Orthobiologics in anterior cruciate ligament injuries.

Anterior cruciate ligament (ACL) injury remains a major challenge in sports medicine because it affects a young and active population and is associated with instability, secondary meniscal and chondral damage, delayed return to sport and post-traumatic osteoarthritis. This narrative review provides an ACL-specific overview of orthobiologics, with an emphasis on the biologic rationale, current clinical applications and the strength of the available evidence. The biologic limitations of the native ACL, particularly its poor intrinsic healing capacity in the intra-articular environment, have spurred interest in strategies to improve graft ligamentization, tendon-bone healing, modulation of inflammation and preservation of native ligament tissue. Platelet-rich plasma is the most widely investigated orthobiologic in ACL surgery; however, clinical findings remain inconsistent, largely because of substantial heterogeneity in preparation methods, leukocyte content, activation protocols and delivery sites. Bone marrow aspirate concentrate may provide a broader cellular and cytokine profile, but current studies suggest that any benefit is limited mainly to selective early imaging or functional recovery parameters, without consistent improvement in longer-term patient-reported outcomes. Other cell-based approaches, including adipose- and synovium-derived therapies, remain investigational and lack sufficient evidence to support routine clinical use. In contrast, scaffold-based biologic repair, particularly bridge-enhanced ACL repair, currently represents the most convincing example of successful biologic translation in this field, with prospective clinical studies demonstrating non-inferior outcomes compared with autograft reconstruction in appropriately selected patients. The available literature remains difficult to interpret because of inconsistent product characterization, variable indications, heterogeneous surgical techniques, frequent reliance on surrogate imaging outcomes and underpowered clinical trials. Orthobiologics in ACL surgery should therefore be considered selective adjuncts rather than standard treatment. Future progress will depend on indication-specific trial design, improved reporting of biologic composition and delivery methods and prioritization of clinically relevant outcomes such as graft failure, knee stability, return to sport and long-term joint preservation. Level of Evidence: Level V, narrative review.