A mixed reality application for total hip arthroplasty

Total hip arthroplasty (or total hip replacement) is the current surgical solution for the treatment of advanced coxarthrosis, with the objective of providing mobility and pain relief to patients. For this purpose, surgery can be planned using preoperative images acquired from the patient and navigation systems can also be used during the intervention. Robots have also been used to assist in interventions. In this work, we propose a new mixed reality application for total hip arthroplasty. The surgeon only has to wear HoloLens 2. The application does not require acquiring preoperative or intraoperative images of the patient and uses hand interaction. Interaction is natural and intuitive. The application helps the surgeon place a virtual acetabular cup onto the patient's acetabulum as well as define its diameter. Similarly, a guide for drilling and implant placement is defined, establishing the abduction and anteversion angles. The surgeon has a direct view of the operating field at all times. For validation, the values of the abduction and anteversion angles offered by the application in 20 acetabular cup placements have been compared with real values (ground-truth). From the results, the mean (standard deviation) is 0.375 (0.483) degrees for the error in the anteversion angle and 0.1 (0.308) degrees for the abduction angle, with maximum discrepancies of 1 degree. A study was also carried out on a cadaver, in which a surgeon verified that the application is suitable to be transferred to routine clinical practice, helping in the guidance process for the implantation of a total hip prosthesis.