Anterior cruciate ligament reconstruction: a look at prosthetics - past, present and possible future

ABSTRACT: Biological tissue autograft reconstruction using the patellar tendon or quadrupled semitendinosus/gracilis tendons has become the most popular procedure in surgical treatment of a ruptured ACL. This article provides a review of the history of the use of prosthetics with respect to ACL reconstruction grafts including Carbon Fibre, Gore-Tex and Dacron prosthetics as well as the Leeds-Keio Artificial Ligament and the Kennedy Ligament Augmentation Device (LAD). Emphasis is placed on the Ligament Advanced Reinforcement System (LARS) as preliminary investigations of its use have been encouraging. Significant progress has been made recently with respect to the understanding of ACL anatomy, composition, biomechanics, and healing processes, leading to innovative techniques using approaches based in tissue engineering principles and computer – assisted surgery. While research into improved ACL treatment options continues, the synthesis of recent advancements provides a new optimism towards the regeneration of an ACL mirroring its original stability, function, and longevity.

Journey around the Notch: A Systematic Review on the History of ACL Reconstruction in the United States

The evolution of anterior cruciate ligament (ACL) surgery, seemingly circular at times, informs and provides context for past and current controversies in ACL management. The purpose of this systematic review is to objectively summarize the historical course of ACL reconstruction and repair in the United States over the last 40 years. Femoral tunnel drilling and graft selection have evolved dramatically over the last few decades. An initial focus on restoring ACL anatomy was for a period sacrificed for decreased operative morbidity. However, recent developments in operative techniques aim to restore ACL anatomy while also achieving minimal operative morbidity. Despite this historically iterative process, there remains no perfect choice for the treatment of ACL tears. Continued research on ACL repair, anatomic graft placement, graft choice, and augmentation will help our patients over the next generation.

Primary Anterior Cruciate Ligament Reconstruction. How Do We Do It?

Anterior cruciate ligament (ACL) tears are frequently seen in current practice mostly affecting the young, active subjects, and usually require ligament reconstruction in order to restore normal knee kinematics. As worldwide interest in anatomic reconstruction grew over the last decade, we have also refined our technique in order to restore the anatomical function as near to the normal as possible. This anatomical restoration concept is believed to prevent the onset of osteoarthritis, which the non-anatomic reconstructions fail to attain. The knowledge gained from the ACL anatomy, function and kinematics has helped in developing the current anatomic methods of reconstruction, which take into account patient anatomy, the rupture pattern, as well as the comorbidities. We present our approach to anatomical single- and double-bundle ACL reconstruction.

Three-Dimensional Anatomic Evaluation of the Anterior Cruciate Ligament for Planning Reconstruction

Anatomic study related to the anterior cruciate ligament (ACL) reconstruction surgery has been developed in accordance with the progress of imaging technology. Advances in imaging techniques, especially the move from two-dimensional (2D) to three-dimensional (3D) image analysis, substantially contribute to anatomic understanding and its application to advanced ACL reconstruction surgery. This paper introduces previous research about image analysis of the ACL anatomy and its application to ACL reconstruction surgery. Crucial bony landmarks for the accurate placement of the ACL graft can be identified by 3D imaging technique. Additionally, 3D-CT analysis of the ACL insertion site anatomy provides better and more consistent evaluation than conventional “clock-face” reference and roentgenologic quadrant method. Since the human anatomy has a complex three-dimensional structure, further anatomic research using three-dimensional imaging analysis and its clinical application by navigation system or other technologies is warranted for the improvement of the ACL reconstruction.

Tissue-Engineering Strategies for Ligament Reconstruction

The majority of musculoskeletal injuries involve the soft connective tissues including cartilage, meniscus, tendon, and ligament. In contrast to bone tissue, which regenerates after injury, these soft tissues tend to heal poorly through formation of weak, disorganized scar tissue. In fact certain soft-tissue injuries cannot heal on their own so surgical repair or complete reconstruction is required to restore function. Biological grafts (autografts and allografts) and “permanent” synthetic prostheses are currently used to reconstruct large soft-tissue defects. Autografts (a patient's own tissue transferred to another site) can be successful, but as you “rob Peter to pay Paul,” complications at the donor site can be significant. Allografts (transplants from another human) are in short supply and carry the risk of rejection or disease transmission. In general, permanent synthetic prostheses fail to withstand long-term mechanical loading associated with the musculoskeletal system. New strategies are clearly needed to manage musculoskeletal soft-tissue reconstruction.Several tissue-engineering strategies are potentially useful to enhance repair of these troublesome injuries or to induce regeneration. One interesting approach (developed for skin and cartilage regeneration) combines scaffolds, cells, and cell signals to grow living tissue analogues in the laboratory. Scaffolds are natural or synthetic biomaterials upon which the cells attach and grow. The cells may be fibroblasts, chondrocytes, etc., depending on the specific application. Influential cell signals can include attachment factors, growth factors, and mechanical loads.Our laboratory is developing a similar approach for ligament reconstruction. Ligaments are the strong, flexible bands of collagenous tissue that connect bone-to-bone to provide a delicate balance of stability and flexibility to the joints of the body. The anterior cruciate ligament (ACL) is the primary stabilizer of the knee and is frequently injured in sporting activities and accidents. Serious ACL injuries can lead to disability and progressive degeneration of cartilage and meniscus that normally serve as shock absorbers in the joint. Anterior-cruciate-ligament ruptures do not heal without surgical intervention, due to a poor intrinsic healing response and poor vascularity. To restore normal joint function, ruptured ACLs can be surgically reconstructed using a patellar-tendon autograft or allograft. While significant progress has been made in understanding ACL anatomy, structure, biomechanics, and healing, there is still no biological graft or biomaterial ideally suited for ACL reconstruction.