The Experience of ACL Reconstruction with Synthetics Ligament: Where are we now?

Abstract

The dispute on artificial ligaments used for anterior cruciate ligament (ACL) reconstruction has been a long time issue. Admittedly, due to designing defects, materials deficient without creeping, viscoelasticity and biocompatibility, and incorrect surgical technique, early application of synthetic ligament in ACL reconstruction did not yield good outcomes. For a long time, a poor outcome occupied our consensus. Whilst the poignant lessons didn’t drive people to thoroughly figure out underlying reasons but amplified the fear of synthetics ligament in the ACL reconstruction. Recent 15 years, a new generation synthetic ligament, Ligament Advanced Reinforcement System (LARS) developed for ACL/PCL reconstruction has been widely used in China. There are at least 147 papers on LARS published in Chinese and over 47 SCI papers published in English. Consistently, a positive outcome has been concluded in most reports with an early return to sports and lower complication or failure rate. Cumulative failure rate from short- and mid-term follow-ups was only 2.6% according to Batty et al., which has been commended as “surprisingly impressive” by James H. Lubowitz of journal Arthroscopy. In China, LARS ligaments have been approved by CFDA since 2004 and been used for ACL reconstruction over 30,000 cases. Recently a national multi-centers clinical investigation has been done in long-term failure analysis of the ACLR with LARS, which has involved 20 Chinese clinical centers and 1146 cases with mean follow-up time of 87 months（7 years）, organized by the Chinese Artificial Ligament Study Group (CALSG), with an acceptable outcome in failure rate of 4.5% and complication rate of 4.1%. The following factors were concluded as main failure reasons, 1）incorrect surgical technique in a non-isometric ACL reconstruction, 2）lack of the graft biocompatibility and rigid screw interface fixation, 3) non-suitable indicated patients’ selection and rehabilitation program. Compared with reported long-term failure rate in auto（10%）or in allografts（24%）, the outcome of Synthetic ligament was more superior and acceptable results. Moreover, the functional evaluation and return to sports of the patients were also high satisfying, despite some complication, such as screw loose, remnant stimulation but very rear synovitis. Non-isometric tunnel position was the main failure reason which caused by surgeons tech. An ISOMETRIC surgical technique should be stressed especially in ACL reconstruction using synthetic, focused on surgeon education, instead of simply blaming the artificial graft. Based on the systemic review and our study, a modification of synthetic graft has been developed successfully in experiment, graft fixation, synthetics materials modified with Polyethylene Terephthalate (PET) which has facilitated the biocompatibility. Our clinical investigation has also focused on a near-isometric ACL reconstruction, which would decrease the graft tunnel motion and facilitate artificial graft successful. Non-isometric input will predispose the grafts easy failure because of over tension on the graft while joint moving. Carefully selected patients, proper surgical technique, and standard rehabilitation program will ensure artificial ligament successfully. We will keep devoting to innovate artificial ligaments, including tissue engineering, bio-mimics design, advanced fixation, hybrid graft designing and more precise Isometric surgical technique. Never forgetting our beginning mind, the artificial ligaments will open a new epoch in the future of ACL reconstruction.