Figure 4. Repair techniques of the anterior cruciate ligament (ACL): A: repair without augmentation: reinsertion of each bundle using implants without knotting. Microfractures are incorporated in the implantation bed to improve biological repair; B: repair with static augmentation: the ruptured ACL is sutured and the ligament is moreover bridged with a 2.5 mm polyethylene band through the anatomic insertions of the ACL; C: repair with dynamic augmentation: a spring-type device is placed at the tibial insertion to maintain tension of the system throughout knee joint balance; D: repair with biological augmentation: a blood-filled extracellular matrix of bovine origin is interspaced (arrow) between the proximal extremity of the ACL and the bone.