Images were visualized and reconstructed using Amira visualization software (Amira®, Visage Imaging, San Diego, CA). Where necessary, we segmented bone structures on CT slices manually. To view and reconstruct DICOM data, the open-source DICOM reader OsiriX was used. Also, Co-registration of CT and OCT images was performed using custom-made software. DICOM data of a matching CT- and OCT scan were utilized for fusion between the two modalities. Data was resampled for display in identical voxel sizes, enabling a true scale overlay of the images. Images were co-registered manually in three planes, using landmarks that can be identified on both modalities, such as the OCT probe and its position, the shape of the intra-articular space, air bubbles and regions of soft tissue. Co-registered images were visualized with false color overlay of the OCT data and segmented bone structures on CT.