Page 135 - Demo

Patient Specific Instrumentation in ACL reconstruction1337IntroductionIn young active patients who have suffered a rupture of the anterior cruciate ligament (ACL), ACL reconstruction is used to treat symptomatic knee instability.17 Anatomical ACL reconstruction aims for a graft to be implanted on the native footprints of the ACL on the femur and tibia. Nonanatomical placement of the graft in ACL may eliminate anterior/posterior laxity, but normal kinematics will not be fully restored.3,14,23 Also, nonanatomic placement of the ACL graft is associated with an increased risk of graft failure.11 This graft failure, rupture, or elongation, occurs in up to 14% of primary ACL reconstructions11 and does not depend on the type of graft used.9 To reduce graft failure, it is important to address additional posterolateral, posteromedial and collateral laxity,26 but in up to 24% of patients that undergo ACL revision surgery, surgical inaccuracy is the sole reason for failure.7 And in up to 54% of patients, this was an additive cause for failure.7 Malposition of the femoral tunnel was recognized as the most common technical failure (80%).7 Possible contributing factors are procedure- and patient dependent: During the procedure, limited visibility of the femoral footprint during arthroscopy is a known problem1,25and studies show that there is a large individual variation in location and diameter of the femoral footprint of the native ACL.28 Although femoral and tibial bone tunnels are drilled through surgical guide instruments to optimize positioning, current surgical techniques still depend on the intraoperative identification of landmarks and measurements to determine the femoral footprint of the ACL. The use of anatomical landmarks for ensuring anatomic positioning of the graft however remains associated with a high risk of femoral tunnel malposition, which is related to early to midterm failure of the graft.7,11 This emphasizes that current surgical techniques using universal aiming devices seem to fall short in creating a constant and reliable result for a femoral tunnel position at the optimal, individual anatomic footprint of the ACL. To provide consistent results, determining the location of the ACL footprint should not be dependent of surgeon’s experience or intra-operative visual control, and individual variation should be taken into account. Mark Zee.indd 133 03-01-2024 08:56