BIOCOMPATIBILITY AND MECHANICAL PROPERTY OF LARS ARTIFICIAL LIGAMENT WITH TISSUE INGROWTH

Tissue ingrowth into the implanted artificial ligaments is to be expected after reconstructive procedures and several groups have reported soft tissue ingrowth of the implanted LARS (Ligament Augmentation and Reconstruction System, Dijon, France) artificial ligament. Up to now the influence of the tissue ingrowth on the mechanical properties of the artificial ligament is uncertain. The purpose of this research was to study the mechanical property after tissue ingrowth on LARS artificial ligament. Five LARS ligaments were implanted subcutaneously in the abdomen of five pigs. After six months of implantation, four successful implants were explanted and tested. The results showed that fibroblasts and collagen fibers had grown into the unknotted middle part of the LARS. However, 12.2 +/- 2.2% of fibres were surrounded by foreign body giant cells. Tensile tests showed that the explanted LARS possessed similar elastic characteristics as native ligaments. The tensile strength of the explanted LARS decreased by 23.53 +/- 18.04% (p < 0.001) and the elongation of the middle part of the explanted LARS increased by 69.84 +/- 38.38% (p < 0.002) in comparison with unimplanted control ligaments. Since there were not apparent surface cracking on the LARS fibers, it was inferred that activities of foreign-body giant cells might have weakened the strength and adversely affected the mechanical properties of the fibers of the LARS.