Can we afford to ignore the biology of joint healing and graft incorporation after ACL reconstruction?

Abstract

Anterior cruciate ligament (ACL) reconstruction is successful at restoring stability to return ACL injured patients to high‐demand work, sports, and recreational activities. The development of posttraumatic osteoarthritis (OA) in roughly half of patients just 10–15 years after ACLR highlight the need to improve clinical care pathways. Graft failure and reinjury rates, which further increase OA risk, also remain high for younger and more active patients. The biological components of joint recovery and graft incorporation, therefore, impact short‐ and long‐term clinical outcomes. Biochemical and magnetic resonance imaging (MRI) data show substantial compromise of articular cartilage metabolism and matrix composition after ACL injury and reconstructive surgery suggesting a potential need for activity modulation in early recovery. Furthermore, joint recovery is variable with compositional MRI studies showing progressive cartilage degeneration 1 and 2 years after ACLR. Biopsy and MRI studies also show high variability in ACL graft characteristics within the 1st year after ACLR followed by continued graft maturation into the 2nd year and beyond. To improve the care of ACL injured patients, there is a critical need for clinical attention and scientific inquiry into timing the reintroduction of higher load activities in relationship to neuromuscular recovery, joint biology, and graft maturation. In addition to symptomatic and mechanical recovery, development and validation of biological markers for joint and cartilage homeostasis as well as ACL graft healing are needed for personalized decision making on rehabilitation needs, reduction of OA risk, and resumption of athletic, recreational, and vocational activities.

Anterior Cruciate Ligament Reconstruction Surgery: Creating a Permissive Healing Phenotype in Military Personnel and Civilians for Faster Recovery

“…A form of osteoarthritis from an accelerated form of inflammation, cartilage degeneration and joint dysfunction that causes stiffness and pain. 3,4,[31][32][33][34]…”

“…Longer-term clinical complications are equally debilitating. Regardless of successful ACL stabilization, 4%-35% of patients will develop progressive arthrofibrosis [29][30][31] and roughly 50% of patients will develop PTOA within 15 years 3,4,[32][33][34] (Table I). Compositional magnetic resonance imaging (MRI) studies suggest that progressive cartilage degeneration begins 1-2 years after the initial injury 4 and radiographic PTOA indications 10 years after the initial injury.…”

“…Despite successful repair and rehabilitation, most people will experience increasing impairment of the joint. [2][3][4] The primary function of the ACL is to prevent the tibia from sliding anteriorly past the femur (extended knee) and to stabilize the knee from excessive rotational, pivot-shift movements (Fig. 1).…”

“…Injuries range from mild, such as a small tear, to severe, such as when the ligament tears completely or when the ligament and part of the bone separate from the rest of the bone. 3,4,13,20…”

ACL special issue, editors

“…Dr. Chu shines a light on what she calls the "silent" process of ACL graft healing, using cutting edge imaging methods to detail the 2-year long maturation process from an avascular, aneural tendon graft to mature incorporated structure that functions as an ACL. 6 Dr. Elisaveta Kon presents a systematic review of whether biologics, a particularly contentious set of interventions, can help facilitate healing after ACL injury and reconstruction. The review underscores that evidence is still lacking to support the use of biologic agents and that no clinical superiority has been demonstrated when using platelet-rich plasma (PRP) in ACL reconstruction.…”