Editorial Commentary: Increased Risk of Second Ruptures and Poorer Outcomes After Anterior Cruciate Ligament Injury and Reconstruction in Hypermobile Athletes: A Potential Synergism of Passive Ligamentous and Active Muscular Control of Dynamic Knee Stability Related to Age and Sex?

Graft failure rates were higher and inferior subjective outcomes were observed after anterior cruciate ligament reconstruction in patients with generalized hypermobility. This is a clear and corroborative finding that is highly consilient with other reports of similar studies from the published literature. However, controversy remains regarding other potentially predictive and confounding variables. For example, age, activity level, sex, and dynamic neuromuscular control were not considered in this interesting, important, and potentially impactful study. Dynamic stability of the knee joint is determined by both passive (ligamentous and tendinous) and dynamic (neuromuscular) restraints. Most anterior cruciate ligament (ACL) injuries in high-risk sports such as basketball, football, lacrosse, soccer, and volleyball occur by noncontact mechanisms (landing, deceleration, or lateral pivoting). Noncontact ACL injuries often occur in female athletes by a common 3-part mechanism: dynamic lower extremity valgus loading combined with an extended knee on a single leg. Increased passive laxity of the knee combined with an increased dynamic joint loading profile may lead to the increased ACL injury rates in females. Therefore, the combination of insufficiently taut ligaments and tendons of the lower extremity that may passively destabilize the joint and high knee joint forces and torques that dynamically load an already loose joint may be diagnostic for both primary and secondary ACL injury risk.