Page 22 - ISAKOS 2019 Newsletter Volume 1

CURRENT CONCEPTS
Is There a Role for Primary ACL Repair and Biologics?
ACL Injury and Treatment Considerations
It is well recognized that disruption of the ACL alters knee kinematics and significantly increases the risk for knee osteoarthritis (OA), with 60% to 90% of patients demonstrating evidence of knee OA 10 years after ACL reconstruction. Although current methods to reconstruct the ACL generally are perceived to be successful, recent analyses have indicated that normal structure and function of the knee may not be fully restored in many patients undergoing reconstruction. Furthermore, the literature suggests that ACL reconstruction does not reduce the risk of developing OA, as 42% to 90% of affected knees have radiographic evidence of OA within 7 to 12 years after ACL surgery.
Given the expected natural history of progressive articular cartilage injury in a notable proportion of ACL injuries, it is a high priority for treating orthopaedic surgeons to develop techniques that not only achieve good short- to long-term restoration of knee stability but also minimize or eliminate the long-term risk of OA. Previous clinical studies examining ACL repair procedures have demonstrated an excessively high failure rate, which has shifted the treatment paradigm away from primary repair. Importantly, however, advancements in modern surgical instruments must be considered, given their potential to allow for better fixation of injured ligamentous tissue as well as to provide biologic augmentation to overcome the limited native healing capabilities of the ACL.
Because of the evolving understanding of regenerative medicine, biological approaches to augment surgical repair procedures have been exponentially growing over the past several decades. The use of these biologic therapies (including growth factors, autologous blood products, and progenitor cells) has been a prominent focus of current research into ACL healing after repair and is regarded as a potential alternative to ACL reconstruction in well-selected cases. These adjunctive therapies, combined with modern methods of primary repair of the injured ligament, may be an important advancement in the treatment of certain injury patterns. These therapies may have the potential to better preserve joint kinematics by restoring function of the native ligament while also avoiding the risk of certain complications related to ACL reconstruction, such as donor-site morbidity resulting from autologous tendon harvest and postoperative muscular weakness.
Numerous factors have been shown to contribute to the suboptimal healing capacity of the ACL, including (1) the presence of synovial fluid within the intra-articular space (which contributes to persistent gapping between injured ligamentous fibers and inhibits blood clot formation), (2) variations in the post-injury inflammatory response and cell metabolism, (3) intrinsic cell deficiencies, (4) insufficient vascular supply and (5) altered load-bearing characteristics.
Abstract
Jorge Chahla, MD, PhD
Cedars Sinai Kerlan Jobe Institute Santa Monica, CA UNITED STATES
John G. Lane, MD
Musculoskeletal and Joint Research Foundation
San Diego, CA UNITED STATES
Graeme P. Whyte, MD, MSc
Cornell University, Weill Medical College; New York Presbyterian Hospital/Queens New York, NY UNITED STATES
O.A.S.I. Bioresearch Foundation NPO Milan, ITALY
Alberto Gobbi, MD
O.A.S.I. Bioresearch Foundation NPO Milan, ITALY
Anterior cruciate ligament (ACL) injury is one of the most common injuries in orthopaedics; however, limited advancements have been made in recent decades regarding the treatment of this condition. One of the most concerning complications of such an injury is posttraumatic osteoarthritis resulting from progressive cartilage injury. This type of progressive cartilage damage is likely impacted by altered biomechanics, leading to subsequent intra-articular structural damage and changes to the intra-articular milieu. Improved understanding of the pathophysiology of ligamentous healing and several recent studies have shed further light on ACL repair procedures, which previously have been dismissed as a primary treatment option because of the high rate of failure. Our study of a small sample of carefully selected patients demonstrated that ACL primary repair in combination with biological augmentation can offer satisfactory clinical outcomes.
Keywords: anterior cruciate ligament, ACL repair, biomechanics, ACL reconstruction
20 ISAKOS NEWSLETTER 2019: VOLUME I