Augmented Reality-based support for Total Hip Arthroplasty Assessment: an HoloLens 2 Application

??The evaluation of hip implantation success remains one of the most relevant problems in the orthopedic field. There are several factors that can cause its failure, e.g.: aseptic loosening and dislocations of the prosthetic joint due to implant impingement. It is fundamental that the orthopaedist can evaluate, following a total hip arthroplasty, which may be the possible risk factors that would lead to dislocation, or in the worst cases, to implant failure. This thesis focuses on the use of augmented reality for orthopedic surgery support, specifically for the assessment of arthroscopic procedures involving the pelvis and femur area. To this end, an application intended to support the activity of the orthopaedist in the post-operative phase has been developed. This application can highlight, with a high degree of precision, the criticalities related to the femoral head and the acetabulum following the prosthesis implantation, leveraging on a previously developed and already patented simulator. Thanks to its capabilities, it is possible to verify, for some characteristic movements of the hip joint, which are the contact points between the pelvis and femur bones, potential causes of impingement. ??The application has been entirely developed in Unity 3D and deployed on HoloLens 2. The use of this head mounted display for the representation of hip kinematics and implant position can provide the orthopedic surgeon with a deeper understanding of the orientation and position of implanted components, as well as the consequences of such placements, while looking directly at the patient. ??While the simulator itself has already been evaluated in terms of performance and medical validity, the AR-based application that uses it is currently at an advanced state of testing, ready to be evaluated from a medical perspective. Qualitative tests have been performed to evaluate the application and the usability of HoloLens 2 for the intended purpose, considering the interaction with the virtual content and the visual perception of it.