Abstract. Ligart project aimed to propose a new generation of artificial ligament which can be considered as “bioactive” and “biointegrable” destined to be used in anterior cruciate ligament (ACL) reconstruction surgery of patients with knee ACL rupture frequently related to contact and pivoting sports. Such bioactive ligament will allow preventing hostile host response due to the presence of a bioactive polymer grafted on its surface. The LARS prosthetic ligament made of poly (ethylene terephtalate) is chemically grafted by a “bioactive” and “biomimetic” polymer, which will allow masking the synthetic origin of the material and controlling collagen secretion, fibroblasts proliferation and inflammatory response. The bioactive ligament can be considered as “biointegrated”, i.e. integrated by the living system: it induces controlled fibroblast cell proliferation and colonization along the PET fibres of the joint part of the prosthetic ligament, ensure and/or steady appropriate mechanical behaviour of the ligament which can be compared to that of the biological ACL, decrease the inflammatory response and prevent acute synovites extensively described in the case of the first generation of synthetic ligament. Fifty-six sheep divided in two series devoted to the evaluation of (1) the biological response (histology, molecular biology, SEM) and (2) the biomechanical behaviour were implanted with bioactive polymer grafted or commercial ACL for 3 or 12 months. Results show that the grafting of PET ligament by the bioactive polymer sensitively improves the biological response at 3 and 12 months. Preclinical study in dog has started and experiments on human are scheduled in the next future.