Mauro Batista Albano

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%.

Análise fotocolorimétrica computadorizada dos efeitos da betametasona intra-articular sobre a concentração de proteoglicanos da matriz cartilaginosa de joelhos leporinos: influência do número de injeções intra-articulares

OBJECTIVE To study the effects of repeated injections of betamethasone on proteoglycan concentration in the articular cartilage of normal knees of Californian rabbits of both sexes. METHODS Eighty animals were randomly divided into eight groups of ten animals each. Three control groups (saline solution injected or not) and five study groups - therapeutical doses, repeated or not, of betamethasone injected into the right knee of each animal at weekly intervals. After eight days from the last injection, sections of articular cartilage from tibial plateaus collected from weight-bearing surfaces were stained with hematoxylin and eosin for light microscopy analysis and with safranin O for the proteoglycan content assay. The staining intensity of safranin O was quantified by histomorphometry using an Olympus BX 50 microscope and a microcomputer with the Image Pro-plus 4.5O software. RESULTS Animals receiving one, two and four betamethasone injections showed no differences when compared to normal controls. Animals receiving six and eight injections had a significant decrease in safranin O staining intensity (p < 0.05) as compared to the control groups and the other study groups. CONCLUSION A decrease in the concentration of articular cartilage proteoglycans dependent on repeated betamethasone injection was effectively demonstrated.

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.

Effect of hyaluronic acids as chondroprotective in experimental model of osteoarthrosis

Objective to analyze the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits. Methods forty‐four male California rabbits were divided randomly into three groups and underwent resection of the anterior cruciate ligament in his right knee. After three weeks of the surgical procedure began three weekly intra‐articular injections of hyaluronic acid native (Polireumin®)‐PR, hyaluronic acid branched chain (Synvisc®)‐S and 0.9% saline‐P. All animals were sacrificed after twelve weeks of surgery and tibial plateau infiltrated the knees were dissected. Histological cartilage of the support areas of the tibial plateaus were stained with Alcian Blue pH 1.0, Alcian Blue pH = 2.5 and toluidine blue for research on the amount of proteoglycans. The intensity of staining was quantified on a Zeiss microscope apparatus Imager Z2 MetaSystems and analyzed by software MetaferMsearch. Results the effect of chondroprotetor hyaluronic acids used in the study was confirmed when compared to the control group, but the comparison made between them, there was no statistically significant difference regarding chondroprotetion. Conclusion the hyaluronic acids tested had chondroprotective effect, with no statistical difference with regard to the different molecular weights.

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.

Intra-articular viscosupplementation of hyaluronic acids in an experimental osteoarthritis model

Objective To analyze, from the immunohistochemical perspective, the effects of hyaluronic acid of different molecular weights in an experimental model of osteoarthritis in rabbits. Methods Forty-four male California rabbits were randomly assigned to three different groups (PR, S, and P) and submitted to the resection of the anterior cruciate ligament of the right knee. Three weeks after the surgical procedure, three intra-articular weekly injections were carried out with low-molecular-weight native hyaluronic acid (Hyalgan®) to PR group, high molecular weight branched chain hyaluronic acid (Synvisc®) to group S, and saline solution 0.9% to group P. All animals were sacrificed 12 weeks after the surgical procedure, and the tibial plateaus of the infiltrated knees were then dissected. Histological sections of cartilage from the tibial plateau support areas were stained with immunohistochemical markers in order to investigate the amount of metalloproteases (MMPs 3 and 13) and their inhibitors (TIMPs 1 and 3). The staining intensity was quantified on a Zeiss Imager.Z2 Metasystems microscope and analyzed by Metafer4 Msearch software. Results The chondroprotective effect of the hyaluronic acids used in the study was demonstrated when compared to the control group. However, the comparison between them presented no significant statistical difference regarding chondroprotection. Conclusion The injection of saline solution demonstrated signs of OA development, while adding native hyaluronic acid of low molecular weight (Hyalgan®) and hyaluronic acid of high molecular weight (Synvisc®) protected the articular cartilage in this model of OA.

Knee ligament injuries: biomechanics comparative study of two suturetechnique in tendon - analysis "in vitro" tendon of bovine

Objective To evaluate and compare the biomechanical behavior of two different suture configurations:“X”and“Loop”in the preparation of tendons for knee ligament reconstruction. Methods We used common digital extensor tendons of bovine that can replace the human flexor tendons in experimental studies of traction. In the first group, point “X” suture with Ethibond ® No. 5 began in the distal graft points transfixing, with spacing of 7.5 mm points to reach 03 cm distal to the beginning of the suture, returning suture in the same manner, transfixing the tendon in open spaces across the suture configuration “X”. The second group, the point “Loop” was prepared with the same type Ethibond ® No. 5 of the needle wire was removed for use only of the wire was mounted in a twofold manner in a single piece forming a needle loop. Started the suture 3 cm from the end of the graft through loops and transfixing points throughout the tendon substance, with spacing between dots of 7.5 mm. Result The Maximum Force of Rupture suture in “Loop” was 444.45 N and the suture in “X” was 407.59 N with statistical significance (p = 0.030). The average Tension obtained at the suture in “Loop” was 27.67 MPa and at the suture in “X” was 25.73 MPa with a statistically significant difference (p = 0.036). The stiffness showed no statistical differences (p = 0.350) at 11.804 N / mm at the point where “Loop” and 11.570 N / mm at the suture “X”. Conclusion The suture in “Loop” had a higher biomechanical behavior to the suture “X”, considering the Maximum Force and Tension.

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.