Bioaugmentation in the surgical treatment of anterior cruciate ligament injuries: A review of current concepts and emerging techniques

Abstract

Injuries involving the anterior cruciate ligament are among the most common athletic injuries, and are the most common involving the knee. The anterior cruciate ligament is a key translational and rotational stabilizer of the knee joint during pivoting and cutting activities. Traditionally, surgical intervention in the form of anterior cruciate ligament reconstruction has been recommended for those who sustain an anterior cruciate ligament rupture and wish to remain active and return to sport. The intra-articular environment of the anterior cruciate ligament makes achieving successful healing following repair challenging. Historically, results following repair were poor, and anterior cruciate ligament reconstruction emerged as the gold-standard for treatment. While earlier literature reported high rates of return to play, the results of more recent studies with longer follow-up have suggested that anterior cruciate ligament reconstruction may not be as successful as once thought: fewer athletes are able to return to sport at their preinjury level, and many still go on to develop osteoarthritis of the knee at a relatively younger age. The four principles of tissue engineering (cells, growth factors, scaffolds, and mechanical stimuli) combined in various methods of bioaugmentation have been increasingly explored in an effort to improve outcomes following surgical treatment of anterior cruciate ligament injuries. Newer technologies have also led to the re-emergence of anterior cruciate ligament repair as an option for select patients. The different biological challenges associated with anterior cruciate ligament repair and reconstruction each present unique opportunities for targeted bioaugmentation strategies that may eventually lead to better outcomes with better return-to-play rates and fewer revisions.

Graft healing after anterior cruciate ligament reconstruction (ACLR)

“…Biological modulations like mesenchymal stem cells, growth factors, biomaterials, or biophysical intervention have been applied to improve the healing outcome and these biological strategies have long been reviewed. 71 , 72 From different reviews, we can conclude that majority targeted graft incorporation inside bone tunnels or tendon-bone interface healing. However, it was reported that the graft ruptured most frequently at the femoral insertion 73 and was followed by intra-articular mid-substance.…”

A Novel Approach to Augmenting Allograft Hamstring Anterior Cruciate Ligament Reconstructions Utilizing a Resorbable Type I Collagen Matrix with Platelet Rich Plasma

“…Delay in biologic graft incorporation has been of primary concern when considering allograft failures [19][20][21]. Rappé et al found a 33% failure rate when using irradiated Achilles tendon allografts to a 2.4% failure rate when using nonirradiated Achilles tendon allografts [18].…”

“…The concept of utilizing biologics as an augment for ACLR has gained popularity in recent years [19][20][21][22][23]. Fleissner et al reported on 143 patients who underwent ACLR with autograft augmented with type I collagen matrix hydrated with PRP.…”

“…Consideration of the delicate balance between the attraction of allograft and the respect for biologic graft incorporation is a challenging dilemma for orthopedic surgeons. The introduction of ACLR scaffolds and biologic agents has been discussed to improve healing [20]. A systematic review by Andriolo et al found a positive impact of platelet-rich plasma (PRP) in ACL graft ligamentization and inflammatory modulation.…”

VEGF functionalization of suture tape results in decreased graft inflammatory and catabolic response in a rabbit model of ACL reconstruction

“…While the addition of exogenous compounds can be readily achieved at the time of ACLR, concerns exist regarding appropriate dosing as well as duration of effect given one-time intra-operative administration. 22 An alternative is to employ peptide sequences which reversibly bind and locally concentrate circulating endogenous growth factors. 9 By using such a method, the resultant biologic effect can be sustained and additionally, cellular feedback mechanisms may also better participate in physiologic modulation of growth factor production and, therefore, concentration and availability.…”