Structure

The construction of the LARS ligament is the result of many years' detailed research – not only in finding a suitable biocompatible material which corresponds to the material properties of native structures, but also in identifying the best way to apply this material to produce the various ligaments available.

LARS are constructed from polyethylene terephthalate (PET), an industrial-strength polyester fibre which has been selected for its characteristics for ligament scaffold applications. There are over 500 different types of PETs, each with their own specific physical and mechanical characteristics. In contrast to previous generation synthetic ligaments, LARS are extensively treated to remove residual processing aids which were found to inhibit soft tissue in-growth, providing a more fibroblastic friendly environment (see graph below). The intra-articular portion of the LARS ligament consists of longitudinal fibres without transverse or crossing components.		LARS reflects a third generation ligament design

		First generation synthetics caused fretting.

		Second generation synthetics showed no improvement in tissue in-growth.

		Third generation synthetics with high porosity free fibres demonstrate excellent tissue in-growth.

Free fibres are oriented to the ligament they are intended to be used with, mimicking the normal anatomic fibres. This patented structure allows a high resistance to fatigue, especially in flexion, as well as providing a porosity favouring fibroblastic in-growth which then isolates the synthetic fibres.

In the extra-articular portion, the same parallel fibres are kept united by a process of warp knitting. This knitting process minimises secondary elongation (as opposed to braided or woven fibres).

graph

LARS cleaning process facilitates good tissue in-growth.

The material properties of ligaments designed for the various indications correspond with the material properties of their native counterparts in regards to tensile strength.

Each type of LARS ligament contains a specific number and length of fibres depending on the intended use, and varying 'leaders' to facilitate passage through the bony tunnels. Some ligaments contain free-fibres and some not, depending on their specific indication or the specific purpose or goal of the surgical intervention. Resistance to traction varies with the number of longitudinal fibres – approximately 1500N for 30 fibres, 2500N for 60 fibres, 3600N for 80 fibres and 4700N for 100 fibres.

Important: LARS is not available or cleared for distribution in all international markets. For more details, please contact your local subsidiary or distributor by visiting the Corin worldwide section of the Corin Group corporate website.