An investigation of innovative 3D modelling procedures for patient-specific total knee arthroplasty

Total Knee Arthroplasty (TKA) is a widely performed surgical procedure, which is advised to treat knee osteoarthritis. However, the literature reported that 25% of the patients are unsatisfied by the functional outcomes after the intervention. The main causes seem to be the prosthesis malalignment and the anatomical mismatch between the prosthetic components and the different people anatomy. Even if there exist several commercial solutions, whose aim has always been to provide a reliable prosthesis with high survivorship, the most recent scientific literature is focusing its aim to improving the patients’ clinical outcome, kinematics and satisfaction. For this reason, three approaches have been experimented and then discussed with an orthopedic surgeon. Open-source software applications for 3D modelling have been exploited, such as 3D Slicer and Meshmixer. Starting from medical images, through the segmentation process, the 3D model of the knee has been reconstructed. For the first approach, standard off-the-shelf prosthesis have been used for the virtual planning of the intervention. To overcome the limits of this method, two more customized approaches have been experimented. The first one is based on the patient-specific resurfacing prosthesis that fits the patient’s anatomy, preserving the femur and maintaining the natural joint line. The third approach allows to create a customized prosthesis, that is a compromise between the two previous methods. Among the three previous procedures, the most suitable one can be chosen according to the patient’s anatomy, knee size and articular cartilage damage.