Page 143 - Demo

Patient Specific Instrumentation in ACL reconstruction1417The accuracy of the segmentation process could be a large contributory factor to the inaccuracy of the current construct. In this study, we have segmented the MRI images semi-automatically. Even though we have observed that repeated segmentation of the same images leads to a minimal change in the total absolute difference in the model, minor impurities of the model may cause the final aiming device to fit incorrect. Nevertheless, we noticed that the fit was very good. A recent review has demonstrated the potential of automated segmentation based on deep learning.5 As this technique develops over time, segmentation may be more accurate and less time consuming.In addition, the construct using polyamide 12 could attribute to lower accuracy of the aiming device, since polyamide 12 contains a certain degree of flexibility. This can lead to a bending of the system. This can be solved by using more rigid materials. Titanium is available for 3D printing, but this is a costly affair. More obvious is the use of 316L stainless steel as it is used for many surgical instruments. 316L stainless steel can be machined by a robotic milling cutter to create the patient specific part for the targeting device.The use of polyamide-12 however, is a cheap option. We have not performed a cost-effectiveness analysis in this study. In this study the total cost for a 3D virtual surgical plan and 3D printed guides were approximately 700-1000 euro per case, with approximately 100-300 euro for the 3D printed guides. We have to conclude that so far, the total deviation has been too large, and we need further improvements to ensure that partially anatomic placement of the ACL graft will not occur. Up to now only one other study has been published regarding the potential of a 3D printed patient specific targeting device for the creation of the femoral tunnel. Rankin et al have reported on a patient specific template that can be used to mark the insertion of the ACL in the notch with a chondropick.22 Rankin et al did not describe the accuracy of their system. Mark Zee.indd 141 03-01-2024 08:56