ACL tunnel placement using 3D printed surgical guides - a porcine feasibility study.

Background: Anterior cruciate ligament reconstruction (ACLR) failures are associated with misplacement of the bone tunnels in up to 88%. The aim of this study is to evaluate the feasibility and accuracy of ACL tunnel placement performed with 3D printed guides.

Methods: 3D models of the femur and tibia from ten porcine specimens were reconstructed using CT scans. ACL tunnel aiming guides were created and fitted to the proximal tibial and distal femoral metaphyseal cortices. Each guide comprised two sleeves to secure the guide to the bone using Kirschner wires and one sleeve for inserting the ACL tunnel guide wire. Guides were printed using a biomedically certified resin on the in-house 3D printer. They were fixed to the antero-medial tibia/distal-lateral femur with Kirschner wires and the ACL guide wire was inserted, then the guides were removed and the ACL guide wire was drilled over. Post-operative CT scans were obtained in order to compare the actual positions of the tunnel to the planned positions. Results are presented as medians and ranges since normal distribution could not be confirmed.

Result: Median deviations between preoperative plan and actual postoperative positon were 1.15 mm (0.7-3 mm) and 0.75 mm (0.3-2.8 mm) for femoral and tibial tunnels, respectively.

Conclusion: Good accuracy of ACL tunnel placement can be achieved using 3D printed guides. Applied to a clinical setting, this technique has the potential to significantly reduce complications due to misplacement of bone tunnels.