Biological Versus Synthetic Grafts in ACL Reconstruction: A Comparative Analysis of Failure Rates, Knee Stability, and Functional Outcomes

Background: Anterior cruciate ligament (ACL) injuries are among the most common and impactful musculoskeletal injuries, particularly in athletic populations. A variety of biological and synthetic grafts are used in surgical reconstruction, each offering different biomechanical properties and long-term outcomes. Materials and Methods: by using terms such as 'ACL reconstruction', 'BPTB', 'hamstring tendon', 'quadriceps tendon', 'LARS', 'Leeds-Keio', and 'GORE-TEX'. Key outcomes included graft failure rates, postoperative knee stability (e.g., KT-1000, Lachman test), and functional outcomes (Lysholm, Tegner, IKDC). Numerical data were pooled descriptively; no formal meta-analysis was performed. Results: Biological grafts, particularly BPTB and quadriceps tendon autografts, demonstrated the lowest failure rates (as low as 1.2%) and superior mechanical stability (>95% achieving Grade 0-1 laxity) compared to synthetic options. Hamstring tendon autografts were slightly less durable but still reliable. Synthetic grafts, and especially GORE-TEX and Leeds-Keio, were associated with higher failure rates (up to 33%) and complications related to poor biological integration. Conclusions: BPTB and QT autografts remain the most reliable options for ACL reconstruction, offering excellent long-term outcomes. While synthetic grafts may be appropriate in select patients, they carry a higher risk of failure and complications. Graft selection should be individualized based on the patient activity level, anatomical considerations, and tolerance for donor-site morbidity.