Introduction: The agenesis of the anterior cruciate ligament (ACL) is a rare condition infrequently diagnosed as an isolated malformation. Still, it is linked to systemic disorders such as Ehlers-Danlos syndrome (EDS), an inheritable connective tissue disorder characterized by joint hyperlaxity and increased risk of dislocations and subluxations. The literature on ACL reconstruction in EDS patients is minimal, and ours is the second case report describing the surgical management of an ACL agenesis in a patient with this pathology. Case Presentation:The present case report describes the surgical management of an 11-year-old patient affected by EDS. The particularity of this case is that the young patient presented with complete agenesis of the ACL in the right knee resulting in severe joint instability needing surgical reconstruction. This case represented a challenge for the orthopedic surgeon due to the need to improve joint stability without compromising the bone growth of a young patient with open physes while also dealing with tissues that have reduced mechanical properties due to the patient’s disease. The patient was therefore treated with an Achilles tendon allograft through a modified version of the typical ACL reconstructive surgery that excluded the classical tunnel drilling in the tibia and femur. Conclusion:At a 2-year follow-up, this technique proved to be an effective treatment for ACL agenesis in an EDS patient. It could provide a reference for surgeons facing similar cases. The proposed surgical technique, completely extra-epiphyseal, could also be applied to healthy young patients with open physes to avoid future growth disturbances. Keywords:Anterior cruciate ligament, anterior cruciate ligament agenesis, Ehlers-Danlos, pediatric anterior cruciate ligament reconstruction, anterior cruciate ligament reconstruction, anterior cruciate ligament agenesis.