CONTEXT

Ligament rupture and especially the rupture of the anterior cruciate ligaments (ACL) in the knee is a frequently occurring sports-related injury affecting hundreds of thousands of people worldwide each year. Due to their poor healing ability, torn ligaments most often need to be replaced by an autograft obtained from a tendon sample. While the clinical output is satisfactory, this autograft reconstruction still has several limitations including residual donor site morbidity, long recovery times and the requirement of the additional harvest operation. Numerous artificial ligaments have been designed in the last fifty years but most if not all have been abandoned due to high rates of failure, loosening or chronic inflammation.

Today, the progress in surgical techniques and the development of novel biomaterials open new routes to make a biocompatible artificial ligament able to replace damaged ligaments durably. This invention is the result of a collaborative project that explored how biocompatible and low-friction hydrogel materials can be processed to replace native ligament tissues. Such a prosthetic alternative to the currently used biological grafts would provide advantages for patients and surgeons and would be a significant advance in the field of ligament reconstruction.

TECHNICAL DESCRIPTION

The LIGAGEL invention describes a novel type of artificial ligament using the promising performance of a hydrogel already developed at the Georgia Institute of Technology laboratories. Previous formulations of this material have shown excellent properties of biocompatibility causing no inflammation as a cartilage replacement. By means of a thorough study of the processing conditions and using hydrogel fibers, the mechanical performances of this material have been modified to mimic those of the fibrous collagen structure forming native ligaments.

Optimizing these modifications with mechanical tests and simulations, an artificial ligament was designed that reproduces closely the complex behaviour of native ligaments and fulfils the geometrical requirements for ligament reconstruction.

BENEFITS

The LIGAGEL systems are novel ligament substitutes that combine in one same material the excellent biocompatibility and low wear properties of hydrogels with the high tensile performances of fibers. Versatility of hydrogel characteristics and fiber assembly provides a wide range of complex mechanical performances with non-linearities and anisotropies of interest for both compliant and stiff tissues such as menisci, ligaments and tendons.