Helical 6-Strand Cruciate Tenorrhaphy: Description of a New Technique and Biomechanical Comparative Analysis With 2 Standard Techniques.

Background: Multiple flexor tendon repair techniques have been developed over the last years. Despite all this, there is no standard technique that has proven to be superior to others, leading to great variability in the use of techniques in surgical practice. We describe a novel tendon repair technique and compare its biomechanical characteristics with 2 conventional techniques. Methods: Comparative experimental biomechanical study in ex vivo animal models. In all, 66 deep flexor tendons of the pig's front legs were taken and it's repair was performed by 1 of 3 techniques (helical 6-strand cruciate tendon repair, Adelaide tendon repair, or modified Kessler). These repairs were subjected to biomechanical study, measuring, and registering the ultimate tensile strength, load to 2-mm gap force, and stiffness. Results: The helical 6-strand cruciate tenorrhaphy compared with the Adelaide and modified Kessler techniques carries statistically significant greater ultimate tensile strength before failure (65.5, 46, and 36 N, respectively, P < .001). It also required a greater load to 2-mm gap force and is less stiff, allowing greater strain before failure. This technique does not generate significant changes in the dimensions of the tendons compared to the others, and there was no significant difference in the strength of repair between surgeons. Conclusions: The helical 6-strand cruciate tenorrhaphy is a novel technique, useful for the repair of flexor tendons in the hand that holds up the necessary forces to initiate early mobilization in the postoperative period and has better biomechanical properties than 2 standard techniques.

Efecto del tratamiento térmico y de fibras de polietileno en la resistencia a la flexión de resinas compuestas / Effect of heat treatment and polyethylene fiber in flexural strength of dental composites

Evaluar la influencia de la polimerización complementaria y de la adición de fibras de polietileno en la resistencia a la flexión de resinas compuestas. Se confeccionaron 50 cuerpos de prueba con la ayuda de una matriz metálica articulada (ISO 4049). Las muestras se dividieron (n=10) en los siguientes grupos: G1 (grupo control) resina compuesta indirecta; G2 resina compuesta directa; G3 resina compuesta directa + tratamiento térmico; G4 resina compuesta directa + fibra de polietileno; G5 resina compuesta directa + fibra de polietileno + tratamiento térmico. Para evaluar la resistencia a la flexión se aplicó el test de tres puntos (célula de carga 9800N; velocidad 1,0 mm/min). Se aplicó el análisis de varianza (ANOVA) para determinar las diferencias entre los grupos y el test de Dunnett para la comparación con el grupo control (p<0,05). La medida de tensión para el grupo control G1 fue la menor encontrada (100,49 MPa); G2 = 108,33 MPa; G3 = 124,29 MPa; G4 = 106,04 MPa y G5 = 124,08 MPa. El método de polimerización complementada con tratamiento térmico promovió un aumento significativo de la resistencia a la flexión (p = 0,032) de las resinas directas. La utilización de la fibra no mejoró el comportamiento de la resina directa (p = 0,854).

To evaluate the influence of polymerization and the addition of supplementary polyethylene fiber on the flexural strength of composites. 50 bars (25x2x2mm) were prepared with a stainless steel mold (ISO 4049). The samples were divided (n = 10) in G1 (control group) indirect resin composite; G2 direct composite; G3 direct composite + heat treatment; G4 direct composite + polyethylene fiber; G5 direct composite + polyethylene fiber + heat treatment. For flexural test was applied to three points (9800N load cell, speed 1.0 mm/min). The analysis of variance (ANOVA) was applied to determine differences between groups and Dunnett's test for the comparison with the control group (p <0.05). The strain average for the control group G1 was the lowest found (100.49 MPa); G2 = 108.33 MPa; G3 = 124.29 MPa; G4 = 106.04 MPa; and G5 = 124.08MPa. The method of polymerization in autoclave additional significant increases in flexural strength (p = 0.032) of direct resins. But the use of fiber did not improve the performance of direct resin (p = 0.854).