ABSTRACT
In the present study we describe the synthesis, wet spinning, mechanical testing, and degradation of poly(urethane urea)s (PUURs) intended for clinical use in anterior cruciate ligament (ACL) reconstruction. The effects of soft segment chemical composition and molar mass and the kind of diamine chain extender on the material properties were investigated. It was found that the fibers made of PUUR with polycaprolactone diol (PCL530) as soft segment and MDI/1,3-DAP as hard segment (PCL530-3) have high tensile strength and high modulus and when degraded keep their tensile strength for the time demanded for the application. In conclusion, from a chemical and mechanical point of view PUUR fibers of PCL530-3, ARTELON, are suitable for designing a degradable ACL device.
Subject(s)
Ligaments , Polyurethanes/chemical synthesis , Prostheses and Implants , Biocompatible Materials/chemical synthesis , Biocompatible Materials/chemistry , Biocompatible Materials/therapeutic use , Biodegradation, Environmental , Humans , Materials Testing , Polyurethanes/chemistry , Polyurethanes/therapeutic use , Porosity , Temperature , Tensile StrengthABSTRACT
The present report describes the mechanical tests, in vitro and in vivo studies of a poly(urethane urea) (PUUR) intended for clinical use in anterior cruciate ligament (ACL) reconstruction. In the mechanical tests, no evidence of severe fatigue was observed after repeated cyclic loading. Testings for mutagenicity and delayed contact hypersensitivity were found negative. Three in vivo studies were performed in rabbits and minipigs. Altogether 35 rabbits were operated upon in (1) an intraarticular implantation study, performed to evaluate the soft tissue response to woven bands and fiber bundles of PUUR and (2) a rabbit ACL study, examining the function of the PUUR ACL replacement and the tissue response to the material. In a third study, PUUR ACL replacement in minipigs was evaluated. Taken together, ingrowth of connective tissue in close contact with the PUUR fibers was detected both in rabbits and minipigs. The first clear histological signs of degradation of the polymer was detected after 24 months. In conclusion, the evaluated mechanical properties of the PUUR band correspond to those of the mature, human ACL. Furthermore, both from a histological and functional point of view, the PUUR woven band show interesting properties for future clinical ACL reconstructions.
