The copolymer poly (L-co-D,L lactic acid), PLDLA, has gained prominence in the field of temporary prostheses due to the fact that their time of degradation is quite compatible with the requirement in the case of osseous fracture. In this work the in vivo degradation of devices from copolymer, as a system of plates and screws, used in fixation of the tibia of rabbits was studied. The devices were implanted in 15 adult rabbits, albinos, New Zealand race, and they were used as control devices of alloys of titanium (Ti-6Al-4V/ V grade). The use of copolymers, synthesized in the laboratory, was tested in the repair of fracture in rabbits'tibias, being assessed in the following times: 2 weeks, 2 months and 3 months. Morphological analysis of tissue surrounding the plate and screw system, for 2 weeks of implantation, showed the presence of osteoblasts, indicating a pre bone formation. After 2 months there was new bone formation in the region in contact with the polymer. This bone growth occurred simultaneously with the process of PLDLA degradation, invading the region where there was polymer and after 3 months there was an intense degradation of the copolymer and hence greater tissue invasion compared to 2 months which characterized bone formation in a region where the polymer degraded. The in vivo degradation study of the devices for PLDLA by means of histological evaluations during the period of consolidation of the fracture showed the efficiency of plate and screw system, and it was possible to check formation of bone tissue at the implantation site, without the presence of inflammatory reaction.14310701075Menezes, A.C.M., (2007) Síntese E Caracterização De Dispositivos De Poli (l-co-d,l Ácido Láctico). Estudo Da Degradação In Vitro E In Vivo, , Tese de D.Sc., UNICAMP, Campinas, SP, BrasilAlexander, J.T., Branch Jr., C.L., Subach, B.R., Applications of a resorbable interbody spacer via a posterior lumbar interbody fusion technique (2002) Orthopedics, 25 (SUPPL. 10), pp. S1185-S1189Landes, C.A., Kriener, S., Menzer, M., Kovacs, A.F., Resorbable plate osteosynthesis of dislocated or pathological mandibular fractures: A prospective clinical trial of two amorphous L-/DL-lactide copolymer 2mm miniplate system (2003) Plastic Reconstructive Surgery, 111 (2), pp. 601-10Punja, K.D., Morrison, V.G.K., Reconstruction of complex orbitocranial deformities using bioresorbable mesh, Sterelized Orbiatl Models and In situ Contouring (2006) Ophthalmic Plastic and Reconstructive Surgery, 22 (1), pp. 20-24Viinikainen, A.K., Gransson, H., Huovinen, K., Kelloma, M., Tormala, P., Rokkanen, P., Bioabsorbable poly-L/D-lactide (PLDLA) 96/4 triple-stranded bound suture in the modified Kessler repair: An ex vivo static and cyclic tensile testing study in a porcine extensor tendon model (2009) Journal of Materials Science: Materials In Medicine, 20, pp. 1963-1969Cohen, S.R., Holmes, R.E., Amis, P., Fitchner, H., Shusterman, E.M., Technical strategies tacks: A new technique for craniofacial fixation (2001) J Craniofac Surg, 12, pp. 596-602Motta, A.C., Duek, E.A.R., Estudo inicial da degradação "in vitro" de poli(L-co-DL ácido lático) sintetizado em laboratório (2008) Revista Matéria, 13 (3), pp. 429-438van der Elst, M., Kuiper, I., Klein, C.P.A.T., Patka, P., The burst phenomenon, an animal model simulating the long-term tissue response on PLLA interlocking nails (1996) Journal of Biomedical Materials Research, 30, pp. 139-143Pennings, A.J., Rozema, F.R., Bos, R.R.M., Schmitz, J.P., Cytotoxicity of poly(96L/4D lactide): The influence of degradation and sterilization (2000) Biomaterials, 21, pp. 2433-2442Chandra, R., Rustgni, R., Biodegradable Polymers (1998) Progress. Polymer Science, p. 23