Polyethylene Fibers as Substitute for Anterior Cruciate Knee Ligament in Goats: A Histological Study

Abstract

The treatment of an unstable knee resulting from anterior cruciate ligament (ACL) tear is still controversial. Many different procedures for reconstruction have been described in the quest for a solution to this problem. All surgical methods aim at reproducing the properties of the natural ligament as accurately and quickly as possible. The search for the optimal ACL replacement has led researchers in various directions, but the two major groups are those preferring allogenic substitution and those favoring the use of synthetic material. It is well known that autogenic grafts undergo necrosis postoperatively, and that several months are required for revascularization [3, 4]. Allogenic materials are nonviable to start with; moreover they stretch out with time, resulting in loss of stability. A synthetic substitute is expected to take over the mechanical load of the damaged ligament, and the period of immobilization following surgery is remarkably shortened or eliminated. There are a few materials with the mechanical strength to withstand the normal loading of the ACL and the millions of cycles of cyclic loading to which the ACL is subjected. Carbon was expected to be an inducting and conducting material that would transform from a synthetic prosthesis into a biological replacement with natural collagen, but it quickly failed due to its brittleness [7]. Attempts to coat it with gelatin or polylactic acid did not improve its quality, the main drawback being its inability to withstand bending and shear stresses that lead to breakage.