Interface and biocompatibility of polyethylene terephthalate knee ligament prostheses. A histological and ultrastructural device retrieval analysis in failed synthetic implants used for surgical repair of anterior cruciate ligaments.

In a prospective clinical study of 54 patients with acute anterior cruciate ligament instability, 56 artificial ligaments made of polyethylene terephthalate (Trevira hochfest) were implanted to restore knee stability. The average follow-up of these artificial knee ligaments was 40.2 (12-79) months; five implants (10%) had to be explanted due to failure after an average of 17.8 (6-50) months. All explants were examined by histological and ultrastructural methods in a device retrieval analysis. With regard to short- and medium-term artificial ligament failure in the human knee joint, a non-isometric surgical implantation technique, inappropriate strain during rehabilitation and implant fatigue and wear were responsible for ligament failures.