A novel approach of intra-operative shape acquisition of the tibio-femoral joints using 3D laser scanning for computer assisted orthopaedic surgery

Background: Image registration (IR) is an important process of developing a spatial relationship between pre - operative data and physical patient in the operation theatre. Current IR techniques for Computer Assisted Orthopaedic Surgery (CAOS) are time consuming and costly. There is a need to automate and accelerate this process. Methods: Bespoke quick, cost effective, contactless and automated 3D laser scanning techniques based on the DAVID Laserscanner method were designed. 10 cadaveric knee joints were intra - operatively laser scanned and were registered with the pre - operative MRI scans. The results are supported with a concurrent validity study. Results: The average absolute errors between scan models were systematically less than 1mm. Errors on femoral surfaces were higher than tibial surfaces. Additionally, scans acquired through the large exposure produced higher errors than the smaller exposure. Conclusion: This study has provided proof of concept for a novel automated shape acquisition and registration technique for CAOS.