Clinical Outcome of Lateral Extraarticular Augmentation Procedure for Anterior Cruciate Ligament Reconstruction: Systematic Review of Recent 5-year Studies

Objectives: Anterolateral rotational instability contributes to the persistent significant failure rate after anterior cruciate ligament reconstruction (ACLR) and suggests an inability of the intra-articular graft to normalize knee kinematics. Therefore, there has been a renewed interest in lateral-based soft tissue reconstructive techniques as augmentation of ACLR. Previous reviews regarding this topic have been published, yet the emergence of new findings should be considered to decide the best treatment. The aim of this study is to systematically review evidence of lateral extraarticular augmentation procedure (LEAP) for ACLR in the past 5 years. Methods: Literature research was performed using the PubMed/MEDLINE database for English-language studies pertaining anterolateral or lateral extraarticular procedure for ACLR. This systematic review was conducted based on PRISMA guideline. Inclusion criteria were patients who underwent ACL reconstruction with a combination of intraarticular and extraarticular procedure as augmentation. We excluded studies using isolated extraarticular procedure and studies on cadavers. The primary outcome assessed was subjective and objective clinical outcome. Results: After assessing full text and applying inclusion and exclusion criteria, six articles from 2015-2018 were found to be eligible, with 360 patients undergoing ACLR and LEAP. Level of evidence for the articles were II (n=2), III (n=2), and IV (n=2). The basic data of the studies were as follows: patients age was 16-48 years old; weight was 48-95 kg. Time from injury to surgery is more than 3 months, with one study included only patients with more than 12 months of injury. The procedure is in general indicated for strenuous sporting activities, while excluding collateral ligaments injury. Grafts were taken from gracilis tendon with only 1 study used semitendinosus. After a follow-up ranging from 2-24 years, both subjective (IKDC, Lysholm, Tegner, KOOS, and VAS) and objective (pivot shift test, KT-1000 arthrometer, and laxity tests) functional outcome was found to be satisfying. Two studies found no statistically significant difference with isolated ACLR, while one study favoured the use of LEAP. Most studies agreed that less ACL graft failure was found with LEAP. The complication was minimal, consisting of superficial wound infection. Discussion: Compared to acute ACL injuries, chronic injuries have higher anterolateral laxity. This instability is due to an anterior asymmetrical translation of the lateral tibial plateau. When there is injury or insufficiency of anterolateral structures, either by acute injury that does not heal properly or by the loosening resulting from an untreated ACL injury, it is more complicated to restore normal knee kinematics. It was found that by adding lateral extra-articular procedure to ACL reconstruction, internal rotation of the tibia at 30° of knee flexion can be reduced more significantly compared with either single-bundle or anatomic double-bundle reconstruction. However, three studies with less than 12 months period from injury to surgery concluded that LEAP did not give statistically significant difference in terms of functional outcome. Only one comparison study with more than 12 months of injury favored LEAP, indicating that more chronic injuries might benefit more from this procedure. Despite the differing results of functional outcome among studies, there is a common understanding that LEAP gives significantly better results in terms of pivot-shift test. Two previous systematic reviews agreed that combined procedure of ACLR and LEAP resulted in improvement of pivot-shift, without any statistically significant difference in terms of subjective outcome measures with ACLR alone. An ACL reconstruction alone did not restore stability with the pivot-shift as well as an ACL reconstruction and an extra-articular procedure. Nonetheless, to avoid potential overconstraint, it is best not to perform an extra-articular procedure at the time of ACL reconstruction if there is no evidence of ALL injury. Conclusion: This systematic review presents the update from the last 5-year literature of LEAP for ACLR with sufficient quality of evidence. The different results in terms of functional outcome might be influenced by, among many others, the duration between injury to surgery. More chronic ACL injuries might benefit more from LEAP. The quality of evidence in studies presented herein can still be improved in terms of methodology, number of samples, and duration of follow-up period. This study is expected to provide a platform for future studies in this field.