Editorial Commentary: Risk Factors of Cyclops Syndrome in Quadriceps Autograft Anterior Cruciate Ligament Reconstruction: More Helpful Data in Weighing Graft Choice.

Arthrofibrosis after anterior cruciate ligament (ACL) reconstruction can be a devastating complication with risk factors and causes not well established. Cyclops syndrome is a subtype involving localized scar anterior to the graft, which is typically treated with arthroscopic debridement. ACL quadriceps autograft is a newly popular graft option for which clinical data continue to develop. However, recent research shows possible increased risk of arthrofibrosis with quadriceps autograft. Possible causes include inability to achieve active terminal knee extension after extensor mechanism graft harvesting; patient characteristics, including female sex, and social, psychological, musculoskeletal, and hormonal differences; larger graft diameter; concomitant meniscus repair; exposed collagen fibers of the graft abrading the fat pad or tibial tunnel or intercondylar notch; smaller notch size; intra-articular cytokine; and biomechanical stiffness of the graft.