distance from the anterior tibial bone edge to the anterior region of the anteromedial band was 11.9 ± 2.8 mm, to the center of the anteromedial band 18.8 ± 2.6 mm, and to the center of the posterolateral band 26.5 ± 2.3 mm. The distance from the center of the posterolateral band to the tibial posterior bone edge was 19.6 ± 4 mm and the total length of the anteroposterior tibial insertion of the anterior cruciate ligament was 19.4 ± 1.8 mm. CONCLUSION The center of the tibial insertion of the anteromedial band is approximately 20mm distant from the anterior edge of the tibia, while the center of the posterolateral band is approximately 30 mm. The distance between the center of the origin of the anteromedial band to the deep cartilage is 6mm, and to the posterior lateral 10mm.

MACROSCOPIC ANALYSES OF THE EFFECTS OF HYALURONATES AND CORTICOSTEROIDS ON INDUCED OSTEOARTHRITIS IN RABBITS’ KNEES

Objective: To evaluate the effects of intra-articular injections of corticosteroids, native hyaluronic acid and branched-chain hyaluronic acid in experimentally-induced osteoarthrosis. Methods: 44 rabbits underwent anterior cruciate ligament resection and were then divided into four groups of eleven. Group 1: one intra-articular injection of saline solution per week, for three weeks; Group 2: three injections (one per week) of native hyaluronic acid; Group 3: three injections (one per week) of branched-chain hyaluronic acid; Group 4: two injections of betamethasone with an interval of three weeks. The cartilage of the tibial plateaus was evaluated macroscopically twelve weeks after surgery. Changes to the joint surface were graded as follows: Grade 0: smooth joint surface without relief changes; Grade 1: rough surface without any depressions; Grade 2: similar to grade 1, but with depressions on the joint surface; and Grade 3: subchondral bone exposure. The statistical analysis consisted of the use of Students t test, chi-square test and analysis of variance (ANOVA). The significance level used was 5%. Results: A statistical difference was found between the control group and the three study groups 2, 3, 4 in relation to the development and severity of arthrosis. However, there was no difference between the groups regarding the drugs studied. Conclusion: A similar degree of attenuation of the osteoarthrosis process in the rabbits’ knees was found with the use of intra-articular injections of low-molecular-weight and high-molecular-weight glycosaminoglycans, and the corticosteroid betamethasone, compared with placebo.

É possível prever o comprimento de tendões flexores do joelho por antropometria

OBJECTIVE To compare the anthropometric data and the sportive way of life with the hamstring tendons dimensions, prospectively, in order to create a rule to predetermine its dimensions. METHODS General and anthropometric data were collected from 30 patients that were submitted to anterior cruciate ligament reconstruction. These data were correlated to the diameter and length of the hamstring tendons. The data collected were: height, weight, age, knee lesion side, body mass, sportive training level, femoral length, tibia length, thigh circumference, and knee circumference. The correlation was made by Pearson coefficient. RESULTS Statistic significant correlation occurred only with height and tibia length versus the gracilis and semitendinous tendon length. Using linear regression the relations found could be expressed with the following formulas: semitendinous length = -2.276 + 0.177 x height; semitendinous length = 13.048 + 0.46 x tibia height; gracilis length = -9.413 + 0.207 x height; gracilis length = 7.036 + 0.583 x tibia height. CONCLUSION It is possible to predetermine hamstring tendons length through linear regression formulas before surgical intervention.

BIOMECHANICAL STUDY OF TRANSCORTICAL OR TRANSTRABECULAR BONE FIXATION OF PATELLAR TENDON GRAFT WITH BIOABSORBABLE PINS IN ACL RECONSTRUCTION IN SHEEP

Objective: To determine the initial resistance of fixation using the Rigid Fix® system, and compare it with traditional fixation methods using metal interference screws; and to evaluate the resistance of the fixation with the rigid fix system when the rotational position of the bone block is altered in the interior of the femoral tunnel. Methods: forty ovine knee specimens (stifle joints) were submitted to anterior cruciate ligament reconstruction (ACL) using a bone-tendon-bone graft. In twenty specimens, the Rigid Fix method was used; this group was subdivided into two groups: ten knees the pins transfixed only the spongious area of the bone block, and ten for fixation passing through the layer of cortical bone. In the twenty remaining specimens, the graft was fixed with 9mm metal interference screws. Results: comparison of the RIGIDFIX® method with the metal interference screw fixation method did not show any statistically significant differences in terms of maximum load and rigidity; also, there were no statistically significant differences when the rotational position of the bone block was altered inside the femoral tunnel. For these evaluations, a level of significance of p < 0.017 was considered. Conclusion: fixation of the bone-tendon-bone graft with 2 bioabsorbable pines, regardless of the rotational position inside the femoral tunnel, gave a comparable fixation in terms of initial resistance to the metal interference screw, in this experimental model.

Estudo biomecânico da fixação transcortical ou transesponjosa do enxerto de tendão patelar com pinos bioabsorvíveis na reconstrução do LCA em ovinos

OBJECTIVE: to determine the initial resistance of fixation using the Rigid Fix® system, and compare it with traditional fixation methods using metal interference screws; and to evaluate the resistance of the fixation with the rigid fix system when the rotational position of the bone block is altered in the interior of the femoral tunnel. METHODS: forty ovine knee specimens (stifle joints) were submitted to anterior cruciate ligament reconstruction (ACL) using a bone-tendon-bone graft. In twenty specimens, the RigidFix® method was used; this group was subdivided into two groups: ten knees used for fixation with trabecular bone screw, and ten for fixation passing through the layer of cortical bone. In the twenty remaining specimens, the graft was fixed with 9mm metal interference screws. RESULTS: comparison of the Rigidfix® method with the metal interference screw fixation method did not show any statistically significant differences in terms of maximum load and rigidity; also, there were no statistically significant differences when the rotational position of the bone block was altered inside the femoral tunnel. For these evaluations, a level of significance of p < 0.017 was considered. CONCLUSION: fixation of the bone-tendon-bone graft with 2 bioabsorbable pines, regardless of the rotational position inside the femoral tunnel, gave a comparable fixation in terms of initial resistance to the metal interference screw, in this experimental model.