Jordy van Sambeeck

Chapter 9 154 dynamic field of research with a lot of opportunities to further optimize treatment for these patients. Some future opportunities for optimalization of treatment of patients with patellofemoral instability will be proposed in the next paragraphs and we will propose a workup of patients with patellofemoral instability based on the answers on the research questions, the discussion and future perspectives of this thesis. Future perspectives on imaging Future opportunities for protocolized imaging and measurements in patients with patellofemoral instability might be found in four-dimensional (4D) scanning. In addition to 3D reconstructed CT- or MR-scanning, 4D means that a controlled movement in one plane is performed and registered during the scan. Using software, a 3D reconstruction of the leg and the movement can be reconstructed and display the important anatomic structures during the performed arc of motion. Rather than scanning during non-weightbearing knee motion, scanning during active range of motion against resistance might be performed. That could demonstrate the tracking of the patella while both static and dynamic stabilizers are active. This could give new data on how the known anatomic risk factors change during range of motion with active dynamic stabilization. It would also provide normal values for these risk factors on 3D and 4D CT-scanning which might be a better representation of relevant abnormal anatomy than the normal values that are currently based on two-dimensional imaging. Another opportunity for 4D CT-scanning is to model the 3D anatomy and movement of a patient and then alter the anatomy using computer software. This will be further worked out in the next section on indications for osteotomies. Future perspectives on indications for osteotomies for patellofemoral instability Improving the workup and consequently the indications for osteotomies for patellofemoral instability, by being able to simulate the surgical correction might be the key to improvement of (patient reported) outcome. Simulating patellar tracking with correction for relevant anatomic risk factors for a specific patient in one model that includes dynamic factors, creates the possibility for modification of these risk factors to an optimum. In contrast to the current practice of determining amount of correction on different static imaging methods. To accomplish a better workup, a digital decision tool for orthopaedic surgeons specialized in treating patients with patellofemoral instability can be developed in the future. For the best outcome, the orthopaedic surgeon needs to collect the right ingredients during the workup. These include both demographic factors and