Computer patient-specific 3D modeling and custom-made guides for revision ACL surgery

Introduction: Revision Anterior cruciate ligament reconstruction (ACLR) is a challenging surgery occurring in 3-24% of primary reconstructions. A meticulous planning to study the precise size and location of both femoral and tibial bone tunnels is mandatory. The aim of the study was to evaluate the intra- and inter-operator differences in the decision-making process between experienced surgeons after they were asked to make pre-operative planning for ACL revision reconstruction with the use of both the CT scan and a 3D printed model of the knee. Materials and methods: Data collected from 23 consecutive patients undergoing revision of ACLR for graft failure at a single Institute between September 2018 and February 2020 were prospectively reviewed. The double-blinded collected data were presented to three board-certificate attending surgeons. Surgeons were asked to decide whether to perform one-stage or two-stage revision ACLR based on the evaluation of the CT scan images and the 3D printed custom-made models at two different rounds, T0 and T1 respectively, seven days apart one from the other. Results: Inter-operator consensus following technical mistake was 52% at T0 and 56% at T1 using the CT scans, meanwhile concordance was 95% at T0 and 94% at T1 using the 3D models. Concordance between surgeons following new knee injury was 66% at T0 and 70% at T1 using CT scans, while concordance was 96% both at T0 and T1 using 3D models. Intra-operative variability using 3D models was extremely low: concordance at T0 and T1 was 98%. McNamar test showed a statistical significance in the use of 3D model for preoperative planning (p < 0.005). 3D printed model reliability resulted to be higher compared to CT as intra-operator surgery technique selection was not modified throughout time from T0 to T1 (p < 0.005). Conclusion: The use of 3D printed models had the most impact when evaluating femoral and tibial tunnels, resulting to be a useful instrument during pre-operative planning of revision ACLR between attending surgeons with medium-high workflow.

Publication History

Received: 13 July 2023

Accepted after revision: 23 April 2024

Accepted Manuscript online:
27 April 2024